ov-java.cc

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/*

Copyright (C) 2007, 2013 Michael Goffioul

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "defun.h"
#include "error.h"
#include "fpucw.h"

#if HAVE_FPU_CONTROL_H
#include <fpu_control.h>
#endif

#if defined HAVE_JAVA

#if defined (HAVE_WINDOWS_H)
#include <windows.h>
#endif

#include <algorithm>
#include <map>
#include <iostream>
#include <fstream>

#include <clocale>

#include "Cell.h"
#include "cmd-edit.h"
#include "defaults.h"
#include "file-ops.h"
#include "file-stat.h"
#include "load-path.h"
#include "oct-env.h"
#include "oct-shlib.h"
#include "ov-java.h"
#include "parse.h"
#include "variables.h"

typedef jint (JNICALL *JNI_CreateJavaVM_t) (JavaVM **pvm, JNIEnv **penv, void *args);
typedef jint (JNICALL *JNI_GetCreatedJavaVMs_t) (JavaVM **pvm, jsize bufLen, jsize *nVMs);

extern "C"
{
  JNIEXPORT jboolean JNICALL
  Java_org_octave_Octave_call (JNIEnv *, jclass, jstring, jobjectArray,
                               jobjectArray);
  JNIEXPORT void JNICALL
  Java_org_octave_OctaveReference_doFinalize (JNIEnv *, jclass, jint);

  JNIEXPORT void JNICALL
  Java_org_octave_Octave_doInvoke (JNIEnv *, jclass, jint, jobjectArray);

  JNIEXPORT void JNICALL
  Java_org_octave_Octave_doEvalString (JNIEnv *, jclass, jstring);

  JNIEXPORT jboolean JNICALL
  Java_org_octave_Octave_needThreadedInvokation (JNIEnv *, jclass);
}

static JavaVM *jvm = 0;
static bool jvm_attached = false;

// Need to keep hold of the shared library handle until exit.
static octave_shlib jvm_lib;

static std::map<int,octave_value> listener_map;
static std::map<int,octave_value> octave_ref_map;
static int octave_java_refcount = 0;
static long octave_thread_ID = -1;

bool Vjava_matrix_autoconversion = false;
bool Vjava_unsigned_autoconversion = true;
bool Vdebug_java = false;

class JVMArgs
{
public:

  JVMArgs (void)
  {
    vm_args.version = JNI_VERSION_1_2;
    vm_args.nOptions = 0;
    vm_args.options = 0;
    vm_args.ignoreUnrecognized = false;
  }

  ~JVMArgs (void)
  {
    clean ();
  }

  JavaVMInitArgs* to_args ()
  {
    update ();
    return &vm_args;
  }

  void add (const std::string& opt)
  {
    java_opts.push_back (opt);
  }

  void read_java_opts (const std::string& filename)
  {
    std::ifstream js (filename.c_str ());

    if (! js.bad () && ! js.fail ())
      {
        std::string line;

        while (! js.eof () && ! js.fail ())
          {
            std::getline (js, line);
            if (line.length () > 2
                && (line.find ("-D") == 0 || line.find ("-X") == 0))
              java_opts.push_back (line);
            else if (line.length () > 0 && Vdebug_java)
              std::cerr << "invalid JVM option, skipping: " << line << std::endl;
          }
      }
  }

private:

  void clean (void)
  {
    if (vm_args.options != 0)
      {
        for (int i = 0; i < vm_args.nOptions; i++)
          delete [] vm_args.options[i].optionString;
        delete [] vm_args.options;

        vm_args.options = 0;
        vm_args.nOptions = 0;
      }
  }

  void update (void)
  {
    clean ();

    if (java_opts.size () > 0)
      {
        int index = 0;

        vm_args.nOptions = java_opts.size ();
        vm_args.options = new JavaVMOption [vm_args.nOptions];
        for (std::list<std::string>::const_iterator it = java_opts.begin ();
             it != java_opts.end (); ++it)
          {
            if (Vdebug_java)
              std::cout << *it << std::endl;
            vm_args.options[index++].optionString = strsave ((*it).c_str ());
          }
        java_opts.clear ();
      }
  }

private:

  JavaVMInitArgs vm_args;

  std::list<std::string> java_opts;
};

#ifdef __WIN32__
static std::string
read_registry_string (const std::string& key, const std::string& value)
{
  HKEY hkey;
  DWORD len;

  std::string retval;

  if (! RegOpenKeyEx (HKEY_LOCAL_MACHINE, key.c_str (), 0, KEY_READ, &hkey))
    {
      if (! RegQueryValueEx (hkey, value.c_str (), 0, 0, 0, &len))
        {
          retval.resize (len);
          if (RegQueryValueEx (hkey, value.c_str (), 0, 0,
                               (LPBYTE)&retval[0], &len))
            retval = "";
          else if (retval[len-1] == '\0')
            retval.resize (--len);
        }
      RegCloseKey (hkey);
    }

  return retval;
}

static std::string
get_module_filename (HMODULE hMod)
{
  int n = 1024;
  std::string retval (n, '\0');
  bool found = false;

  while (n < 65536)
    {
      int status = GetModuleFileName(hMod, &retval[0], n);

      if (status < n)
        {
          retval.resize (n);
          found = true;
          break;
        }
      else
        {
          n *= 2;
          retval.resize (n);
        }
    }
  return (found ? retval : "");
}

static void
set_dll_directory (const std::string& dir = "")
{
  typedef BOOL (WINAPI *dllfcn_t) (LPCTSTR path);

  static dllfcn_t dllfcn = 0;
  static bool first = true;

  if (! dllfcn && first)
    {
      HINSTANCE hKernel32 = GetModuleHandle ("kernel32");
      dllfcn = reinterpret_cast<dllfcn_t> (GetProcAddress (hKernel32,
                                           "SetDllDirectoryA"));
      first = false;
    }

  if (dllfcn)
    dllfcn (dir.empty () ? 0 : dir.c_str ());
}
#endif

static std::string
initial_java_dir (void)
{
  static std::string java_dir;

  if (java_dir.empty ())
    {
      java_dir = octave_env::getenv ("OCTAVE_JAVA_DIR");

      if (java_dir.empty ())
        java_dir = Vfcn_file_dir + file_ops::dir_sep_str () + "java";
    }

  return java_dir;
}

// Read the content of a file filename (usually "classpath.txt")
//
// Returns a string with all lines concatenated and separated
// by the path separator character.
// The return string also starts with a path separator so that
// it can be appended easily to a base classpath.
//
// The file "classpath.txt" must contain single lines, each
// with a classpath.
// Comment lines starting with a '#' or a '%' in column 1 are allowed.

static std::string
read_classpath_txt (const std::string& filepath)
{
  std::string classpath;

  std::ifstream fs (filepath.c_str ());

  if (! fs.bad () && ! fs.fail ())
    {
      std::string line;

      while (! fs.eof () && ! fs.fail ())
        {
          std::getline (fs, line);

          if (line.length () > 0)
            {
              if (line[0] == '#' || line[0] == '%')
                ; // skip comments
              else
                {
                  // prepend separator character
                  classpath.append (dir_path::path_sep_str ());

                  // append content of line without whitespace
                  int last = line.find_last_not_of (" \t\f\v\r\n");

                  classpath.append (file_ops::tilde_expand (line.substr (0, last+1)));
                }
            }
        }
    }

  return (classpath);
}

static std::string
initial_class_path (void)
{
  std::string java_dir = initial_java_dir ();

  std::string retval = java_dir;

  // find octave.jar file
  if (! retval.empty ())
    {
      std::string sep = file_ops::dir_sep_str ();

      std::string jar_file = java_dir + sep + "octave.jar";

      file_stat jar_exists (jar_file);

      if (jar_exists)
        {
          // initialize static classpath to octave.jar
          retval = jar_file;

          // The base classpath has been set.
          // Try to find an optional file specifying classpaths in 3 places.
          // 1) Current directory
          // 2) User's home directory
          // 3) Octave installation directory where octave.jar resides

          // The filename is "javaclasspath.txt", but historically
          // has been "classpath.txt" so both are supported.
          std::string cp_list[] = {"javaclasspath.txt", "classpath.txt"};

          for (int i=0; i<2; i++)
            {
              std::string filename = cp_list[i];
              std::string cp_file = filename;
              file_stat   cp_exists;

              // Try to find classpath file in the current directory.

              cp_exists = file_stat (cp_file);
              if (cp_exists)
                {
                  // File found.  Add its contents to the static classpath.
                  std::string classpath = read_classpath_txt (cp_file);
                  retval.append (classpath);
                }

              // Try to find classpath file in the user's home directory.

              cp_file = "~" + sep + filename;
              cp_file = file_ops::tilde_expand (cp_file);
              cp_exists = file_stat (cp_file);
              if (cp_exists)
                {
                  // File found.  Add its contents to the static classpath.
                  std::string classpath = read_classpath_txt (cp_file);
                  retval.append (classpath);
                }

              // Try to find classpath file in the Octave install directory.

              cp_file = java_dir + sep + filename;
              cp_exists = file_stat (cp_file);
              if (cp_exists)
                {
                  // File found.  Add its contents to the static classpath.
                  std::string classpath = read_classpath_txt (cp_file);
                  retval.append (classpath);
                }
            }
        }
      else
        throw std::string ("octave.jar does not exist: ") + jar_file;
    }
  else
    throw std::string ("initial java dir is empty");

  return retval;
}

#ifndef _FPU_DEFAULT
#if defined __i386__ || defined __x86_64__
#define _FPU_DEFAULT 0x037f
#else
#define _FPU_DEFAULT 0
#endif
#endif

static void
restore_fpu_state (void)
{
  fpucw_t cw = GET_FPUCW ();
  if (cw != _FPU_DEFAULT)
    SET_FPUCW (_FPU_DEFAULT);
}

static void
initialize_jvm (void)
{
  // Most of the time JVM already exists and has been initialized.
  if (jvm)
    return;

  JNIEnv *current_env;
  const char *static_locale = setlocale (LC_ALL, 0);
  const std::string locale (static_locale);

#if defined (__WIN32__)

  HMODULE hMod = GetModuleHandle ("jvm.dll");
  std::string jvm_lib_path;
  std::string old_cwd;

  if (hMod)
    {
      // JVM seems to be already loaded, better to use that DLL instead
      // of looking in the registry, to avoid opening a different JVM.
      jvm_lib_path = get_module_filename (hMod);

      if (jvm_lib_path.empty ())
        throw std::string ("unable to find Java Runtime Environment");
    }
  else
    {
      // In windows, find the location of the JRE from the registry
      // and load the symbol from the dll.
      std::string key, value;

      key = "software\\javasoft\\java runtime environment";

      value = octave_env::getenv ("JAVA_VERSION");
      if (value.empty ())
        {
          value = "Currentversion";
          std::string regval = read_registry_string (key,value);

          if (regval.empty ())
            throw std::string ("unable to find Java Runtime Environment: ") + key + "::" + value;
          value = regval;
        }

      key = key + "\\" + value;
      value = "RuntimeLib";
      jvm_lib_path = read_registry_string (key, value);
      if (jvm_lib_path.empty ())
        throw std::string ("unable to find Java Runtime Environment: ") + key + "::" + value;

      std::string jvm_bin_path;

      value = "JavaHome";
      jvm_bin_path = read_registry_string (key, value);
      if (! jvm_bin_path.empty ())
        {
          jvm_bin_path = (jvm_bin_path + std::string ("\\bin"));

          old_cwd = octave_env::get_current_directory ();

          set_dll_directory (jvm_bin_path);
          octave_env::chdir (jvm_bin_path);
        }
    }

#else  // Not Win32 system

  // JAVA_LDPATH determined by configure and set in config.h
#if defined (__APPLE__)
  std::string jvm_lib_path = JAVA_LDPATH + std::string ("/libjvm.dylib");
#else
  std::string jvm_lib_path = JAVA_LDPATH + std::string ("/libjvm.so");
#endif

#endif

  jsize nVMs = 0;

# if !defined (__APPLE__) && !defined (__MACH__)

  octave_shlib lib (jvm_lib_path);

  if (!lib)
    throw std::string ("unable to load Java Runtime Environment from ") + jvm_lib_path;

#if defined (__WIN32__)

  set_dll_directory ();

  if (! old_cwd.empty ())
    octave_env::chdir (old_cwd);

#endif

  JNI_CreateJavaVM_t create_vm =
    reinterpret_cast<JNI_CreateJavaVM_t> (lib.search ("JNI_CreateJavaVM"));
  JNI_GetCreatedJavaVMs_t get_vm =
    reinterpret_cast<JNI_GetCreatedJavaVMs_t> (lib.search ("JNI_GetCreatedJavaVMs"));

  if (!create_vm)
    throw std::string ("unable to find JNI_CreateJavaVM in ") + jvm_lib_path;

  if (!get_vm)
    throw std::string ("unable to find JNI_GetCreatedJavaVMs in ") + jvm_lib_path;

  if (get_vm (&jvm, 1, &nVMs) == 0 && nVMs > 0)

#else

  // FIXME: There exists a problem on the Mac platform that
  //   octave_shlib lib (jvm_lib_path)
  // doesn't work with 'not-bundled' *.oct files.

  if (JNI_GetCreatedJavaVMs (&jvm, 1, &nVMs) == 0 && nVMs > 0)

#endif

    {
      // At least one JVM exists, try to attach to it

      switch (jvm->GetEnv (reinterpret_cast<void **> (&current_env), JNI_VERSION_1_2))
        {
        case JNI_EDETACHED:
          // Attach the current thread
          JavaVMAttachArgs vm_args;
          vm_args.version = JNI_VERSION_1_2;
          vm_args.name = const_cast<char *> ("octave");
          vm_args.group = 0;
          if (jvm->AttachCurrentThread (reinterpret_cast<void **> (&current_env),
                                        &vm_args) < 0)
            throw std::string ("JVM internal error, unable to attach octave to existing JVM");
          break;

        case JNI_EVERSION:
          throw std::string ("JVM internal error, the required JNI version is not supported");
          break;

        case JNI_OK:
          // Don't do anything, the current thread is already attached to JVM
          break;
        }

      jvm_attached = true;
      //printf ("JVM attached\n");
    }
  else
    {
      // No JVM exists, create one

      JVMArgs vm_args;

      vm_args.add ("-Djava.class.path=" + initial_class_path ());
      vm_args.add ("-Xrs");
      vm_args.add ("-Djava.system.class.loader=org.octave.OctClassLoader");
      vm_args.read_java_opts (initial_java_dir () + file_ops::dir_sep_str () + "java.opts");

# if !defined (__APPLE__) && !defined (__MACH__)

      if (create_vm (&jvm, &current_env, vm_args.to_args ()) != JNI_OK)
        throw std::string ("unable to start Java VM in ")+jvm_lib_path;
      //printf ("JVM created\n");
    }

  jvm_lib = lib;

#else

      if (JNI_CreateJavaVM (&jvm, reinterpret_cast<void **> (&current_env),
                            vm_args.to_args ()) != JNI_OK)
        throw std::string ("unable to start Java VM in ")+jvm_lib_path;

    }

#endif

  setlocale (LC_ALL, locale.c_str ());
}

static void
terminate_jvm (void)
{
  if (jvm)
    {
      if (jvm_attached)
        jvm->DetachCurrentThread ();
      else
        jvm->DestroyJavaVM ();

      jvm = 0;
      jvm_attached = false;

      if (jvm_lib)
        jvm_lib.close ();

      restore_fpu_state ();
    }
}

std::string
jstring_to_string (JNIEnv* jni_env, jstring s)
{
  std::string retval;

  if (jni_env)
    {
      const char *cstr = jni_env->GetStringUTFChars (s, 0);
      retval = cstr;
      jni_env->ReleaseStringUTFChars (s, cstr);
    }

  return retval;
}

std::string
jstring_to_string (JNIEnv* jni_env, jobject obj)
{
  std::string retval;

  if (jni_env && obj)
    {
      jclass_ref cls (jni_env, jni_env->FindClass ("java/lang/String"));
      if (cls)
        {
          if (jni_env->IsInstanceOf (obj, cls))
            retval = jstring_to_string (jni_env,
                                        reinterpret_cast<jstring> (obj));
        }
    }

  return retval;
}

bool
octave_java::is_java_string (void) const
{
  JNIEnv *current_env = thread_jni_env ();

  if (current_env && java_object)
    {
      jclass_ref cls (current_env, current_env->FindClass ("java/lang/String"));
      return current_env->IsInstanceOf (java_object, cls);
    }

  return false;
}

static octave_value
check_exception (JNIEnv* jni_env)
{
  octave_value retval;

  jthrowable_ref ex (jni_env, jni_env->ExceptionOccurred ());

  if (ex)
    {
      if (Vdebug_java)
        jni_env->ExceptionDescribe ();

      jni_env->ExceptionClear ();

      jclass_ref jcls (jni_env, jni_env->GetObjectClass (ex));
      jmethodID mID = jni_env->GetMethodID (jcls, "toString",
                                            "()Ljava/lang/String;");
      jstring_ref js (jni_env,
                      reinterpret_cast<jstring> (jni_env->CallObjectMethod (ex, mID)));
      std::string msg = jstring_to_string (jni_env, js);

      error ("[java] %s", msg.c_str ());
    }
  else
    retval = Matrix ();

  return retval;
}

static jclass
find_octave_class (JNIEnv *jni_env, const char *name)
{
  static std::string class_loader;
  static jclass uiClass = 0;

  jclass jcls = jni_env->FindClass (name);

  if (jcls == 0)
    {
      jni_env->ExceptionClear ();

      if (! uiClass)
        {
          if (class_loader.empty ())
            {
              jclass_ref syscls (jni_env,
                                 jni_env->FindClass ("java/lang/System"));
              jmethodID mID = jni_env->GetStaticMethodID (syscls, "getProperty", "(Ljava/lang/String;)Ljava/lang/String;");
              jstring_ref js (jni_env, jni_env->NewStringUTF ("octave.class.loader"));
              js = reinterpret_cast<jstring> (jni_env->CallStaticObjectMethod (syscls, mID, jstring (js)));
              class_loader = jstring_to_string (jni_env, jstring (js));
              std::replace (class_loader.begin (), class_loader.end (), '.', '/');
            }

          jclass_ref uicls (jni_env, jni_env->FindClass (class_loader.c_str ()));

          if (! uicls)
            {
              jni_env->ExceptionClear ();

              /* Try the netbeans way */
              std::replace (class_loader.begin (), class_loader.end (), '/', '.');
              jclass_ref jcls2 (jni_env, jni_env->FindClass ("org/openide/util/Lookup"));
              jmethodID mID = jni_env->GetStaticMethodID (jcls2, "getDefault", "()Lorg/openide/util/Lookup;");
              jobject_ref lObj (jni_env, jni_env->CallStaticObjectMethod (jcls2, mID));
              mID = jni_env->GetMethodID (jcls2, "lookup", "(Ljava/lang/Class;)Ljava/lang/Object;");
              jclass_ref cLoaderCls (jni_env, jni_env->FindClass ("java/lang/ClassLoader"));
              jobject_ref cLoader (jni_env, jni_env->CallObjectMethod (lObj, mID, jclass (cLoaderCls)));
              mID = jni_env->GetMethodID (cLoaderCls, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;");
              jstring_ref js (jni_env, jni_env->NewStringUTF (class_loader.c_str ()));
              uicls = reinterpret_cast<jclass> (jni_env->CallObjectMethod (cLoader, mID, jstring (js)));
            }

          if (uicls)
            uiClass = reinterpret_cast<jclass> (jni_env->NewGlobalRef (jclass (uicls)));
        }

      if (uiClass)
        {
          jmethodID mID = jni_env->GetStaticMethodID (uiClass, "findClass", "(Ljava/lang/String;)Ljava/lang/Class;");
          jstring_ref js (jni_env, jni_env->NewStringUTF (name));
          jcls = reinterpret_cast<jclass> (jni_env->CallStaticObjectMethod (uiClass, mID, jstring (js)));
        }
    }

  return jcls;
}

static dim_vector
compute_array_dimensions (JNIEnv* jni_env, jobject obj)
{
  jobjectArray_ref jobj (jni_env, reinterpret_cast<jobjectArray> (obj));
  jclass_ref jcls (jni_env, jni_env->GetObjectClass (obj));
  jclass_ref ccls (jni_env, jni_env->GetObjectClass (jcls));
  jmethodID isArray_ID = jni_env->GetMethodID (ccls, "isArray", "()Z");
  jmethodID getComponentType_ID = jni_env->GetMethodID (ccls, "getComponentType", "()Ljava/lang/Class;");

  dim_vector dv (1, 1);
  int idx = 0;

  jobj.detach ();
  while (jcls && jni_env->CallBooleanMethod (jcls, isArray_ID))
    {
      int len = (jobj ? jni_env->GetArrayLength (jobj) : 0);
      if (idx >= dv.length ())
        dv.resize (idx+1);
      dv(idx) = len;
      jcls = reinterpret_cast<jclass> (jni_env->CallObjectMethod (jcls, getComponentType_ID));
      jobj = (len > 0 ? reinterpret_cast<jobjectArray> (jni_env->GetObjectArrayElement (jobj, 0)) : 0);
      idx++;
    }

  restore_fpu_state ();

  return dv;
}

static jobject
make_java_index (JNIEnv* jni_env, const octave_value_list& idx)
{
  jclass_ref ocls (jni_env, jni_env->FindClass ("[I"));
  jobjectArray retval = jni_env->NewObjectArray (idx.length (), ocls, 0);

  for (int i = 0; i < idx.length (); i++)
    {
      idx_vector v = idx(i).index_vector ();

      if (! error_state)
        {
          jintArray_ref i_array (jni_env, jni_env->NewIntArray (v.length ()));
          jint *buf = jni_env->GetIntArrayElements (i_array, 0);

          for (int k = 0; k < v.length (); k++)
            buf[k] = v(k);

          jni_env->ReleaseIntArrayElements (i_array, buf, 0);
          jni_env->SetObjectArrayElement (retval, i, i_array);

          check_exception (jni_env);

          if (error_state)
            break;
        }
      else
        break;
    }

  return retval;
}

static octave_value
get_array_elements (JNIEnv* jni_env, jobject jobj,
                    const octave_value_list& idx)
{
  octave_value retval;
  jobject_ref resObj (jni_env);
  jobject_ref java_idx (jni_env, make_java_index (jni_env, idx));

  if (! error_state)
    {
      jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
      jmethodID mID = jni_env->GetStaticMethodID (helperClass, "arraySubsref", "(Ljava/lang/Object;[[I)Ljava/lang/Object;");
      resObj = jni_env->CallStaticObjectMethod (helperClass, mID, jobj, jobject (java_idx));
    }

  if (resObj)
    retval = box (jni_env, resObj);
  else
    retval = check_exception (jni_env);

  restore_fpu_state ();

  return retval;
}

static octave_value
set_array_elements (JNIEnv* jni_env, jobject jobj,
                    const octave_value_list& idx, const octave_value& rhs)
{
  octave_value retval;

  jclass_ref rhsCls (jni_env);
  jobject_ref resObj (jni_env);
  jobject_ref rhsObj (jni_env);
  jobject_ref java_idx (jni_env, make_java_index (jni_env, idx));

  if (! error_state && unbox (jni_env, rhs, rhsObj, rhsCls))
    {
      jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
      jmethodID mID = jni_env->GetStaticMethodID (helperClass, "arraySubsasgn",
          "(Ljava/lang/Object;[[ILjava/lang/Object;)Ljava/lang/Object;");
      resObj = jni_env->CallStaticObjectMethod (helperClass, mID,
          jobj, jobject (java_idx), jobject (rhsObj));
    }

  if (resObj)
    retval = box (jni_env, resObj);
  else
    retval = check_exception (jni_env);

  restore_fpu_state ();

  return retval;
}

static string_vector
get_invoke_list (JNIEnv* jni_env, jobject jobj)
{
  std::list<std::string> name_list;

  if (jni_env)
    {
      jclass_ref cls (jni_env, jni_env->GetObjectClass (jobj));
      jclass_ref ccls (jni_env, jni_env->GetObjectClass (cls));
      jmethodID getMethods_ID = jni_env->GetMethodID (ccls, "getMethods", "()[Ljava/lang/reflect/Method;");
      jmethodID getFields_ID = jni_env->GetMethodID (ccls, "getFields", "()[Ljava/lang/reflect/Field;");
      jobjectArray_ref mList (jni_env, reinterpret_cast<jobjectArray> (jni_env->CallObjectMethod (cls, getMethods_ID)));
      jobjectArray_ref fList (jni_env, reinterpret_cast<jobjectArray> (jni_env->CallObjectMethod (cls, getFields_ID)));
      int mLen = jni_env->GetArrayLength (mList);
      int fLen = jni_env->GetArrayLength (fList);
      jclass_ref mCls (jni_env, jni_env->FindClass ("java/lang/reflect/Method"));
      jclass_ref fCls (jni_env, jni_env->FindClass ("java/lang/reflect/Field"));
      jmethodID m_getName_ID = jni_env->GetMethodID (mCls, "getName", "()Ljava/lang/String;");
      jmethodID f_getName_ID = jni_env->GetMethodID (fCls, "getName", "()Ljava/lang/String;");

      for (int i = 0; i < mLen; i++)
        {
          jobject_ref meth (jni_env, jni_env->GetObjectArrayElement (mList, i));
          jstring_ref methName (jni_env, reinterpret_cast<jstring> (jni_env->CallObjectMethod (meth, m_getName_ID)));
          name_list.push_back (jstring_to_string (jni_env, methName));
        }

      for (int i = 0; i < fLen; i++)
        {
          jobject_ref field (jni_env, jni_env->GetObjectArrayElement (fList, i));
          jstring_ref fieldName (jni_env, reinterpret_cast<jstring> (jni_env->CallObjectMethod (field, f_getName_ID)));
          name_list.push_back (jstring_to_string (jni_env, fieldName));
        }

      restore_fpu_state ();
    }

  string_vector v (name_list);

  return v.sort (true);
}

static octave_value
convert_to_string (JNIEnv *jni_env, jobject java_object, bool force, char type)
{
  octave_value retval;

  if (jni_env && java_object)
    {
      jclass_ref cls (jni_env, jni_env->FindClass ("java/lang/String"));

      if (jni_env->IsInstanceOf (java_object, cls))
        retval = octave_value (jstring_to_string (jni_env, java_object), type);
      else if (force)
        {
          cls = jni_env->FindClass ("[Ljava/lang/String;");

          if (jni_env->IsInstanceOf (java_object, cls))
            {
              jobjectArray array = reinterpret_cast<jobjectArray> (java_object);
              int len = jni_env->GetArrayLength (array);
              Cell c (len, 1);

              for (int i = 0; i < len; i++)
                {
                  jstring_ref js (jni_env, reinterpret_cast<jstring> (jni_env->GetObjectArrayElement (array, i)));

                  if (js)
                    c(i) = octave_value (jstring_to_string (jni_env, js), type);
                  else
                    {
                      c(i) = check_exception (jni_env);

                      if (error_state)
                        break;
                    }
                }

              retval = octave_value (c);
            }
          else
            {
              cls = jni_env->FindClass ("java/lang/Object");
              jmethodID mID = jni_env->GetMethodID (cls, "toString", "()Ljava/lang/String;");
              jstring_ref js (jni_env, reinterpret_cast<jstring> (jni_env->CallObjectMethod (java_object, mID)));

              if (js)
                retval = octave_value (jstring_to_string (jni_env, js), type);
              else
                retval = check_exception (jni_env);
            }
        }
      else
        error ("unable to convert Java object to string");

      restore_fpu_state ();
    }

  return retval;
}

#define TO_JAVA(obj) dynamic_cast<octave_java*> ((obj).internal_rep ())

octave_value
box (JNIEnv* jni_env, jobject jobj, jclass jcls)
{
  octave_value retval;
  jclass_ref cls (jni_env);

  if (! jobj)
    retval = Matrix ();

  while (retval.is_undefined ())
    {
      // Convert a scalar of any numeric class (byte, short, integer, long,
      // float, double) to a double value.  Matlab does the same thing.
      cls = jni_env->FindClass ("java/lang/Number");
      if (jni_env->IsInstanceOf (jobj, cls))
        {
          jmethodID m = jni_env->GetMethodID (cls, "doubleValue", "()D");
          retval = jni_env->CallDoubleMethod (jobj, m);
          break;
        }

      cls = jni_env->FindClass ("java/lang/Boolean");
      if (jni_env->IsInstanceOf (jobj, cls))
        {
          jmethodID m = jni_env->GetMethodID (cls, "booleanValue", "()Z");
          retval = (jni_env->CallBooleanMethod (jobj, m) ? true : false);
          break;
        }

      cls = jni_env->FindClass ("java/lang/String");
      if (jni_env->IsInstanceOf (jobj, cls))
        {
          retval = jstring_to_string (jni_env, jobj);
          break;
        }

      cls = jni_env->FindClass ("java/lang/Character");
      if (jni_env->IsInstanceOf (jobj, cls))
        {
          jmethodID m = jni_env->GetMethodID (cls, "charValue", "()C");
          retval = jni_env->CallCharMethod (jobj, m);
          retval = retval.convert_to_str (false, true); 
          break;
        }

      if (Vjava_matrix_autoconversion)
        {
          cls = find_octave_class (jni_env, "org/octave/Matrix");

          if (jni_env->IsInstanceOf (jobj, cls))
            {
              jmethodID mID = jni_env->GetMethodID (cls, "getDims", "()[I");
              jintArray_ref iv (jni_env, reinterpret_cast<jintArray> (jni_env->CallObjectMethod (jobj, mID)));
              jint *iv_data = jni_env->GetIntArrayElements (jintArray (iv), 0);
              dim_vector dims;
              dims.resize (jni_env->GetArrayLength (jintArray (iv)));

              for (int i = 0; i < dims.length (); i++)
                dims(i) = iv_data[i];

              jni_env->ReleaseIntArrayElements (jintArray (iv), iv_data, 0);
              mID = jni_env->GetMethodID (cls, "getClassName", "()Ljava/lang/String;");
              jstring_ref js (jni_env, reinterpret_cast<jstring> (jni_env->CallObjectMethod (jobj, mID)));

              std::string s = jstring_to_string (jni_env, js);

              if (s == "double")
                {
                  NDArray m (dims);
                  mID = jni_env->GetMethodID (cls, "toDouble", "()[D");
                  jdoubleArray_ref dv (jni_env, reinterpret_cast<jdoubleArray> (jni_env->CallObjectMethod (jobj, mID)));
                  jni_env->GetDoubleArrayRegion (dv, 0, m.length (), m.fortran_vec ());
                  retval = m;
                  break;
                }
              else if (s == "byte")
                {
                  if (Vjava_unsigned_autoconversion)
                    {
                      uint8NDArray m (dims);
                      mID = jni_env->GetMethodID (cls, "toByte", "()[B");
                      jbyteArray_ref dv (jni_env, reinterpret_cast<jbyteArray> (jni_env->CallObjectMethod (jobj, mID)));
                      jni_env->GetByteArrayRegion (dv, 0, m.length (), reinterpret_cast<jbyte *> (m.fortran_vec ()));
                      retval = m;
                      break;
                    }
                  else
                    {
                      int8NDArray m (dims);
                      mID = jni_env->GetMethodID (cls, "toByte", "()[B");
                      jbyteArray_ref dv (jni_env, reinterpret_cast<jbyteArray> (jni_env->CallObjectMethod (jobj, mID)));
                      jni_env->GetByteArrayRegion (dv, 0, m.length (), reinterpret_cast<jbyte *> (m.fortran_vec ()));
                      retval = m;
                      break;
                    }
                }
              else if (s == "integer")
                {
                  if (Vjava_unsigned_autoconversion)
                    {
                      uint32NDArray m (dims);
                      mID = jni_env->GetMethodID (cls, "toInt", "()[I");
                      jintArray_ref dv (jni_env, reinterpret_cast<jintArray> (jni_env->CallObjectMethod (jobj, mID)));
                      jni_env->GetIntArrayRegion (dv, 0, m.length (), reinterpret_cast<jint *> (m.fortran_vec ()));
                      retval = m;
                      break;
                    }
                  else
                    {
                      int32NDArray m (dims);
                      mID = jni_env->GetMethodID (cls, "toInt", "()[I");
                      jintArray_ref dv (jni_env, reinterpret_cast<jintArray> (jni_env->CallObjectMethod (jobj, mID)));
                      jni_env->GetIntArrayRegion (dv, 0, m.length (), reinterpret_cast<jint *> (m.fortran_vec ()));
                      retval = m;
                      break;
                    }
                }
            }
        }

      cls = find_octave_class (jni_env, "org/octave/OctaveReference");
      if (jni_env->IsInstanceOf (jobj, cls))
        {
          jmethodID mID = jni_env->GetMethodID (cls, "getID", "()I");
          int ID = jni_env->CallIntMethod (jobj, mID);
          std::map<int,octave_value>::iterator it = octave_ref_map.find (ID);

          if (it != octave_ref_map.end ())
            retval = it->second;

          break;
        }

      // No suitable class found.  Return a generic octave_java object
      retval = octave_value (new octave_java (jobj, jcls));
      break;
    }

  return retval;
}

octave_value
box_more (JNIEnv* jni_env, jobject jobj, jclass jcls)
{
  octave_value retval = box (jni_env, jobj, jcls);

  if (retval.is_java ())
    {
      retval = octave_value ();

      jclass_ref cls (jni_env);

      if (retval.is_undefined ())
        {
          cls = jni_env->FindClass ("[D");

          if (jni_env->IsInstanceOf (jobj, cls))
            {
              jdoubleArray jarr = reinterpret_cast<jdoubleArray> (jobj);
              int len = jni_env->GetArrayLength (jarr);

              if (len > 0)
                {
                  Matrix m (1, len);
                  jni_env->GetDoubleArrayRegion (jarr, 0, len, m.fortran_vec ());
                  retval = m;
                }
              else
                retval = Matrix ();
            }
        }

      if (retval.is_undefined ())
        {
          cls = jni_env->FindClass ("[[D");

          if (jni_env->IsInstanceOf (jobj, cls))
            {
              jobjectArray jarr = reinterpret_cast<jobjectArray> (jobj);
              int rows = jni_env->GetArrayLength (jarr), cols = 0;

              if (rows > 0)
                {
                  Matrix m;

                  for (int r = 0; r < rows; r++)
                    {
                      jdoubleArray_ref row (jni_env,
                                            reinterpret_cast<jdoubleArray> (jni_env->GetObjectArrayElement (jarr, r)));

                      if (m.length () == 0)
                        {
                          cols = jni_env->GetArrayLength (row);
                          m.resize (cols, rows);
                        }
                      jni_env->GetDoubleArrayRegion (row, 0, cols, m.fortran_vec () + r * cols);
                    }
                  retval = m.transpose ();
                }
              else
                retval = Matrix ();
            }
        }

      if (retval.is_undefined ())
        {
          cls = jni_env->FindClass ("[Ljava/lang/String;");

          if (jni_env->IsInstanceOf (jobj, cls))
            {
              jobjectArray jarr = reinterpret_cast<jobjectArray> (jobj);
              int len = jni_env->GetArrayLength (jarr);
              Cell m (len, 1);

              for (int i = 0; i < len; i++)
                {
                  jstring_ref js (jni_env,
                                  reinterpret_cast<jstring> (jni_env->GetObjectArrayElement (jarr, i)));
                  m(i) = jstring_to_string (jni_env, js);
                }

              retval = m;
            }
        }
    }

  if (retval.is_undefined ())
    retval = octave_value (new octave_java (jobj, jcls));

  restore_fpu_state ();

  return retval;
}

int
unbox (JNIEnv* jni_env, const octave_value& val, jobject_ref& jobj,
       jclass_ref& jcls)
{
  int found = 1;

  if (val.is_java ())
    {
      octave_java *ovj = TO_JAVA (val);
      jobj = ovj->to_java ();
      jobj.detach ();
      jcls = jni_env->GetObjectClass (jobj);
    }
  else if (val.is_string ())
    {
      std::string s = val.string_value ();

      jobj = jni_env->NewStringUTF (s.c_str ());
      jcls = jni_env->GetObjectClass (jobj);
    }
  else if (val.is_real_scalar ())
    {
      if (val.is_double_type ())
        {
          double dval = val.double_value ();
          jclass_ref dcls (jni_env, jni_env->FindClass ("java/lang/Double"));
          jfieldID fid = jni_env->GetStaticFieldID (dcls, "TYPE", "Ljava/lang/Class;");
          jmethodID mid = jni_env->GetMethodID (dcls, "<init>", "(D)V");
          jcls = reinterpret_cast<jclass> (jni_env->GetStaticObjectField (dcls, fid));
          jobj = jni_env->NewObject (dcls, mid, dval);
        }
      else if (val.is_bool_type ())
        {
          bool bval = val.bool_value ();
          jclass_ref bcls (jni_env, jni_env->FindClass ("java/lang/Boolean"));
          jfieldID fid = jni_env->GetStaticFieldID (bcls, "TYPE", "Ljava/lang/Class;");
          jmethodID mid = jni_env->GetMethodID (bcls, "<init>", "(Z)V");
          jcls = reinterpret_cast<jclass> (jni_env->GetStaticObjectField (bcls, fid));
          jobj = jni_env->NewObject (bcls, mid, bval);
        }
      else
        {
          float fval = val.float_scalar_value ();
          jclass_ref fcls (jni_env, jni_env->FindClass ("java/lang/Float"));
          jfieldID fid = jni_env->GetStaticFieldID (fcls, "TYPE", "Ljava/lang/Class;");
          jmethodID mid = jni_env->GetMethodID (fcls, "<init>", "(F)V");
          jcls = reinterpret_cast<jclass> (jni_env->GetStaticObjectField (fcls, fid));
          jobj = jni_env->NewObject (fcls, mid, fval);
        }
    }
  else if (val.is_integer_type () && val.is_scalar_type ())
    {
      int32_t ival = val.int32_scalar_value ();
      jclass_ref icls (jni_env, jni_env->FindClass ("java/lang/Integer"));
      jfieldID fid = jni_env->GetStaticFieldID (icls, "TYPE", "Ljava/lang/Class;");
      jmethodID mid = jni_env->GetMethodID (icls, "<init>", "(I)V");
      jcls = reinterpret_cast<jclass> (jni_env->GetStaticObjectField (icls, fid));
      jobj = jni_env->NewObject (icls, mid, ival);
    }
  else if (val.is_empty ())
    {
      jobj = 0;
      jcls = 0;
      //jcls = jni_env->FindClass ("java/lang/Object");
    }
  else if (!Vjava_matrix_autoconversion
           && ((val.is_real_matrix ()
                && (val.rows () == 1 || val.columns () == 1))
               || val.is_range ()))
    {
      Matrix m = val.matrix_value ();
      jdoubleArray dv = jni_env->NewDoubleArray (m.length ());
      jni_env->SetDoubleArrayRegion (dv, 0, m.length (), m.fortran_vec ());
      jobj = dv;
      jcls = jni_env->GetObjectClass (jobj);
    }
  else if (Vjava_matrix_autoconversion
           && (val.is_matrix_type () || val.is_range ()) && val.is_real_type ())
    {
      jclass_ref mcls (jni_env, find_octave_class (jni_env, "org/octave/Matrix"));
      dim_vector dims = val.dims ();
      jintArray_ref iv (jni_env, jni_env->NewIntArray (dims.length ()));
      jint *iv_data = jni_env->GetIntArrayElements (jintArray (iv), 0);

      for (int i = 0; i < dims.length (); i++)
        iv_data[i] = dims(i);

      jni_env->ReleaseIntArrayElements (jintArray (iv), iv_data, 0);

      if (val.is_double_type ())
        {
          NDArray m = val.array_value ();
          jdoubleArray_ref dv (jni_env, jni_env->NewDoubleArray (m.length ()));
          jni_env->SetDoubleArrayRegion (jdoubleArray (dv), 0, m.length (),
                                         m.fortran_vec ());
          jmethodID mID = jni_env->GetMethodID (mcls, "<init>", "([D[I)V");
          jobj = jni_env->NewObject (jclass (mcls), mID, jdoubleArray (dv),
                                     jintArray (iv));
          jcls = jni_env->GetObjectClass (jobj);
        }
      else if (val.is_int8_type ())
        {
          int8NDArray m = val.int8_array_value ();
          jbyteArray_ref bv (jni_env, jni_env->NewByteArray (m.length ()));
          jni_env->SetByteArrayRegion (jbyteArray (bv), 0, m.length (),
                                       reinterpret_cast <jbyte *> (m.fortran_vec ()));
          jmethodID mID = jni_env->GetMethodID (mcls, "<init>", "([B[I)V");
          jobj = jni_env->NewObject (jclass (mcls), mID, jbyteArray (bv), jintArray (iv));
          jcls = jni_env->GetObjectClass (jobj);
        }
      else if (val.is_uint8_type ())
        {
          uint8NDArray m = val.uint8_array_value ();
          jbyteArray_ref bv (jni_env, jni_env->NewByteArray (m.length ()));
          jni_env->SetByteArrayRegion (jbyteArray (bv), 0, m.length (),
                                       reinterpret_cast<jbyte *> (m.fortran_vec ()));
          jmethodID mID = jni_env->GetMethodID (mcls, "<init>", "([B[I)V");
          jobj = jni_env->NewObject (jclass (mcls), mID, jbyteArray (bv), jintArray (iv));
          jcls = jni_env->GetObjectClass (jobj);
        }
      else if (val.is_int32_type ())
        {
          int32NDArray m = val.int32_array_value ();
          jintArray_ref v (jni_env, jni_env->NewIntArray (m.length ()));
          jni_env->SetIntArrayRegion (jintArray (v), 0, m.length (),
                                      reinterpret_cast<jint *> (m.fortran_vec ()));
          jmethodID mID = jni_env->GetMethodID (mcls, "<init>", "([I[I)V");
          jobj = jni_env->NewObject (jclass (mcls), mID, jintArray (v), jintArray (iv));
          jcls = jni_env->GetObjectClass (jobj);
        }
      else
        {
          found = 0;
          error ("cannot convert matrix of type '%s'", val.class_name ().c_str ());
        }
    }
  else if (val.is_cellstr ())
    {
      Cell cellStr = val.cell_value ();
      jclass_ref scls (jni_env, jni_env->FindClass ("java/lang/String"));
      jobjectArray array = jni_env->NewObjectArray (cellStr.length (), scls, 0);
      for (int i = 0; i < cellStr.length (); i++)
        {
          jstring_ref jstr (jni_env,
                            jni_env->NewStringUTF (cellStr(i).string_value().c_str ()));
          jni_env->SetObjectArrayElement (array, i, jstr);
        }
      jobj = array;
      jcls = jni_env->GetObjectClass (jobj);
    }
  else
    {
      jclass rcls = find_octave_class (jni_env, "org/octave/OctaveReference");
      jmethodID mID = jni_env->GetMethodID (rcls, "<init>", "(I)V");
      int ID = octave_java_refcount++;

      jobj = jni_env->NewObject (rcls, mID, ID);
      jcls = rcls;
      octave_ref_map[ID] = val;
    }

  return found;
}

int
unbox (JNIEnv* jni_env, const octave_value_list& args,
       jobjectArray_ref& jobjs, jobjectArray_ref& jclss)
{
  int found = 1;

  jclass_ref ocls (jni_env, jni_env->FindClass ("java/lang/Object"));
  jclass_ref ccls (jni_env, jni_env->FindClass ("java/lang/Class"));

  if (! jobjs)
    jobjs = jni_env->NewObjectArray (args.length (), ocls, 0);

  if (! jclss)
    jclss = jni_env->NewObjectArray (args.length (), ccls, 0);

  for (int i = 0; i < args.length (); i++)
    {
      jobject_ref jobj (jni_env);
      jclass_ref jcls (jni_env);

      if (! unbox (jni_env, args(i), jobj, jcls))
        {
          found = 0;
          break;
        }

      jni_env->SetObjectArrayElement (jobjs, i, jobj);
      jni_env->SetObjectArrayElement (jclss, i, jcls);
    }

  return found;
}

static long
get_current_thread_ID (JNIEnv *jni_env)
{
  if (jni_env)
    {
      jclass_ref cls (jni_env, jni_env->FindClass ("java/lang/Thread"));
      jmethodID mID = jni_env->GetStaticMethodID (cls, "currentThread", "()Ljava/lang/Thread;");
      jobject_ref jthread (jni_env, jni_env->CallStaticObjectMethod (cls, mID));

      if (jthread)
        {
          jclass_ref jth_cls (jni_env, jni_env->GetObjectClass (jthread));
          mID = jni_env->GetMethodID (jth_cls, "getId", "()J");
          long result = jni_env->CallLongMethod (jthread, mID);
          //printf ("current java thread ID = %ld\n", result);
          return result;
        }
    }

  return -1;
}

static int
java_event_hook (void)
{
  JNIEnv *current_env = octave_java::thread_jni_env ();

  if (current_env)
    {
      jclass_ref cls (current_env, find_octave_class (current_env, "org/octave/Octave"));
      jmethodID mID = current_env->GetStaticMethodID (cls, "checkPendingAction", "()V");
      current_env->CallStaticVoidMethod (cls, mID);

      restore_fpu_state ();
    }

  return 0;
}

static void
initialize_java (void)
{
  if (! jvm)
    {
      try
        {
          initialize_jvm ();

          JNIEnv *current_env = octave_java::thread_jni_env ();

          command_editor::add_event_hook (java_event_hook);

          octave_thread_ID = get_current_thread_ID (current_env);
          //printf ("octave thread ID=%ld\n", octave_thread_ID);
        }
      catch (std::string msg)
        {
          error (msg.c_str ());
        }

      restore_fpu_state ();
    }
}

JNIEXPORT jboolean JNICALL
Java_org_octave_Octave_call (JNIEnv *env, jclass, jstring funcName,
                             jobjectArray argin, jobjectArray argout)
{
  std::string fname = jstring_to_string (env, funcName);

  int nargout = env->GetArrayLength (argout);
  int nargin = env->GetArrayLength (argin);

  octave_value_list varargin, varargout;

  for (int i = 0; i < nargin; i++)
    varargin(i) = box (env, env->GetObjectArrayElement (argin, i), 0);

  varargout = feval (fname, varargin, nargout);

  if (! error_state)
    {
      jobjectArray_ref out_objs (env, argout), out_clss (env);

      out_objs.detach ();

      if (unbox (env, varargout, out_objs, out_clss))
        return true;
    }

  return false;
}

JNIEXPORT void JNICALL
Java_org_octave_OctaveReference_doFinalize (JNIEnv *, jclass, jint ID)
{
  octave_ref_map.erase (ID);
}

JNIEXPORT void JNICALL
Java_org_octave_Octave_doInvoke (JNIEnv *env, jclass, jint ID,
                                 jobjectArray args)
{
  std::map<int,octave_value>::iterator it = octave_ref_map.find (ID);

  if (it != octave_ref_map.end ())
    {
      octave_value val = it->second;
      int len = env->GetArrayLength (args);
      octave_value_list oct_args;

      for (int i = 0; i < len; i++)
        {
          jobject_ref jobj (env, env->GetObjectArrayElement (args, i));
          oct_args(i) = box (env, jobj, 0);

          if (error_state)
            break;
        }

      if (! error_state)
        {
          BEGIN_INTERRUPT_WITH_EXCEPTIONS;

          if (val.is_function_handle ())
            {
              octave_function *fcn = val.function_value ();
              feval (fcn, oct_args);
            }
          else if (val.is_cell () && val.length () > 0
                   && (val.rows () == 1 || val.columns () == 1)
                   && val.cell_value()(0).is_function_handle ())
            {
              Cell c = val.cell_value ();
              octave_function *fcn = c(0).function_value ();

              for (int i=1; i<c.length (); i++)
                oct_args(len+i-1) = c(i);

              if (! error_state)
                feval (fcn, oct_args);
            }
          else
            error ("trying to invoke non-invocable object");

          END_INTERRUPT_WITH_EXCEPTIONS;
        }
    }
}

JNIEXPORT void JNICALL
Java_org_octave_Octave_doEvalString (JNIEnv *env, jclass, jstring cmd)
{
  std::string s = jstring_to_string (env, cmd);
  int pstatus;
  eval_string (s, false, pstatus, 0);
}

JNIEXPORT jboolean JNICALL
Java_org_octave_Octave_needThreadedInvokation (JNIEnv *env, jclass)
{
  return (get_current_thread_ID (env) != octave_thread_ID);
}

// octave_java class definition

DEFINE_OCTAVE_ALLOCATOR (octave_java);

int octave_java::t_id (-1);

const std::string octave_java::t_name ("octave_java");

void
octave_java::register_type (void)
{
  t_id = octave_value_typeinfo::register_type
         (octave_java::t_name, "<unknown>", octave_value (new octave_java ()));
}

dim_vector
octave_java::dims (void) const
{
  JNIEnv *current_env = thread_jni_env ();

  if (current_env && java_object)
    return compute_array_dimensions (current_env, java_object);
  else
    return dim_vector (1, 1);
}

JNIEnv *
octave_java::thread_jni_env (void)
{
  JNIEnv *env = 0;

  if (jvm)
    jvm->GetEnv (reinterpret_cast<void **> (&env), JNI_VERSION_1_2);

  return env;
}

octave_value_list
octave_java::subsref (const std::string& type,
                      const std::list<octave_value_list>& idx, int nargout)
{
  octave_value_list retval;
  int skip = 1;

  JNIEnv *current_env = thread_jni_env ();

  switch (type[0])
    {
    case '.':
      if (type.length () > 1 && type[1] == '(')
        {
          octave_value_list ovl;
          count++;
          ovl(1) = octave_value (this);
          ovl(0) = (idx.front ())(0);
          std::list<octave_value_list>::const_iterator it = idx.begin ();
          ovl.append (*++it);
          retval = feval (std::string ("javaMethod"), ovl, 1);
          skip++;
        }
      else
        {
          octave_value_list ovl;
          count++;
          ovl(0) = octave_value (this);
          ovl(1) = (idx.front ())(0);
          retval = feval (std::string ("__java_get__"), ovl, 1);
        }
      break;

    case '(':
      if (current_env)
        retval = get_array_elements (current_env, to_java (), idx.front ());
      break;

    default:
      error ("subsref: Java object cannot be indexed with %c", type[0]);
      break;
    }

  if (idx.size () > 1 && type.length () > 1)
    retval = retval(0).next_subsref (nargout, type, idx, skip);

  return retval;
}

octave_value
octave_java::subsasgn (const std::string& type,
                       const std::list<octave_value_list>&idx,
                       const octave_value &rhs)
{
  octave_value retval;

  JNIEnv *current_env = thread_jni_env ();

  switch (type[0])
    {
    case '.':
      if (type.length () == 1)
        {
          // field assignment
          octave_value_list ovl;
          count++;
          ovl(0) = octave_value (this);
          ovl(1) = (idx.front ())(0);
          ovl(2) = rhs;
          feval ("__java_set__", ovl, 0);
          if (! error_state)
            {
              count++;
              retval = octave_value (this);
            }
        }
      else if (type.length () > 2 && type[1] == '(')
        {
          std::list<octave_value_list> new_idx;
          std::list<octave_value_list>::const_iterator it = idx.begin ();
          new_idx.push_back (*it++);
          new_idx.push_back (*it++);
          octave_value_list u = subsref (type.substr (0, 2), new_idx, 1);
          if (! error_state)
            {
              std::list<octave_value_list> next_idx (idx);
              next_idx.erase (next_idx.begin ());
              next_idx.erase (next_idx.begin ());
              u(0).subsasgn (type.substr (2), next_idx, rhs);
              if (! error_state)
                {
                  count++;
                  retval = octave_value (this);
                }
            }
        }
      else if (type[1] == '.')
        {
          octave_value_list u = subsref (type.substr (0, 1), idx, 1);
          if (! error_state)
            {
              std::list<octave_value_list> next_idx (idx);
              next_idx.erase (next_idx.begin ());
              u(0).subsasgn (type.substr (1), next_idx, rhs);
              if (! error_state)
                {
                  count++;
                  retval = octave_value (this);
                }
            }
        }
      else
        error ("invalid indexing/assignment on Java object");
      break;

    case '(':
      if (current_env)
        {
          set_array_elements (current_env, to_java (), idx.front (), rhs);
          if (! error_state)
            {
              count++;
              retval = octave_value (this);
            }
        }
      break;

    default:
      error ("Java object cannot be indexed with %c", type[0]);
      break;
    }

  return retval;
}

string_vector
octave_java::map_keys (void) const
{
  JNIEnv *current_env = thread_jni_env ();

  if (current_env)
    return get_invoke_list (current_env, to_java ());
  else
    return string_vector ();
}

octave_value
octave_java::convert_to_str_internal (bool, bool force, char type) const
{
  JNIEnv *current_env = thread_jni_env ();

  if (current_env)
    return convert_to_string (current_env, to_java (), force, type);
  else
    return octave_value ("");
}

void
octave_java::print (std::ostream& os, bool) const
{
  print_raw (os);
  newline (os);
}

void
octave_java::print_raw (std::ostream& os, bool) const
{
  os << "<Java object: " << java_classname << ">";
}

octave_value
octave_java::do_javaMethod (JNIEnv* jni_env, const std::string& name,
                            const octave_value_list& args)
{
  octave_value retval;

  if (jni_env)
    {
      jobjectArray_ref arg_objs (jni_env), arg_types (jni_env);
      if (unbox (jni_env, args, arg_objs, arg_types))
        {
          jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
          jmethodID mID = jni_env->GetStaticMethodID (helperClass, "invokeMethod",
                                                      "(Ljava/lang/Object;Ljava/lang/String;[Ljava/lang/Object;[Ljava/lang/Class;)Ljava/lang/Object;");
          jstring_ref methName (jni_env, jni_env->NewStringUTF (name.c_str ()));
          jobjectArray_ref resObj (jni_env, reinterpret_cast<jobjectArray> (jni_env->CallStaticObjectMethod (helperClass, mID,
                                                                                                             to_java (), jstring (methName), jobjectArray (arg_objs), jobjectArray (arg_types))));
          if (resObj)
            retval = box (jni_env, resObj);
          else
            retval = check_exception (jni_env);
        }

      restore_fpu_state ();
    }

  return retval;
}

octave_value
octave_java:: do_javaMethod (JNIEnv* jni_env,
                             const std::string& class_name,
                             const std::string& name,
                             const octave_value_list& args)
{
  octave_value retval;

  if (jni_env)
    {
      jobjectArray_ref arg_objs (jni_env), arg_types (jni_env);
      if (unbox (jni_env, args, arg_objs, arg_types))
        {
          jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
          jmethodID mID = jni_env->GetStaticMethodID (helperClass, "invokeStaticMethod",
                                                      "(Ljava/lang/String;Ljava/lang/String;[Ljava/lang/Object;[Ljava/lang/Class;)Ljava/lang/Object;");
          jstring_ref methName (jni_env, jni_env->NewStringUTF (name.c_str ()));
          jstring_ref clsName (jni_env, jni_env->NewStringUTF (class_name.c_str ()));
          jobject_ref resObj (jni_env, jni_env->CallStaticObjectMethod (helperClass, mID,
                                                                        jstring (clsName), jstring (methName), jobjectArray (arg_objs), jobjectArray (arg_types)));
          if (resObj)
            retval = box (jni_env, resObj);
          else
            retval = check_exception (jni_env);
        }

      restore_fpu_state ();
    }

  return retval;
}

octave_value
octave_java::do_javaObject (JNIEnv* jni_env, const std::string& name,
                            const octave_value_list& args)
{
  octave_value retval;

  if (jni_env)
    {
      jobjectArray_ref arg_objs (jni_env), arg_types (jni_env);

      if (unbox (jni_env, args, arg_objs, arg_types))
        {
          jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
          jmethodID mID = jni_env->GetStaticMethodID (helperClass, "invokeConstructor",
                                                      "(Ljava/lang/String;[Ljava/lang/Object;[Ljava/lang/Class;)Ljava/lang/Object;");
          jstring_ref clsName (jni_env, jni_env->NewStringUTF (name.c_str ()));
          jobject_ref resObj (jni_env, jni_env->CallStaticObjectMethod (helperClass, mID,
                                                                        jstring (clsName), jobjectArray (arg_objs), jobjectArray (arg_types)));

          if (resObj)
            retval = octave_value (new octave_java (resObj, 0));
          else
            check_exception (jni_env);
        }

      restore_fpu_state ();
    }

  return retval;
}

octave_value
octave_java::do_java_get (JNIEnv* jni_env, const std::string& name)
{
  octave_value retval;

  if (jni_env)
    {
      jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
      jmethodID mID = jni_env->GetStaticMethodID (helperClass, "getField",
          "(Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object;");
      jstring_ref fName (jni_env, jni_env->NewStringUTF (name.c_str ()));
      jobject_ref resObj (jni_env, jni_env->CallStaticObjectMethod (helperClass, mID,
          to_java (), jstring (fName)));

      if (resObj)
        retval = box (jni_env, resObj);
      else
        retval = check_exception (jni_env);

      restore_fpu_state ();
    }

  return retval;
}

octave_value
octave_java::do_java_get (JNIEnv* jni_env, const std::string& class_name,
                          const std::string& name)
{
  octave_value retval;

  if (jni_env)
    {
      jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
      jmethodID mID = jni_env->GetStaticMethodID (helperClass, "getStaticField",
          "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;");
      jstring_ref cName (jni_env, jni_env->NewStringUTF (class_name.c_str ()));
      jstring_ref fName (jni_env, jni_env->NewStringUTF (name.c_str ()));
      jobject_ref resObj (jni_env, jni_env->CallStaticObjectMethod (helperClass, mID,
          jstring (cName), jstring (fName)));
      if (resObj)
        retval = box (jni_env, resObj);
      else
        retval = check_exception (jni_env);

      restore_fpu_state ();
    }

  return retval;
}

octave_value
octave_java::do_java_set (JNIEnv* jni_env, const std::string& name,
                          const octave_value& val)
{
  octave_value retval;

  if (jni_env)
    {
      jobject_ref jobj (jni_env);
      jclass_ref jcls (jni_env);

      if (unbox (jni_env, val, jobj, jcls))
        {
          jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
          jmethodID mID = jni_env->GetStaticMethodID (helperClass, "setField",
                                                      "(Ljava/lang/Object;Ljava/lang/String;Ljava/lang/Object;)V");
          jstring_ref fName (jni_env, jni_env->NewStringUTF (name.c_str ()));
          jni_env->CallStaticObjectMethod (helperClass, mID, to_java (), jstring (fName), jobject (jobj));
          check_exception (jni_env);
        }

      restore_fpu_state ();
    }

  return retval;
}

octave_value
octave_java::do_java_set (JNIEnv* jni_env, const std::string& class_name,
                          const std::string& name, const octave_value& val)
{
  octave_value retval;

  if (jni_env)
    {
      jobject_ref jobj (jni_env);
      jclass_ref jcls (jni_env);

      if (unbox (jni_env, val, jobj, jcls))
        {
          jclass_ref helperClass (jni_env, find_octave_class (jni_env, "org/octave/ClassHelper"));
          jmethodID mID = jni_env->GetStaticMethodID (helperClass, "setStaticField",
                                                      "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/Object;)V");
          jstring_ref cName (jni_env, jni_env->NewStringUTF (class_name.c_str ()));
          jstring_ref fName (jni_env, jni_env->NewStringUTF (name.c_str ()));
          jni_env->CallStaticObjectMethod (helperClass, mID, jstring (cName), jstring (fName), jobject (jobj));
          check_exception (jni_env);
        }

      restore_fpu_state ();
    }

  return retval;
}

#endif  // endif on HAVE_JAVA

// DEFUN blocks below must be outside of HAVE_JAVA block so that
// documentation strings are always available, even when functions are not.

DEFUN (__java_init__, , ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} java_init ()\n\
Internal function used @strong{only} when debugging Java interface.\n\
Function will directly call initialize_java() to create an instance of a JVM.\n\
@end deftypefn")
{

#ifdef HAVE_JAVA
  octave_value retval;

  retval = 0;

  initialize_java ();

  if (! error_state)
    retval = 1;

  return retval;
#else
  error ("__java_init__: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

DEFUN (__java_exit__, , ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} java_exit ()\n\
Internal function used @strong{only} when debugging Java interface.\n\
Function will directly call terminate_jvm() to destroy the current JVM\n\
instance.\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  terminate_jvm ();
#else
  error ("__java_init__: Octave was not compiled with Java interface");
#endif

  return octave_value ();
}

DEFUN (javaObject, args, ,
       "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{jobj} =} javaObject (@var{classname})\n\
@deftypefnx {Built-in Function} {@var{jobj} =} javaObject (@var{classname}, @var{arg1}, @dots{})\n\
Create a Java object of class @var{classsname}, by calling the class\n\
constructor with the arguments @var{arg1}, @dots{}\n\
\n\
The first example below creates an uninitialized object,\n\
while the second example supplies an initial argument to the constructor.\n\
\n\
@example\n\
@group\n\
x = javaObject (\"java.lang.StringBuffer\")\n\
x = javaObject (\"java.lang.StringBuffer\", \"Initial string\")\n\
@end group\n\
@end example\n\
\n\
@seealso{javaMethod, javaArray}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  octave_value retval;

  initialize_java ();

  if (! error_state)
    {
      JNIEnv *current_env = octave_java::thread_jni_env ();

      if (args.length () > 0)
        {
          std::string classname = args(0).string_value ();
          if (! error_state)
            {
              octave_value_list tmp;
              for (int i=1; i<args.length (); i++)
                tmp(i-1) = args(i);
              retval = octave_java::do_javaObject (current_env, classname, tmp);
            }
          else
            error ("javaObject: CLASSNAME must be a string");
        }
      else
        print_usage ();
    }

  return retval;
#else
  error ("javaObject: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

/*
%!testif HAVE_JAVA
%% The tests below merely check if javaObject works at all. Whether it works
%% properly, i.e. creates the right values, is a matter of Java itself
%% Create a Short and check if it really is a short, i.e. whether it overflows
%! assert (javaObject ("java.lang.Short", 40000).doubleValue < 0);
*/

DEFUN (javaMethod, args, ,
       "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{ret} =} javaMethod (@var{methodname}, @var{obj})\n\
@deftypefnx {Built-in Function} {@var{ret} =} javaMethod (@var{methodname}, @var{obj}, @var{arg1}, @dots{})\n\
Invoke the method @var{methodname} on the Java object @var{obj} with the\n\
arguments @var{arg1}, @dots{}  For static methods, @var{obj} can be a string\n\
representing the fully qualified name of the corresponding class.  The\n\
function returns the result of the method invocation.\n\
\n\
When @var{obj} is a regular Java object, structure-like indexing can be\n\
used as a shortcut syntax.  For instance, the two following statements are\n\
equivalent\n\
\n\
@example\n\
@group\n\
  ret = javaMethod (\"method1\", x, 1.0, \"a string\")\n\
  ret = x.method1 (1.0, \"a string\")\n\
@end group\n\
@end example\n\
\n\
@seealso{methods, javaObject}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  octave_value retval;

  initialize_java ();

  if (! error_state)
    {
      JNIEnv *current_env = octave_java::thread_jni_env ();

      if (args.length () > 1)
        {
          std::string methodname = args(0).string_value ();
          if (! error_state)
            {
              octave_value_list tmp;
              for (int i=2; i<args.length (); i++)
                tmp(i-2) = args(i);

              if (args(1).is_java ())
                {
                  octave_java *jobj = TO_JAVA (args(1));
                  retval = jobj->do_javaMethod (current_env, methodname, tmp);
                }
              else if (args(1).is_string ())
                {
                  std::string cls = args(1).string_value ();
                  retval = octave_java::do_javaMethod (current_env, cls, methodname, tmp);
                }
              else
                error ("javaMethod: OBJ must be a Java object or a string");
            }
          else
            error ("javaMethod: METHODNAME must be a string");
        }
      else
        print_usage ();
    }

  return retval;
#else
  error ("javaMethod: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

/*
%!testif HAVE_JAVA
%% Check for valid first two Java version numbers
%! jver = strsplit (javaMethod ('getProperty', 'java.lang.System', 'java.version'), '.');
%! assert (isfinite (str2double (jver{1})) && isfinite (str2double (jver{2})));
*/

DEFUN (__java_get__, args, ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {@var{val} =} __java_get__ (@var{obj}, @var{name})\n\
Get the value of the field @var{name} of the Java object @var{obj}.  For\n\
static fields, @var{obj} can be a string representing the fully qualified\n\
name of the corresponding class.\n\
\n\
When @var{obj} is a regular Java object, structure-like indexing can be\n\
used as a shortcut syntax.  For instance, the two following statements are\n\
equivalent\n\
\n\
@example\n\
@group\n\
  __java_get__ (x, \"field1\")\n\
  x.field1\n\
@end group\n\
@end example\n\
\n\
@seealso{__java_set__, javaMethod, javaObject}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  octave_value retval;

  initialize_java ();

  if (! error_state)
    {
      JNIEnv *current_env = octave_java::thread_jni_env ();

      if (args.length () == 2)
        {
          std::string name = args(1).string_value ();
          if (! error_state)
            {
              if (args(0).is_java ())
                {
                  octave_java *jobj = TO_JAVA (args(0));
                  retval = jobj->do_java_get (current_env, name);
                }
              else if (args(0).is_string ())
                {
                  std::string cls = args(0).string_value ();
                  retval = octave_java::do_java_get (current_env, cls, name);
                }
              else
                error ("__java_get__: OBJ must be a Java object or a string");
            }
          else
            error ("__java_get__: NAME must be a string");
        }
      else
        print_usage ();
    }

  return retval;
#else
  error ("__java_get__: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

DEFUN (__java_set__, args, ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {@var{obj} =} __java_set__ (@var{obj}, @var{name}, @var{val})\n\
Set the value of the field @var{name} of the Java object @var{obj} to\n\
@var{val}.  For static fields, @var{obj} can be a string representing the\n\
fully qualified named of the corresponding Java class.\n\
\n\
When @var{obj} is a regular Java object, structure-like indexing can be\n\
used as a shortcut syntax.  For instance, the two following statements are\n\
equivalent\n\
\n\
@example\n\
@group\n\
  __java_set__ (x, \"field1\", val)\n\
  x.field1 = val\n\
@end group\n\
@end example\n\
\n\
@seealso{__java_get__, javaMethod, javaObject}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  octave_value retval;

  initialize_java ();

  if (! error_state)
    {
      JNIEnv *current_env = octave_java::thread_jni_env ();

      if (args.length () == 3)
        {
          std::string name = args(1).string_value ();
          if (! error_state)
            {
              if (args(0).is_java ())
                {
                  octave_java *jobj = TO_JAVA (args(0));
                  retval = jobj->do_java_set (current_env, name, args(2));
                }
              else if (args(0).is_string ())
                {
                  std::string cls = args(0).string_value ();
                  retval = octave_java::do_java_set (current_env, cls, name, args(2));
                }
              else
                error ("__java_set__: OBJ must be a Java object or a string");
            }
          else
            error ("__java_set__: NAME must be a string");
        }
      else
        print_usage ();
    }

  return retval;
#else
  error ("__java_set__: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

DEFUN (java2mat, args, ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} java2mat (@var{javaobj})\n\
Undocumented internal function.\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  octave_value_list retval;

  initialize_java ();

  if (! error_state)
    {
      JNIEnv *current_env = octave_java::thread_jni_env ();

      if (args.length () == 1)
        {
          if (args(0).is_java ())
            {
              octave_java *jobj = TO_JAVA (args(0));
              retval(0) = box_more (current_env, jobj->to_java (), 0);
            }
          else
            retval(0) = args(0);
        }
      else
        print_usage ();
    }

  return retval;
#else
  error ("java2mat: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

DEFUN (java_matrix_autoconversion, args, nargout,
       "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} java_matrix_autoconversion ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} java_matrix_autoconversion (@var{new_val})\n\
@deftypefnx {Built-in Function} {} java_matrix_autoconversion (@var{new_val}, \"local\")\n\
Query or set the internal variable that controls whether Java arrays are\n\
automatically converted to Octave matrices.  The default value is false.\n\
\n\
When called from inside a function with the @qcode{\"local\"} option, the\n\
variable is changed locally for the function and any subroutines it calls.  \n\
The original variable value is restored when exiting the function.\n\
@seealso{java_unsigned_autoconversion, debug_java}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  return SET_INTERNAL_VARIABLE (java_matrix_autoconversion);
#else
  error ("java_matrix_autoconversion: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

DEFUN (java_unsigned_autoconversion, args, nargout,
       "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} java_unsigned_autoconversion ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} java_unsigned_autoconversion (@var{new_val})\n\
@deftypefnx {Built-in Function} {} java_unsigned_autoconversion (@var{new_val}, \"local\")\n\
Query or set the internal variable that controls how integer classes are\n\
converted when @code{java_matrix_autoconversion} is enabled.  When enabled,\n\
Java arrays of class Byte or Integer are converted to matrices of class\n\
uint8 or uint32 respectively.  The default value is true.\n\
\n\
When called from inside a function with the @qcode{\"local\"} option, the\n\
variable is changed locally for the function and any subroutines it calls.  \n\
The original variable value is restored when exiting the function.\n\
@seealso{java_matrix_autoconversion, debug_java}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  return SET_INTERNAL_VARIABLE (java_unsigned_autoconversion);
#else
  error ("java_unsigned_autoconversion: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

DEFUN (debug_java, args, nargout,
       "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} debug_java ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} debug_java (@var{new_val})\n\
@deftypefnx {Built-in Function} {} debug_java (@var{new_val}, \"local\")\n\
Query or set the internal variable that determines whether extra debugging\n\
information regarding the initialization of the JVM and any Java exceptions\n\
is printed.\n\
\n\
When called from inside a function with the @qcode{\"local\"} option, the\n\
variable is changed locally for the function and any subroutines it calls.  \n\
The original variable value is restored when exiting the function.\n\
@seealso{java_matrix_autoconversion, java_unsigned_autoconversion}\n\
@end deftypefn")
{
#ifdef HAVE_JAVA
  return SET_INTERNAL_VARIABLE (debug_java);
#else
  error ("debug_java: Octave was not compiled with Java interface");
  return octave_value ();
#endif
}

// Outside of #ifdef HAVE_JAVA because it is desirable to be able to
// test for the presence of a Java object without having Java installed.
DEFUN (isjava, args, ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} isjava (@var{x})\n\
Return true if @var{x} is a Java object.\n\
@seealso{class, typeinfo, isa, javaObject}\n\
@end deftypefn")
{
  octave_value retval;

  if (args.length () != 1)
    print_usage ();
  else
    retval = args(0).is_java ();

  return retval;
}