java plugin: Add an early prototype of a Java binding, similar to the Perl plugin.

It's totally proof-of-concept, but it's possible to dispatch values from
a Java class using the ValueList implementation provided by Doug
MacEachern from Hyperic. The other way around is not yet implemented,
but that's just a matter of time and code. Configuration, notifications,
targets, matches - all that is still missing.

Right now, the code requires JNI version 1.2. Maybe I'll try to
introduce compatibility with JNI 1.1 at a later point, if it's really
useful for somebody.

Signed-off-by: Florian Forster <octo@leeloo.lan.home.verplant.org>

diff --git a/bindings/java/org/collectd/java/CollectdAPI.java b/bindings/java/org/collectd/java/CollectdAPI.java
new file mode 100644 (file)
index 0000000..c6ecca0
--- /dev/null
+++ b/bindings/java/org/collectd/java/CollectdAPI.java
@@ -0,0 +1,31 @@
+/*
+ * collectd - src/java.c
+ * Copyright (C) 2009  Florian octo Forster
+ *
+ * This program 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; only version 2 of the License is applicable.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Florian octo Forster <octo at verplant.org>
+ */
+
+package org.collectd.java;
+
+import org.collectd.protocol.ValueList;
+
+public class CollectdAPI
+{
+  native public static int DispatchValues (ValueList vl);
+} /* class CollectdAPI */
+
+/* vim: set sw=2 sts=2 et fdm=marker : */

diff --git a/bindings/java/org/collectd/protocol/PluginData.java b/bindings/java/org/collectd/protocol/PluginData.java
new file mode 100644 (file)
index 0000000..734a999
--- /dev/null
+++ b/bindings/java/org/collectd/protocol/PluginData.java
@@ -0,0 +1,127 @@
+/*
+ * jcollectd
+ * Copyright (C) 2009 Hyperic, Inc.
+ * 
+ * This program 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; only version 2 of the License is applicable.
+ * 
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+package org.collectd.protocol;
+
+import java.util.Date;
+
+/**
+ * Shared members of value_list_t and notification_t structures.
+ */
+public class PluginData {
+
+    protected long _time;
+    protected String _host;
+    protected String _plugin;
+    protected String _pluginInstance = "";
+    protected String _type = "";
+    protected String _typeInstance = "";
+
+    public PluginData() {
+        
+    }
+
+    public PluginData(PluginData pd) {
+        _time = pd._time;
+        _host = pd._host;
+        _plugin = pd._plugin;
+        _pluginInstance = pd._pluginInstance;
+        _type = pd._type;
+        _typeInstance = pd._typeInstance;
+    }
+
+    public long getTime() {
+        return _time;
+    }
+
+    public void setTime(long time) {
+        _time = time;
+    }
+
+    public String getHost() {
+        return _host;
+    }
+
+    public void setHost(String host) {
+        _host = host;
+    }
+
+    public String getPlugin() {
+        return _plugin;
+    }
+
+    public void setPlugin(String plugin) {
+        _plugin = plugin;
+    }
+
+    public String getPluginInstance() {
+        return _pluginInstance;
+    }
+
+    public void setPluginInstance(String pluginInstance) {
+        _pluginInstance = pluginInstance;
+    }
+
+    public String getType() {
+        return _type;
+    }
+
+    public void setType(String type) {
+        _type = type;
+    }
+
+    public String getTypeInstance() {
+        return _typeInstance;
+    }
+
+    public void setTypeInstance(String typeInstance) {
+        _typeInstance = typeInstance;
+    }
+
+    public boolean defined(String val) {
+        return (val != null) && (val.length() > 0);
+    }
+
+    public String getSource() {
+        final char DLM = '/';
+        StringBuffer sb = new StringBuffer();
+        if (defined(_host)) {
+            sb.append(_host);
+        }
+        if (defined(_plugin)) {
+            sb.append(DLM).append(_plugin);
+        }
+        if (defined(_pluginInstance)) {
+            sb.append(DLM).append(_pluginInstance);
+        }
+        if (defined(_type)) {
+            sb.append(DLM).append(_type);
+        }
+        if (defined(_typeInstance)) {
+            sb.append(DLM).append(_typeInstance);
+        }
+        return sb.toString();        
+    }
+
+    public String toString() {
+        StringBuffer sb = new StringBuffer();
+        sb.append('[').append(new Date(_time)).append("] ");
+        sb.append(getSource());
+        return sb.toString();
+    }
+}

diff --git a/bindings/java/org/collectd/protocol/ValueList.java b/bindings/java/org/collectd/protocol/ValueList.java
new file mode 100644 (file)
index 0000000..7ae2d3d
--- /dev/null
+++ b/bindings/java/org/collectd/protocol/ValueList.java
@@ -0,0 +1,105 @@
+/*
+ * jcollectd
+ * Copyright (C) 2009 Hyperic, Inc.
+ * 
+ * This program 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; only version 2 of the License is applicable.
+ * 
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+package org.collectd.protocol;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Java representation of collectd/src/plugin.h:value_list_t structure.
+ */
+public class ValueList extends PluginData {
+
+    List<Number> _values = new ArrayList<Number>();
+    List<DataSource> _ds = new ArrayList<DataSource>();
+
+    long _interval;
+
+    public ValueList() {
+        
+    }
+
+    public ValueList(PluginData pd) {
+        super(pd);
+    }
+
+    public ValueList(ValueList vl) {
+        this((PluginData)vl);
+        _interval = vl._interval;
+        _values.addAll(vl.getValues());
+        _ds.addAll(vl._ds);
+    }
+
+    public List<Number> getValues() {
+        return _values;
+    }
+
+    public void setValues(List<Number> values) {
+        _values = values;
+    }
+
+    public void addValue(Number value) {
+        _values.add(value);
+    }
+
+    public List<DataSource> getDataSource() {
+        if (_ds.size() > 0) {
+            return _ds;
+        }
+        else {
+            TypesDB db = TypesDB.getInstance();
+            return db.getType(_type);
+        }
+    }
+
+    public void setDataSource(List<DataSource> ds) {
+        _ds = ds;
+    }
+
+    public long getInterval() {
+        return _interval;
+    }
+
+    public void setInterval(long interval) {
+        _interval = interval;
+    }
+
+    public String toString() {
+        StringBuffer sb = new StringBuffer(super.toString());
+        sb.append("=[");
+        List<DataSource> ds = getDataSource();
+        int size = _values.size();
+        for (int i=0; i<size; i++) {
+            Number val = _values.get(i);
+            String name;
+            if (ds == null) {
+                name = "unknown" + i;
+            }
+            else {
+                name = ds.get(i).getName();
+            }
+            sb.append(name).append('=').append(val);
+            if (i < size-1) {
+                sb.append(',');
+            }
+        }
+        sb.append("]");
+        return sb.toString();
+    }
+}

diff --git a/configure.in b/configure.in
index 9a467d8f3d30d37a956d06236eb58eb21db086a5..5ff8fc82c8da7f12d67326f786c26dca0148b6e6 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1254,6 +1254,96 @@ then
 fi
 # }}}
 
+# --with-java {{{
+with_java_home="$JAVA_HOME"
+with_java_vmtype="client"
+with_java_cflags=""
+with_java_libs=""
+AC_ARG_WITH(java, [AS_HELP_STRING([--with-java@<:@=PREFIX@:>@], [Path to Java home.])],
+[
+       if test "x$withval" = "xno"
+       then
+               with_java="no"
+       else if test "x$withval" = "xyes"
+       then
+               with_java="yes"
+       else
+               with_java_home="$withval"
+               with_java="yes"
+       fi; fi
+],
+[with_java="yes"])
+if test "x$with_java" = "xyes"
+then
+       if test -d "$with_java_home"
+       then
+               if test -d "$with_java_home/include"
+               then
+                       JAVA_CPPFLAGS="$JAVA_CPPFLAGS -I$with_java_home/include"
+               else
+                       JAVA_CPPFLAGS="$JAVA_CPPFLAGS -I$with_java_home"
+               fi
+               
+               if test -d "$with_java_home/lib"
+               then
+                       JAVA_LDFLAGS="$JAVA_LDFLAGS -L$with_java_home/lib"
+               else
+                       JAVA_LDFLAGS="$JAVA_LDFLAGS -L$with_java_home"
+               fi
+       else if test "x$with_java_home" != "x"
+       then
+               AC_MSG_WARN([JAVA_HOME: No such directory: $with_java_home])
+       fi; fi
+fi
+
+if test "x$JAVA_CPPFLAGS" != "x"
+then
+       AC_MSG_NOTICE([Building with JAVA_CPPFLAGS set to: $JAVA_CPPFLAGS])
+fi
+if test "x$JAVA_CFLAGS" != "x"
+then
+       AC_MSG_NOTICE([Building with JAVA_CFLAGS set to: $JAVA_CFLAGS])
+fi
+if test "x$JAVA_LDFLAGS" != "x"
+then
+       AC_MSG_NOTICE([Building with JAVA_LDFLAGS set to: $JAVA_LDFLAGS])
+fi
+
+SAVE_CPPFLAGS="$CPPFLAGS"
+SAVE_CFLAGS="$CFLAGS"
+SAVE_LDFLAGS="$LDFLAGS"
+CPPFLAGS="$CPPFLAGS $JAVA_CPPFLAGS"
+CFLAGS="$CFLAGS $JAVA_CFLAGS"
+LDFLAGS="$LDFLAGS $JAVA_LDFLAGS"
+
+if test "x$with_java" = "xyes"
+then
+       AC_CHECK_HEADERS(jni.h, [], [with_java="no (jni.h not found)"])
+fi
+if test "x$with_java" = "xyes"
+then
+       AC_CHECK_LIB(jvm, JNI_CreateJavaVM,
+       [with_java="yes"],
+       [with_java="no (libjvm not found)"],
+       [$JAVA_LIBS])
+fi
+if test "x$with_java" = "xyes"
+then
+       JAVA_LIBS="$JAVA_LIBS -ljvm"
+       AC_MSG_NOTICE([Building with JAVA_LIBS set to: $JAVA_LIBS])
+fi
+
+CPPFLAGS="$SAVE_CPPFLAGS"
+CFLAGS="$SAVE_CFLAGS"
+LDFLAGS="$SAVE_LDFLAGS"
+
+AC_SUBST(JAVA_CPPFLAGS)
+AC_SUBST(JAVA_CFLAGS)
+AC_SUBST(JAVA_LDFLAGS)
+AC_SUBST(JAVA_LIBS)
+AM_CONDITIONAL(BUILD_WITH_JAVA, test "x$with_java" = "xyes")
+# }}}
+
 # --with-libmysql {{{
 with_mysql_config="mysql_config"
 with_mysql_cflags=""
@@ -3134,6 +3224,7 @@ AC_PLUGIN([ipmi],        [$plugin_ipmi],       [IPMI sensor statistics])
 AC_PLUGIN([iptables],    [$with_libiptc],      [IPTables rule counters])
 AC_PLUGIN([ipvs],        [$plugin_ipvs],       [IPVS connection statistics])
 AC_PLUGIN([irq],         [$plugin_irq],        [IRQ statistics])
+AC_PLUGIN([java],        [$with_java],         [Embed the Java Virtual Machine])
 AC_PLUGIN([libvirt],     [$plugin_libvirt],    [Virtual machine statistics])
 AC_PLUGIN([load],        [$plugin_load],       [System load])
 AC_PLUGIN([logfile],     [yes],                [File logging plugin])
@@ -3279,6 +3370,7 @@ Configuration:
     libesmtp  . . . . . . $with_libesmtp
     libiokit  . . . . . . $with_libiokit
     libiptc . . . . . . . $with_libiptc
+    libjvm  . . . . . . . $with_java
     libkstat  . . . . . . $with_kstat
     libkvm  . . . . . . . $with_libkvm
     libmysql  . . . . . . $with_libmysql
@@ -3334,6 +3426,7 @@ Configuration:
     iptables  . . . . . . $enable_iptables
     ipvs  . . . . . . . . $enable_ipvs
     irq . . . . . . . . . $enable_irq
+    java  . . . . . . . . $enable_java
     libvirt . . . . . . . $enable_libvirt
     load  . . . . . . . . $enable_load
     logfile . . . . . . . $enable_logfile

diff --git a/src/Makefile.am b/src/Makefile.am
index 39e0c416d4db3ccca6613ebb607b85cf8c551e92..ba304fb1fce73f3b142c1e66626164e357f3c5f5 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -378,6 +378,17 @@ collectd_LDADD += "-dlopen" irq.la
 collectd_DEPENDENCIES += irq.la
 endif
 
+if BUILD_PLUGIN_JAVA
+pkglib_LTLIBRARIES += java.la
+java_la_SOURCES = java.c
+java_la_CPPFLAGS = $(AM_CPPFLAGS) $(JAVA_CPPFLAGS)
+java_la_CFLAGS = $(AM_CFLAGS) $(JAVA_CFLAGS)
+java_la_LDFLAGS = -module -avoid-version $(JAVA_LDFLAGS)
+java_la_LIBADD = $(JAVA_LIBS)
+collectd_LDADD += "-dlopen" java.la
+collectd_DEPENDENCIES += java.la
+endif
+
 if BUILD_PLUGIN_LIBVIRT
 pkglib_LTLIBRARIES += libvirt.la
 libvirt_la_SOURCES = libvirt.c

diff --git a/src/java.c b/src/java.c
new file mode 100644 (file)
index 0000000..e2a04e1
--- /dev/null
+++ b/src/java.c
@@ -0,0 +1,678 @@
+/**
+ * collectd - src/java.c
+ * Copyright (C) 2009  Florian octo Forster
+ * Copyright (C) 2008  Justo Alonso Achaques
+ *
+ * This program 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; only version 2 of the License is applicable.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Florian octo Forster <octo at verplant.org>
+ *   Justo Alonso Achaques <justo.alonso at gmail.com>
+ **/
+
+#include "collectd.h"
+#include "plugin.h"
+#include "common.h"
+
+#include <pthread.h>
+#include <jni.h>
+
+#if !defined(JNI_VERSION_1_2)
+# error "Need JNI 1.2 compatible interface!"
+#endif
+
+/*
+ * Types
+ */
+struct java_plugin_s /* {{{ */
+{
+  char *class_name;
+  jclass class_ptr;
+  jobject object_ptr;
+
+#define CJNI_FLAG_ENABLED 0x0001
+  int flags;
+
+  jmethodID method_init;
+  jmethodID method_read;
+  jmethodID method_shutdown;
+};
+typedef struct java_plugin_s java_plugin_t;
+/* }}} */
+
+/*
+ * Global variables
+ */
+static JavaVM *jvm = NULL;
+
+static java_plugin_t java_plugins[] =
+{
+  { "org.collectd.java.Foobar", NULL, NULL, 0, NULL, NULL, NULL }
+};
+static size_t java_plugins_num = sizeof (java_plugins) / sizeof (java_plugins[0]);
+
+/* 
+ * Conversion functons
+ *
+ * - jtoc_*: From Java to C
+ * - ctoj_*: From C to Java
+ */
+static int jtoc_string (JNIEnv *jvm_env, /* {{{ */
+    char *buffer, size_t buffer_size,
+    jclass class_ptr, jobject object_ptr, const char *method_name)
+{
+  jmethodID method_id;
+  jobject string_obj;
+  const char *c_str;
+
+  method_id = (*jvm_env)->GetMethodID (jvm_env, class_ptr,
+      method_name, "()Ljava/lang/String;");
+  if (method_id == NULL)
+  {
+    ERROR ("java plugin: jtoc_string: Cannot find method `String %s ()'.",
+        method_name);
+    return (-1);
+  }
+
+  string_obj = (*jvm_env)->CallObjectMethod (jvm_env, object_ptr, method_id);
+  if (string_obj == NULL)
+  {
+    ERROR ("java plugin: jtoc_string: CallObjectMethod (%s) failed.",
+        method_name);
+    return (-1);
+  }
+
+  c_str = (*jvm_env)->GetStringUTFChars (jvm_env, string_obj, 0);
+  if (c_str == NULL)
+  {
+    ERROR ("java plugin: jtoc_string: GetStringUTFChars failed.");
+    (*jvm_env)->DeleteLocalRef (jvm_env, string_obj);
+    return (-1);
+  }
+
+  DEBUG ("java plugin: jtoc_string: ->%s() = %s", method_name, c_str);
+
+  sstrncpy (buffer, c_str, buffer_size);
+
+  (*jvm_env)->ReleaseStringUTFChars (jvm_env, string_obj, c_str);
+  (*jvm_env)->DeleteLocalRef (jvm_env, string_obj);
+
+  return (0);
+} /* }}} int jtoc_string */
+
+static int jtoc_long (JNIEnv *jvm_env, /* {{{ */
+    jlong *ret_value,
+    jclass class_ptr, jobject object_ptr, const char *method_name)
+{
+  jmethodID method_id;
+
+  method_id = (*jvm_env)->GetMethodID (jvm_env, class_ptr,
+      method_name, "()J");
+  if (method_id == NULL)
+  {
+    ERROR ("java plugin: jtoc_string: Cannot find method `long %s ()'.",
+        method_name);
+    return (-1);
+  }
+
+  *ret_value = (*jvm_env)->CallLongMethod (jvm_env, object_ptr, method_id);
+
+  DEBUG ("java plugin: jtoc_long: ->%s() = %li",
+      method_name, (long int) *ret_value);
+
+  return (0);
+} /* }}} int jtoc_long */
+
+static int jtoc_double (JNIEnv *jvm_env, /* {{{ */
+    jdouble *ret_value,
+    jclass class_ptr, jobject object_ptr, const char *method_name)
+{
+  jmethodID method_id;
+
+  method_id = (*jvm_env)->GetMethodID (jvm_env, class_ptr,
+      method_name, "()D");
+  if (method_id == NULL)
+  {
+    ERROR ("java plugin: jtoc_string: Cannot find method `double %s ()'.",
+        method_name);
+    return (-1);
+  }
+
+  *ret_value = (*jvm_env)->CallDoubleMethod (jvm_env, object_ptr, method_id);
+
+  DEBUG ("java plugin: jtoc_double: ->%s() = %g",
+      method_name, (double) *ret_value);
+
+  return (0);
+} /* }}} int jtoc_double */
+
+static int jtoc_value (JNIEnv *jvm_env, /* {{{ */
+    value_t *ret_value, int ds_type, jobject object_ptr)
+{
+  jclass class_ptr;
+  int status;
+
+  class_ptr = (*jvm_env)->GetObjectClass (jvm_env, object_ptr);
+
+  if (ds_type == DS_TYPE_COUNTER)
+  {
+    jlong tmp_long;
+
+    status = jtoc_long (jvm_env, &tmp_long,
+        class_ptr, object_ptr, "longValue");
+    if (status != 0)
+    {
+      ERROR ("java plugin: jtoc_value: "
+          "jtoc_long failed.");
+      return (-1);
+    }
+    (*ret_value).counter = (counter_t) tmp_long;
+  }
+  else
+  {
+    jdouble tmp_double;
+
+    status = jtoc_double (jvm_env, &tmp_double,
+        class_ptr, object_ptr, "doubleValue");
+    if (status != 0)
+    {
+      ERROR ("java plugin: jtoc_value: "
+          "jtoc_double failed.");
+      return (-1);
+    }
+    (*ret_value).gauge = (gauge_t) tmp_double;
+  }
+
+  return (0);
+} /* }}} int jtoc_value */
+
+static int jtoc_values_array (JNIEnv *jvm_env, /* {{{ */
+    const data_set_t *ds, value_list_t *vl,
+    jclass class_ptr, jobject object_ptr)
+{
+  jmethodID m_getvalues;
+  jmethodID m_toarray;
+  jobject o_list;
+  jobjectArray o_number_array;
+
+  value_t *values;
+  int values_num;
+  int i;
+
+  values_num = ds->ds_num;
+
+  values = NULL;
+  o_number_array = NULL;
+  o_list = NULL;
+
+#define BAIL_OUT(status) \
+  free (values); \
+  if (o_number_array != NULL) \
+    (*jvm_env)->DeleteLocalRef (jvm_env, o_number_array); \
+  if (o_list != NULL) \
+    (*jvm_env)->DeleteLocalRef (jvm_env, o_list); \
+  return (status);
+
+  /* Call: List<Number> ValueList.getValues () */
+  m_getvalues = (*jvm_env)->GetMethodID (jvm_env, class_ptr,
+      "getValues", "()Ljava/util/List;");
+  if (m_getvalues == NULL)
+  {
+    ERROR ("java plugin: jtoc_values_array: "
+        "Cannot find method `List getValues ()'.");
+    BAIL_OUT (-1);
+  }
+
+  o_list = (*jvm_env)->CallObjectMethod (jvm_env, object_ptr, m_getvalues);
+  if (o_list == NULL)
+  {
+    ERROR ("java plugin: jtoc_values_array: "
+        "CallObjectMethod (getValues) failed.");
+    BAIL_OUT (-1);
+  }
+
+  /* Call: Number[] List.toArray () */
+  m_toarray = (*jvm_env)->GetMethodID (jvm_env,
+      (*jvm_env)->GetObjectClass (jvm_env, o_list),
+      "toArray", "()[Ljava/lang/Object;");
+  if (m_toarray == NULL)
+  {
+    ERROR ("java plugin: jtoc_values_array: "
+        "Cannot find method `Object[] toArray ()'.");
+    BAIL_OUT (-1);
+  }
+
+  o_number_array = (*jvm_env)->CallObjectMethod (jvm_env, o_list, m_toarray);
+  if (o_number_array == NULL)
+  {
+    ERROR ("java plugin: jtoc_values_array: "
+        "CallObjectMethod (toArray) failed.");
+    BAIL_OUT (-1);
+  }
+
+  values = calloc (values_num, sizeof (value_t));
+  if (values == NULL)
+  {
+    ERROR ("java plugin: jtoc_values_array: calloc failed.");
+    BAIL_OUT (-1);
+  }
+
+  for (i = 0; i < values_num; i++)
+  {
+    jobject o_number;
+    int status;
+
+    o_number = (*jvm_env)->GetObjectArrayElement (jvm_env,
+        o_number_array, (jsize) i);
+    if (o_number == NULL)
+    {
+      ERROR ("java plugin: jtoc_values_array: "
+          "GetObjectArrayElement (%i) failed.", i);
+      BAIL_OUT (-1);
+    }
+
+    status = jtoc_value (jvm_env, values + i, ds->ds[i].type, o_number);
+    if (status != 0)
+    {
+      ERROR ("java plugin: jtoc_values_array: "
+          "jtoc_value (%i) failed.", i);
+      BAIL_OUT (-1);
+    }
+  } /* for (i = 0; i < values_num; i++) */
+
+  vl->values = values;
+  vl->values_len = values_num;
+
+#undef BAIL_OUT
+  (*jvm_env)->DeleteLocalRef (jvm_env, o_number_array);
+  (*jvm_env)->DeleteLocalRef (jvm_env, o_list);
+  return (0);
+} /* }}} int jtoc_values_array */
+
+static int jtoc_value_list (JNIEnv *jvm_env, value_list_t *vl, /* {{{ */
+    jobject object_ptr)
+{
+  jclass class_ptr;
+  int status;
+  jlong tmp_long;
+  const data_set_t *ds;
+
+  class_ptr = (*jvm_env)->GetObjectClass (jvm_env, object_ptr);
+  if (class_ptr == NULL)
+  {
+    ERROR ("java plugin: jtoc_value_list: GetObjectClass failed.");
+    return (-1);
+  }
+
+#define SET_STRING(buffer,method) do { \
+  status = jtoc_string (jvm_env, buffer, sizeof (buffer), \
+      class_ptr, object_ptr, method); \
+  if (status != 0) { \
+    ERROR ("java plugin: jtoc_value_list: jtoc_string (%s) failed.", \
+        method); \
+    return (-1); \
+  } } while (0)
+
+  SET_STRING(vl->type, "getType");
+
+  ds = plugin_get_ds (vl->type);
+  if (ds == NULL)
+  {
+    ERROR ("java plugin: jtoc_value_list: Data-set `%s' is not defined. "
+        "Please consult the types.db(5) manpage for mor information.",
+        vl->type);
+    return (-1);
+  }
+
+  SET_STRING(vl->host, "getHost");
+  SET_STRING(vl->plugin, "getPlugin");
+  SET_STRING(vl->plugin_instance, "getPluginInstance");
+  SET_STRING(vl->type_instance, "getTypeInstance");
+
+#undef SET_STRING
+
+  status = jtoc_long (jvm_env, &tmp_long, class_ptr, object_ptr, "getTime");
+  if (status != 0)
+  {
+    ERROR ("java plugin: jtoc_value_list: jtoc_string (getTime) failed.");
+    return (-1);
+  }
+  vl->time = (time_t) tmp_long;
+
+  status = jtoc_long (jvm_env, &tmp_long,
+      class_ptr, object_ptr, "getInterval");
+  if (status != 0)
+  {
+    ERROR ("java plugin: jtoc_value_list: jtoc_string (getInterval) failed.");
+    return (-1);
+  }
+  vl->interval = (int) tmp_long;
+
+  status = jtoc_values_array (jvm_env, ds, vl, class_ptr, object_ptr);
+  if (status != 0)
+  {
+    ERROR ("java plugin: jtoc_value_list: jtoc_values_array failed.");
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int jtoc_value_list */
+
+/* 
+ * Functions accessible from Java
+ */
+static jint JNICALL cjni_api_dispatch_values (JNIEnv *jvm_env, /* {{{ */
+    jobject this, jobject java_vl)
+{
+  value_list_t vl = VALUE_LIST_INIT;
+  int status;
+
+  DEBUG ("cjni_api_dispatch_values: java_vl = %p;", (void *) java_vl);
+
+  status = jtoc_value_list (jvm_env, &vl, java_vl);
+  if (status != 0)
+  {
+    ERROR ("java plugin: cjni_api_dispatch_values: jtoc_value_list failed.");
+    return (-1);
+  }
+
+  plugin_dispatch_values (&vl);
+
+  sfree (vl.values);
+
+  return (0);
+} /* }}} jint cjni_api_dispatch_values */
+
+static JNINativeMethod jni_api_functions[] =
+{
+  { "DispatchValues", "(Lorg/collectd/protocol/ValueList;)I", cjni_api_dispatch_values }
+};
+static size_t jni_api_functions_num = sizeof (jni_api_functions)
+  / sizeof (jni_api_functions[0]);
+
+/*
+ * Functions
+ */
+static int cjni_init_one_plugin (JNIEnv *jvm_env, java_plugin_t *jp) /* {{{ */
+{
+  jmethodID constructor_id;
+  int status;
+
+  jp->class_ptr = (*jvm_env)->FindClass (jvm_env, jp->class_name);
+  if (jp->class_ptr == NULL)
+  {
+    ERROR ("cjni_init_one_plugin: FindClass (%s) failed.",
+        jp->class_name);
+    return (-1);
+  }
+
+  constructor_id = (*jvm_env)->GetMethodID (jvm_env, jp->class_ptr,
+      "<init>", "()V");
+  if (constructor_id == NULL)
+  {
+    ERROR ("cjni_init_one_plugin: Could not find the constructor for `%s'.",
+        jp->class_name);
+    return (-1);
+  }
+
+  jp->object_ptr = (*jvm_env)->NewObject (jvm_env, jp->class_ptr,
+      constructor_id);
+  if (jp->object_ptr == NULL)
+  {
+    ERROR ("cjni_init_one_plugin: Could create a new `%s' object.",
+        jp->class_name);
+    return (-1);
+  }
+
+  jp->method_init = (*jvm_env)->GetMethodID (jvm_env, jp->class_ptr,
+      "Init", "()I");
+  DEBUG ("jp->method_init = %p;", (void *) jp->method_init);
+  jp->method_read = (*jvm_env)->GetMethodID (jvm_env, jp->class_ptr,
+      "Read", "()I");
+  DEBUG ("jp->method_read = %p;", (void *) jp->method_read);
+  jp->method_shutdown = (*jvm_env)->GetMethodID (jvm_env, jp->class_ptr,
+      "Shutdown", "()I");
+  DEBUG ("jp->method_shutdown = %p;", (void *) jp->method_shutdown);
+
+  status = (*jvm_env)->CallIntMethod (jvm_env, jp->object_ptr,
+      jp->method_init);
+  if (status != 0)
+  {
+    ERROR ("cjni_init_one_plugin: Initializing `%s' object failed "
+        "with status %i.", jp->class_name, status);
+    return (-1);
+  }
+  jp->flags |= CJNI_FLAG_ENABLED;
+
+  return (0);
+} /* }}} int cjni_init_one_plugin */
+
+static int cjni_init_plugins (JNIEnv *jvm_env) /* {{{ */
+{
+  size_t j;
+
+  for (j = 0; j < java_plugins_num; j++)
+    cjni_init_one_plugin (jvm_env, &java_plugins[j]);
+
+  return (0);
+} /* }}} int cjni_init_plugins */
+
+static int cjni_init_native (JNIEnv *jvm_env) /* {{{ */
+{
+  jclass api_class_ptr;
+  int status;
+
+  api_class_ptr = (*jvm_env)->FindClass (jvm_env, "org.collectd.java.CollectdAPI");
+  if (api_class_ptr == NULL)
+  {
+    ERROR ("cjni_init_native: Cannot find API class `org.collectd.java.CollectdAPI'.");
+    return (-1);
+  }
+
+  status = (*jvm_env)->RegisterNatives (jvm_env, api_class_ptr,
+      jni_api_functions, (jint) jni_api_functions_num);
+  if (status != 0)
+  {
+    ERROR ("cjni_init_native: RegisterNatives failed with status %i.", status);
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cjni_init_native */
+
+static int cjni_init (void) /* {{{ */
+{
+  JNIEnv *jvm_env;
+  JavaVMInitArgs vm_args;
+  JavaVMOption vm_options[2];
+
+  int status;
+
+  if (jvm != NULL)
+    return (0);
+
+  jvm_env = NULL;
+
+  memset (&vm_args, 0, sizeof (vm_args));
+  vm_args.version = JNI_VERSION_1_2;
+  vm_args.options = vm_options;
+  vm_args.nOptions = sizeof (vm_options) / sizeof (vm_options[0]);
+
+  vm_args.options[0].optionString = "-verbose:jni";
+  vm_args.options[1].optionString = "-Djava.class.path=/home/octo/collectd/bindings/java";
+
+  status = JNI_CreateJavaVM (&jvm, (void **) &jvm_env, (void **) &vm_args);
+  if (status != 0)
+  {
+    ERROR ("cjni_init: JNI_CreateJavaVM failed with status %i.",
+       status);
+    return (-1);
+  }
+  assert (jvm != NULL);
+  assert (jvm_env != NULL);
+
+  /* Call RegisterNatives */
+  status = cjni_init_native (jvm_env);
+  if (status != 0)
+  {
+    ERROR ("cjni_init: cjni_init_native failed.");
+    return (-1);
+  }
+
+  cjni_init_plugins (jvm_env);
+
+  return (0);
+} /* }}} int cjni_init */
+
+static int cjni_read_one_plugin (JNIEnv *jvm_env, java_plugin_t *jp) /* {{{ */
+{
+  int status;
+
+  if ((jp == NULL)
+      || ((jp->flags & CJNI_FLAG_ENABLED) == 0)
+      || (jp->method_read == NULL))
+    return (0);
+
+  DEBUG ("java plugin: Calling: %s.Read()", jp->class_name);
+
+  status = (*jvm_env)->CallIntMethod (jvm_env, jp->object_ptr,
+      jp->method_read);
+  if (status != 0)
+  {
+    ERROR ("cjni_read_one_plugin: Calling `Read' on an `%s' object failed "
+        "with status %i.", jp->class_name, status);
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cjni_read_one_plugin */
+
+static int cjni_read_plugins (JNIEnv *jvm_env) /* {{{ */
+{
+  size_t j;
+
+  for (j = 0; j < java_plugins_num; j++)
+    cjni_read_one_plugin (jvm_env, &java_plugins[j]);
+
+  return (0);
+} /* }}} int cjni_read_plugins */
+
+static int cjni_read (void) /* {{{ */
+{
+  JNIEnv *jvm_env;
+  JavaVMAttachArgs args;
+  int status;
+
+  if (jvm == NULL)
+  {
+    ERROR ("java plugin: cjni_read: jvm == NULL");
+    return (-1);
+  }
+
+  jvm_env = NULL;
+  memset (&args, 0, sizeof (args));
+  args.version = JNI_VERSION_1_2;
+
+  status = (*jvm)->AttachCurrentThread (jvm, (void **) &jvm_env, &args);
+  if (status != 0)
+  {
+    ERROR ("java plugin: cjni_read: AttachCurrentThread failed with status %i.",
+        status);
+    return (-1);
+  }
+
+  cjni_read_plugins (jvm_env);
+
+  status = (*jvm)->DetachCurrentThread (jvm);
+  if (status != 0)
+  {
+    ERROR ("java plugin: cjni_read: DetachCurrentThread failed with status %i.",
+        status);
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cjni_read */
+
+static int cjni_shutdown_one_plugin (JNIEnv *jvm_env, /* {{{ */
+    java_plugin_t *jp)
+{
+  int status;
+
+  if ((jp == NULL)
+      || ((jp->flags & CJNI_FLAG_ENABLED) == 0)
+      || (jp->method_shutdown == NULL))
+    return (0);
+
+  status = (*jvm_env)->CallIntMethod (jvm_env, jp->object_ptr,
+      jp->method_shutdown);
+  if (status != 0)
+  {
+    ERROR ("cjni_shutdown_one_plugin: Destroying an `%s' object failed "
+        "with status %i.", jp->class_name, status);
+    return (-1);
+  }
+  jp->flags &= ~CJNI_FLAG_ENABLED;
+
+  return (0);
+} /* }}} int cjni_shutdown_one_plugin */
+
+static int cjni_shutdown_plugins (JNIEnv *jvm_env) /* {{{ */
+{
+  size_t j;
+
+  for (j = 0; j < java_plugins_num; j++)
+    cjni_shutdown_one_plugin (jvm_env, &java_plugins[j]);
+
+  return (0);
+} /* }}} int cjni_shutdown_plugins */
+
+static int cjni_shutdown (void) /* {{{ */
+{
+  JNIEnv *jvm_env;
+  JavaVMAttachArgs args;
+  int status;
+
+  if (jvm == NULL)
+    return (0);
+
+  jvm_env = NULL;
+  memset (&args, 0, sizeof (args));
+  args.version = JNI_VERSION_1_2;
+
+  status = (*jvm)->AttachCurrentThread (jvm, (void **) &jvm_env, &args);
+  if (status != 0)
+  {
+    ERROR ("java plugin: cjni_read: AttachCurrentThread failed with status %i.",
+        status);
+    return (-1);
+  }
+
+  cjni_shutdown_plugins (jvm_env);
+
+  (*jvm)->DestroyJavaVM (jvm);
+  jvm = NULL;
+  jvm_env = NULL;
+
+  return (0);
+} /* }}} int cjni_shutdown */
+
+void module_register (void)
+{
+  plugin_register_init ("java", cjni_init);
+  plugin_register_read ("java", cjni_read);
+  plugin_register_shutdown ("java", cjni_shutdown);
+} /* void module_register (void) */
+
+/* vim: set sw=2 sts=2 et fdm=marker : */