Java binding beautified, inline documentation added

AUTHORS

@@ -13,6 +13,7 @@ Erich Heine
 Erik Rigtorp
 Frank Denis
 George Neill
+Gonzalo Diethelm
 Joe Thornber
 Jon Dyte
 Kamil Shakirov

bindings/java/Context.cpp

@@ -17,8 +17,6 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <stdlib.h>
-#include <string.h>
 #include <assert.h>
 #include <errno.h>
 
@@ -26,9 +24,51 @@
 
 #include "org_zmq_Context.h"
 
+/** Handle to Java's Context::contextHandle. */
 static jfieldID ctx_handle_fid = NULL;
 
-static void raise_exception (JNIEnv *env, int err)
+/**
+ * Make sure we have a valid pointer to Java's Context::contextHandle.
+ */
+static void ensure_context (JNIEnv *env,
+			    jobject obj)
+{
+    if (ctx_handle_fid == NULL) {
+        jclass cls = env->GetObjectClass (obj);
+	assert (cls);
+	ctx_handle_fid = env->GetFieldID (cls, "contextHandle", "J");
+	assert (ctx_handle_fid);
+	env->DeleteLocalRef (cls);
+    }
+}
+
+/**
+ * Get the value of Java's Context::contextHandle.
+ */
+static void *get_context (JNIEnv *env,
+			  jobject obj)
+{
+    ensure_context (env, obj);
+    void *s = (void*) env->GetLongField (obj, ctx_handle_fid);
+    return s;
+}
+
+/**
+ * Set the value of Java's Context::contextHandle.
+ */
+static void put_context (JNIEnv *env,
+			 jobject obj,
+			 void *s)
+{
+    ensure_context (env, obj);
+    env->SetLongField (obj, ctx_handle_fid, (jlong) s);
+}
+
+/**
+ * Raise an exception that includes 0MQ's error message.
+ */
+static void raise_exception (JNIEnv *env,
+			     int err)
 {
     //  Get exception class.
     jclass exception_class = env->FindClass ("java/lang/Exception");
@@ -39,52 +79,42 @@ static void raise_exception (JNIEnv *env, int err)
 
     //  Raise the exception.
     int rc = env->ThrowNew (exception_class, err_msg);
-    assert (rc == 0);
-
-    //  Free the local ref.
     env->DeleteLocalRef (exception_class);
+
+    assert (rc == 0);
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Context_construct (JNIEnv *env, jobject obj,
-    jint app_threads, jint io_threads, jint flags)
+/**
+ * Called to construct a Java Context object.
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Context_construct (JNIEnv *env,
+						       jobject obj,
+						       jint app_threads,
+						       jint io_threads,
+						       jint flags)
 {
-    if (ctx_handle_fid == NULL) {
-        jclass cls = env->GetObjectClass (obj);
-        assert (cls);
-        ctx_handle_fid = env->GetFieldID (cls, "contextHandle", "J");
-        assert (ctx_handle_fid);
-        env->DeleteLocalRef (cls);
-    }
+    void *c = get_context (env, obj);
+    assert (! c);
+
+    c = zmq_init (app_threads, io_threads, flags);
+    put_context(env, obj, c);
 
-    void *ctx = zmq_init (app_threads, io_threads, flags);
-    if (ctx == NULL) {
+    if (c == NULL) {
         raise_exception (env, errno);
         return;
     }
-
-    env->SetLongField (obj, ctx_handle_fid, (jlong) ctx);
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Context_finalize (JNIEnv *env, jobject obj)
+/**
+ * Called to destroy a Java Context object.
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Context_finalize (JNIEnv *env,
+						      jobject obj)
 {
-    void *ctx = (void*) env->GetLongField (obj, ctx_handle_fid);
-    assert (ctx);
+    void *c = get_context (env, obj);
+    assert (c);
 
-    int rc = zmq_term (ctx);
+    int rc = zmq_term (c);
+    put_context (env, obj, NULL);
     assert (rc == 0);
 }
-
-JNIEXPORT jlong JNICALL Java_org_zmq_Context_createSocket (JNIEnv *env,
-    jobject obj, jint type)
-{
-    void *ctx = (void*) env->GetLongField (obj, ctx_handle_fid);
-    assert (ctx);
-
-    void *s = zmq_socket (ctx, type);
-    if (s == NULL) {
-        raise_exception (env, errno);
-        return -1;
-    }
-
-    return (jlong) s;
-}

bindings/java/Socket.cpp

@@ -17,7 +17,6 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 #include <errno.h>
@@ -27,9 +26,79 @@
 
 #include "org_zmq_Socket.h"
 
+/** Handle to Java's Socket::socketHandle. */
 static jfieldID socket_handle_fid = NULL;
-static jmethodID create_socket_mid = NULL;
 
+/**
+ * Make sure we have a valid pointer to Java's Socket::socketHandle.
+ */
+static void ensure_socket (JNIEnv *env,
+			   jobject obj)
+{
+    if (socket_handle_fid == NULL) {
+        jclass cls = env->GetObjectClass (obj);
+	assert (cls);
+	socket_handle_fid = env->GetFieldID (cls, "socketHandle", "J");
+	assert (socket_handle_fid);
+	env->DeleteLocalRef (cls);
+    }
+}
+
+/**
+ * Get the value of Java's Socket::socketHandle.
+ */
+static void *get_socket (JNIEnv *env,
+			 jobject obj)
+{
+    ensure_socket (env, obj);
+    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    return s;
+}
+
+/**
+ * Set the value of Java's Socket::socketHandle.
+ */
+static void put_socket (JNIEnv *env,
+			jobject obj,
+			void *s)
+{
+    ensure_socket (env, obj);
+    env->SetLongField (obj, socket_handle_fid, (jlong) s);
+}
+
+/**
+ * Get the value of contextHandle for the Java Context associated with
+ * this Java Socket object.
+ */
+static void *fetch_context (JNIEnv *env,
+			    jobject context)
+{
+    static jmethodID get_context_handle_mid = NULL;
+
+    if (get_context_handle_mid == NULL) {
+        jclass cls = env->GetObjectClass (context);
+	assert (cls);
+
+	get_context_handle_mid = env->GetMethodID (cls,
+						   "getContextHandle",
+						   "()J");
+	env->DeleteLocalRef (cls);
+	assert (get_context_handle_mid);
+    }
+
+    void *zmq_ctx = (void*) env->CallLongMethod (context,
+						 get_context_handle_mid);
+    if (env->ExceptionCheck ()) {
+        zmq_ctx = NULL;
+    }
+
+    assert (zmq_ctx);
+    return zmq_ctx;
+}
+
+/**
+ * Raise an exception that includes 0MQ's error message.
+ */
 static void raise_exception (JNIEnv *env, int err)
 {
     //  Get exception class.
@@ -41,46 +110,49 @@ static void raise_exception (JNIEnv *env, int err)
 
     //  Raise the exception.
     int rc = env->ThrowNew (exception_class, err_msg);
-    assert (rc == 0);
-
-    //  Free the local ref.
     env->DeleteLocalRef (exception_class);
+
+    assert (rc == 0);
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Socket_construct (JNIEnv *env, jobject obj,
-    jobject context, jint type)
+/**
+ * Called to construct a Java Socket object.
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Socket_construct (JNIEnv *env,
+						      jobject obj,
+						      jobject context,
+						      jint type)
 {
-    if (socket_handle_fid == NULL) {
-        jclass cls = env->GetObjectClass (obj);
-        assert (cls);
-        socket_handle_fid = env->GetFieldID (cls, "socketHandle", "J");
-        assert (socket_handle_fid);
-        env->DeleteLocalRef (cls);
-    }
+    void *s = get_socket (env, obj);
+    assert (! s);
 
-    if (create_socket_mid == NULL) {
-        jclass cls = env->FindClass ("org/zmq/Context");
-        assert (cls);
-        create_socket_mid = env->GetMethodID (cls, "createSocket", "(I)J");
-        assert (create_socket_mid);
-        env->DeleteLocalRef (cls);
-    }
-
-    void *s = (void*) env->CallLongMethod (context, create_socket_mid, type);
-    if (env->ExceptionCheck ())
-        return;
+    void *zmq_ctx = fetch_context (env, context);
+    s = zmq_socket (zmq_ctx, type);
+    put_socket(env, obj, s);
 
-    env->SetLongField (obj, socket_handle_fid, (jlong) s);
+    if (s == NULL) {
+        raise_exception (env, errno);
+	return;
+    }
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Socket_finalize (JNIEnv *env, jobject obj)
+/**
+ * Called to destroy a Java Socket object.
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Socket_finalize (JNIEnv *env,
+						     jobject obj)
 {
-    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    void *s = get_socket (env, obj);
     assert (s);
+
     int rc = zmq_close (s);
+    put_socket (env, obj, NULL);
     assert (rc == 0);
 }
 
+/**
+ * Called by Java's Socket::setsockopt(int option, long optval).
+ */
 JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__IJ (JNIEnv *env,
     jobject obj, jint option, jlong optval)
 {
@@ -93,7 +165,7 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__IJ (JNIEnv *env,
     case ZMQ_RECOVERY_IVL:
     case ZMQ_MCAST_LOOP:
         {
-            void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+            void *s = get_socket (env, obj);
             assert (s);
 
             int64_t value = optval;
@@ -108,8 +180,14 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__IJ (JNIEnv *env,
     }
 }
 
+/**
+ * Called by Java's Socket::setsockopt(int option, String optval).
+ */
 JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__ILjava_lang_String_2 (
-    JNIEnv *env, jobject obj, jint option, jstring optval)
+    JNIEnv *env,
+    jobject obj,
+    jint option,
+    jstring optval)
 {
     switch (option) {
     case ZMQ_IDENTITY:
@@ -121,8 +199,8 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__ILjava_lang_String_2 (
                 return;
             }
 
-            void *s = (void*) env->GetLongField (obj, socket_handle_fid);
-            assert (s);
+	    void *s = get_socket (env, obj);
+	    assert (s);
 
             const char *value = env->GetStringUTFChars (optval, NULL);
             assert (value);
@@ -138,10 +216,14 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_setsockopt__ILjava_lang_String_2 (
     }
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Socket_bind (JNIEnv *env, jobject obj,
-    jstring addr)
+/**
+ * Called by Java's Socket::bind(String addr).
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Socket_bind (JNIEnv *env,
+						 jobject obj,
+						 jstring addr)
 {
-    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    void *s = get_socket (env, obj);
     assert (s);
 
     if (addr == NULL) {
@@ -162,10 +244,14 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_bind (JNIEnv *env, jobject obj,
         raise_exception (env, errno);
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Socket_connect (JNIEnv *env, jobject obj,
-    jstring addr)
+/**
+ * Called by Java's Socket::connect(String addr).
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Socket_connect (JNIEnv *env,
+						    jobject obj,
+						    jstring addr)
 {
-    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    void *s = get_socket (env, obj);
     assert (s);
 
     if (addr == NULL) {
@@ -186,10 +272,15 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_connect (JNIEnv *env, jobject obj,
         raise_exception (env, errno);
 }
 
-JNIEXPORT jboolean JNICALL Java_org_zmq_Socket_send (JNIEnv *env, jobject obj,
-    jbyteArray msg, jlong flags)
+/**
+ * Called by Java's Socket::send(byte [] msg, long flags).
+ */
+JNIEXPORT jboolean JNICALL Java_org_zmq_Socket_send (JNIEnv *env,
+						     jobject obj,
+						     jbyteArray msg,
+						     jlong flags)
 {
-    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    void *s = get_socket (env, obj);
     assert (s);
 
     jsize size = env->GetArrayLength (msg); 
@@ -222,9 +313,13 @@ JNIEXPORT jboolean JNICALL Java_org_zmq_Socket_send (JNIEnv *env, jobject obj,
     return JNI_TRUE;
 }
 
-JNIEXPORT void JNICALL Java_org_zmq_Socket_flush (JNIEnv *env, jobject obj)
+/**
+ * Called by Java's Socket::flush().
+ */
+JNIEXPORT void JNICALL Java_org_zmq_Socket_flush (JNIEnv *env,
+						  jobject obj)
 {
-    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    void *s = get_socket (env, obj);
     assert (s);
 
     int rc = zmq_flush (s);
@@ -235,10 +330,14 @@ JNIEXPORT void JNICALL Java_org_zmq_Socket_flush (JNIEnv *env, jobject obj)
     }
 }
 
-JNIEXPORT jbyteArray JNICALL Java_org_zmq_Socket_recv (JNIEnv *env, jobject obj,
-    jlong flags)
+/**
+ * Called by Java's Socket::recv(long flags).
+ */
+JNIEXPORT jbyteArray JNICALL Java_org_zmq_Socket_recv (JNIEnv *env,
+						       jobject obj,
+						       jlong flags)
 {
-    void *s = (void*) env->GetLongField (obj, socket_handle_fid);
+    void *s = get_socket (env, obj);
     assert (s);
 
     zmq_msg_t message;
@@ -258,8 +357,10 @@ JNIEXPORT jbyteArray JNICALL Java_org_zmq_Socket_recv (JNIEnv *env, jobject obj,
 
     jbyteArray data = env->NewByteArray (zmq_msg_size (&message));
     assert (data);
-    env->SetByteArrayRegion (data, 0, zmq_msg_size (&message),
-        (jbyte*) zmq_msg_data (&message));
+    env->SetByteArrayRegion (data,
+			     0,
+			     zmq_msg_size (&message),
+			     (jbyte*) zmq_msg_data (&message));
 
     return data;
 }

bindings/java/org/zmq/Context.java

@@ -36,17 +36,22 @@ public class Context {
         construct (appThreads, ioThreads, flags);
     }
 
-    /**
-     * Internal function. Do not use directly!
-     */
-    public native long createSocket (int type);
-
     /** Initialize the JNI interface */
     protected native void construct (int appThreads, int ioThreads, int flags);
 
-    /** Free resources used by JNI driver. */
+    /** Free all resources used by JNI interface. */
     protected native void finalize ();
 
+    /**
+     * Get the underlying context handle.
+     *
+     * @return the internal 0MQ context handle.
+     */
+    private long getContextHandle () {
+	return contextHandle;
+    }
+
+
     /** Opaque data used by JNI driver. */
     private long contextHandle;
 }

bindings/java/org/zmq/Socket.java

-        /*
+/*
     Copyright (c) 2007-2010 iMatix Corporation
 
     This file is part of 0MQ.
@@ -19,9 +19,7 @@
 
 package org.zmq;
 
-public class Socket
-{
-
+public class Socket {
     static {
         System.loadLibrary("jzmq");
     }
@@ -52,44 +50,53 @@ public class Socket
     public static final int SNDBUF = 11;
     public static final int RCVBUF = 12;
 
+
     /**
      * Class constructor.
      *
-     * @param context
-     * @param type
+     * @param context a 0MQ context previously created.
+     * @param type the socket type.
      */
     public Socket (Context context, int type) {
         construct (context, type);
     }
 
     /**
-     * Set the socket option value.
+     * Set the socket option value, given as a long.
+     *
+     * @param option ID of the option to set.
+     * @param optval value (as a long) to set the option to.
+     */
+    public native void setsockopt (int option, long optval);
+
+    /**
+     * Set the socket option value, given as a String.
      *
-     * @param option ID of the option to set
-     * @param optval value to set the option to
+     * @param option ID of the option to set.
+     * @param optval value (as a String) to set the option to.
      */
-     public native void setsockopt (int option, long optval);
-     public native void setsockopt (int option, String optval);
+    public native void setsockopt (int option, String optval);
 
     /**
      * Bind to network interface. Start listening for new connections.
      *
-     * @param addr
+     * @param addr the endpoint to bind to.
      */
     public native void bind (String addr);
 
     /**
      * Connect to remote application.
      *
-     * @param addr
+     * @param addr the endpoint to connect to.
      */
     public native void connect (String addr);
 
     /**
-     * Send the message.
+     * Send a message.
      *
-     * @param msg
-     * @param flags
+     * @param msg the message to send, as an array of bytes.
+     * @param flags the flags to apply to the send operation.
+     * @return true if send was successful, false otherwise.
      */
     public native boolean send (byte [] msg, long flags);
 
@@ -99,19 +106,29 @@ public class Socket
     public native void flush ();
 
     /**
-     * Receive message.
+     * Receive a message.
      *
-     * @param flags
-     * @return
+     * @param flags the flags to apply to the receive operation.
+     * @return the message received, as an array of bytes; null on error.
      */
     public native byte [] recv (long flags);
 
-    /** Initialize JNI driver */
+    /** Initialize the JNI interface */
     protected native void construct (Context context, int type);
 
-    /** Free all resources used by JNI driver. */
+    /** Free all resources used by JNI interface. */
     protected native void finalize ();
 
+    /**
+     * Get the underlying socket handle.
+     *
+     * @return the internal 0MQ socket handle.
+     */
+    private long getSocketHandle () {
+	return socketHandle;
+    }
+
+
     /** Opaque data used by JNI driver. */
     private long socketHandle;