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You can use GCJ to build ActiveMQ as a shared library you can reuse from C++. Native compile ActiveMQ HOWTOAbstractThis document describes how to native compile ActiveMQ for use in a C++ environment. The version of ActiveMQ used is 3.2 in this howto. To compile you'll need GCC 4.0.2, or later, with both Java, and C/C++ support. Tools SetupIf you don't already have GCC 4.0.2 installed you need to download and build it. See GCC manuals for complete instructions on how to build GCC but below is a short descriptions of the steps involved. The GCC build steps assumes that you already have an older GCC compiler installed.
Write the Glue CodeEither access the ActiveMQ classes directly from C++ or write a facade object in Java that handles all startup and shutdown logic of ActiveMQ. Save the glue files in the same directory as for the ActiveMQ jars. An CNI example using a Java object starting the MQ. Bootstrap.cpp#include <gcj/cni.h>
#include <iostream>
#include <java/lang/System.h>
#include <java/lang/Throwable.h>
#include <java/io/PrintStream.h>
#include "MQAdapter.h"
using namespace std;
int main(int argc, char* argv[])
{
cout << "Entering main" << endl;
using namespace java::lang;
try
{
// Create and startup Java VM
JvCreateJavaVM(NULL) ;
JvAttachCurrentThread(NULL, NULL) ;
System::out->println(JvNewStringLatin1("Java println")) ;
// Start ActiveMQ
MQAdapter* pAdapter = new MQAdapter() ;
pAdapter->start() ;
// Send a message
pAdapter->send(JvNewStringLatin1("Hello World!")) ;
// Shutdown ActiveMQ
pAdapter->stop() ;
JvDetachCurrentThread() ;
}
catch( Throwable *t )
{
System::err->println(JvNewStringLatin1("Exception")) ;
t->printStackTrace() ;
}
}
MQAdapter.javaimport org.activemq.*;
import java.util.Hashtable ;
import javax.jms.*;
import javax.naming.*;
public class MQAdapter
{
private InitialContext jndiContext ;
private QueueConnectionFactory factory ;
private QueueConnection connection ;
private QueueSession session ;
private QueueSender sender ;
private Queue queue ;
public MQAdapter()
{
}
public void start()
{
try
{
Hashtable props = new Hashtable() ;
props.put(Context.INITIAL_CONTEXT_FACTORY, "org.activemq.jndi.ActiveMQInitialContextFactory") ;
props.put(Context.PROVIDER_URL, "tcp://localhost:61616") ;
props.put("queue.MyQueue", "example.MyQueue") ;
jndiContext = new InitialContext(props) ;
// Create and configure JMS connection factory
factory = (QueueConnectionFactory)jndiContext.lookup("ConnectionFactory") ;
// Lookup Queue
queue = (Queue)jndiContext.lookup("MyQueue") ;
// Create a JMS connection
connection = (QueueConnection)factory.createQueueConnection() ;
System.out.println("Created connection: " + connection) ;
// Create a JMS session
session = connection.createQueueSession(false, Session.AUTO_ACKNOWLEDGE) ;
System.out.println("Created session: " + session) ;
// Create JMS sender
sender = session.createSender(queue) ;
}
catch( Exception e )
{
e.printStackTrace() ;
try
{
if( connection != null )
connection.close() ;
} catch( JMSException jmse )
{ /* ignore */ }
}
}
public void stop()
{
try
{
if( connection != null )
connection.close() ;
} catch( JMSException e )
{ /* ignore */ }
}
public void send(String msg)
{
TextMessage message ;
try
{
message = session.createTextMessage(msg) ;
sender.send(message) ;
}
catch( JMSException e )
{
e.printStackTrace() ;
}
}
}
Compile the Java and C++ CodeThe Java code must be BC compiled to be able to dynamically link required classes as needed, see reference for more information on BC compilation. Use the suggested script to compile all ActiveMQ JARs and create a class map database. Note Using -Bsymbolic does not seem to work, use -symbolic instead. compile.sh:
#!/bin/sh
# Create new classmap database
gcj-dbtool -n classmap.db
for JAR_FILE in `find -iname "*.jar"`
do
echo "Compiling ${JAR_FILE} to native"
gcj -shared -findirect-dispatch -fjni -fPIC -Wl,-symbolic -o ${JAR_FILE}.so ${JAR_FILE}
gcj-dbtool -a classmap.db ${JAR_FILE} ${JAR_FILE}.so
done
Now, if everything went ok you should be able to run the app. with ./Bootstrap. References |