[CONF] Apache Qpid: How to Use JNDI (page edited)

confluence Fri, 22 Jun 2007 04:19:21 -0700

Page Edited : qpid : How to Use JNDI

How to Use JNDI has been edited by Martin Ritchie (Jun 22, 2007).

Content:

How to use the PropertiesFileInitialContextFactory

This ContextFactory uses a java properties file to setup initial values.

This is the example properties file.

java.naming.factory.initial = org.apache.qpid.jndi.PropertiesFileInitialContextFactory


# use the following property to configure the default connector
#java.naming.provider.url - ignored.

# register some connection factories
# connectionfactory.[jndiname] = [ConnectionURL]
connectionfactory.local = amqp://guest:[EMAIL PROTECTED]/testpath?brokerlist='vm://:1'

# register some queues in JNDI using the form
# queue.[jndiName] = [physicalName]
queue.MyQueue = example.MyQueue

# register some topics in JNDI using the form
# topic.[jndiName] = [physicalName]
topic.ibmStocks = stocks.nyse.ibm

# Register an AMQP destination in JNDI
#   NOTE: Qpid currently only supports direct,topics and headers
# destination.[jniName] = [BindingURL]
destination.direct = direct://amq.direct//directQueue

The property file allows a number of queues to be defined that can then be discovered via JNDI. There are four properties used by the PFICFactory.
connectionfactory.<jndiname> this is the Connection URL that the connection factory will use to perform connections.
queue.<jndiname> this defines a jms queue or in amqp a amq.direct exchange
topic.<jndiname> this defines a jms topic or in amqp a amq.topic exchange
destination.<jndiname> this takes a Binding URL and so can be used for defining all amq destinations, queues, topics and header matching.

In all of these properties the <jndiname> is the string value that would be given when performing a lookup.

NOTE: This does not create the queue on the broker. You should ensure that you have created the queue before publishing to it. Queues can be declared in the virtualhosts.xml file so that they are created on broker startup, or created dynamically by consuming clients. Topics and other destinations that use temporary queues cannot be created in this way, so a consumer must be created first before publishing messages with mandatory routing.

Example lookup code

The bindingValue is the String that would be placed in <jndiname> above.

Simple JNDI lookup using files

// Load the properties file ... 
Properties properties = new Properties();
properties.load(propertiesfile_inputStream);

// Create the initial context
Context ctx = new InitialContext(properties);

// Perform the binds
object = ctx.lookup(bindingValue);

// Close the context when we're done
ctx.close();

Simple JNDI lookup using properties

final String INITIAL_CONTEXT_FACTORY = "org.apache.qpid.jndi.PropertiesFileInitialContextFactory";

final String CONNECTION_JNDI_NAME = "local";
final String CONNECTION_NAME = "amqp://guest:[EMAIL PROTECTED]/testpath?brokerlist='vm://:1'";

final String QUEUE_JNDI_NAME = "queue";
final String QUEUE_NAME = "example.MyQueue";

// Set the properties ... 
Properties properties = new Properties();
properties.put(Context.INITIAL_CONTEXT_FACTORY, INITIAL_CONTEXT_FACTORY);
properties.put("connectionfactory."+CONNECTION_JNDI_NAME , CONNECTION_NAME);
properties.put("queue."+QUEUE_JNDI_NAME , QUEUE_NAME);

// Create the initial context
Context ctx = new InitialContext(properties);

// Perform the lookups
ConnectionFactory factory = (ConnectionFactory)ctx.lookup(CONNECTION_JNDI_NAME);
Queue queue = (Queue)ctx.lookup(QUEUE_JNDI_NAME);

// Close the context when we're done
ctx.close();

How to use a JNDI Provider

Qpid will work with any JNDI provider capable of storing Java objects. We have a task to add our own initial context factory, but until that's available ....

First you must select a JNDI provider to use. If you aren't already using an application server (i.e. Tomcat ?) which provides JNDI support you could consider using either:

Apache's Directory which provides an LDAP JNDI implementation

OR the SUN JNDI SPI for the FileSystem which can be downloaded from http://java.sun.com/products/jndi/downloads/index.html

Click : Download JNDI 1.2.1 & More button
Download: File System Service Provider, 1.2 Beta 3
and then add the two jars in the lib dir to your class path.

There are two steps to using JNDI objects.

Bind : Which stores a reference to a JMS Object in the provider.
Lookup : Which tries to retrieve the reference and create the JMS Object.

There are two objects that would normally be stored in JNDI.

A ConnectionFactory
A Destination (Queue or Topic)

Binding

Then you need to setup the values that the JNDI provider will used to bind your references, something like this:

Setup JNDI

Hashtable env = new Hashtable(11);
  env.put(Context.INITIAL_CONTEXT_FACTORY,"com.sun.jndi.fscontext.RefFSContextFactory");
  env.put(Context.PROVIDER_URL,LOCAL_FILE_PATH_FOR_STORING_BINDS_PATH_MUST_EXIST);

These values are then used to create a context to bind your references.

Perform Binding of ConnectionFactory

try
{
    Context ctx = new InitialContext(env);

    // Create the object to be bound in this case a ConnectionFactory
    ConnectionFactory factory = null;

    try
    {
        factory = new AMQConnectionFactory(CONNECTION_URL);
        try
        {
            ctx.bind(binding, factory);
        }
        catch (NamingException e)
        {
            //Handle problems with binding. Such as the binding already exists.
        }
    }
    catch (URLSyntaxException amqe)
    {
        //Handle any exception with creating ConnnectionFactory
    }
}
catch (NamingException e)
{
    //Handle problem creating the Context.
}

To bind a queue instead simply create a AMQQueue object and use that in the binding call.

Bind a AMQQueue

AMQQueue  queue = new AMQQueue(QUEUE_URL);
ctx.bind(binding, queue);

Lookup

You can then get a queue connection factory from the JNDI context.

Perform Binding of ConnectionFactory

ConnectionFactory factory;
try
{
    factory= (ConnectionFactory)ctx.lookup(binding);
}
catch (NamingException e)
{
    //Handle problems with lookup. Such as binding does not exist.
}

Note that you need not cast the bound object back to an AMQConnectionFactory so all your current JMS apps that use JNDI can start using Qpid straight away.

How to create a TopicConnectionFactory and QueueConnectionFactory

AMQConnectionFactory implements TopicConnectionFactory and QueueConnectionFactory as well as the ConnectionFactory.

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