=============================================================================== jalam

Production grade J2SE JMS client.

Features :

• Failover : Automatic reconnection.
• Cascading failover between servers if available.
• Parallel connections to multiple servers
• Parallel subscription to multiple topics/queues
• Includes default listeners : STDOUT, journaling
• Extensible : Implements custom listener, or more complex interface, to setup/release additionnal resources. (I/O, network, connection pools)

Building from sources :

git clone https://github.com/sfr-network-service-platforms/jalam.git
mvn dependency:copy-dependencies package install

Binary release is available under ${basedir}/target/jalam-.jar Required runtime libraries are available under ${basedir}/target/dependency

The JAR archive classpath requires the following deployment layout :

./jalam-<version>.jar
./lib/<runtime-libraries>.jar

Configuration :

Upon startup, a list of configured JNDI providers is loaded from a classpath file named 'jms.properties'. It allows to define :

• Logical groups of servers
• Servers that belongs to those groups.

Simple setup :

The simplest configuration file contains the following :

# A default group
config.groups=default

# A JNDI provider whose alias is 'broker00'
default.jms.server.broker00.host=broker00.mydomain.com
default.jms.server.broker00.port=7676

Active/active setup, with failover :

By defining multiple logical groups, it's possible to create an active/active message consumer :

• At runtime, a subscription will be established to one server in each group.
• This allows to balance load between server, for ex. in a cluster.

Defining multiple servers in a group allows for failover capabilities, when/if the active server becomes unavailable.

config.groups=datacenter1,datacenter2

datacenter1.jms.server.server1.host=server1.datacenter1.organization.com
datacenter1.jms.server.server1.port=7676
datacenter1.jms.server.server2.host=server2.datacenter1.organization.com
datacenter1.jms.server.server2.port=7676

datacenter2.jms.server.server1.host=server1.datacenter2.organization.com
datacenter2.jms.server.server1.port=7676
datacenter2.jms.server.server2.host=server2.datacenter2.organization.com
datacenter2.jms.server.server2.port=7676

Listener/Destination Setup :

To use a listener other than the default, the names of the listener classes and their destinations must be specified in the jms.properties file. Multiple listeners and multiple destinations are specified in comma separated strings:

# Class names of listeners
config.listeners=net.sfr.tv.listener.TopicListener1,net.sfr.tv.listener.TopicListener2,net.sfr.tv.listener.TopicListener3
# Destinations
net.sfr.tv.listener.TopicListener1.destinations=/topic/1
net.sfr.tv.listener.TopicListener2.destinations=/topic/1,/topic/2
net.sfr.tv.listener.TopicListener3.destinations=/topic/3

Usage :

java -cp jalam-<version>.jar net.sfr.tv.jms.client.Bootstrap <arguments>

Available arguments are :

(-Dconfig.path=your.configPath) (-Dhandler.class=your.lifeCycleController) -jar jalam.jar -d [destination] (-c [clientId]) -s [subscriptionName] (-q) (-p) (-cf[connectionFactoryName]) <-f [filter]>

• -q : Destination is a queue. Topic is default.
• -p : Create a persistent ('durable') subscription. Default is false.
• -u : Unsubscribe an active durable subscription, then exit.
• -cf : JNDI Connection Factory name. Default 'ConsumerConnectionFactory'.
• -Dconfig.path : Set the path of the configuration files. Instead, they should be in the binary directory.
• -Dhandler.class : Set the LifeCycleController to use. Default is net.sfr.tv.jms.client.DefaultLifeCycleController. If a MessageListener is passed, then the DefaultLifeCycleController use a dedicated one instead of net.sfr.tv.jms.client.listener.LoggerMessageListener

Examples :

Persistent topic subscription, with clientID set :

java -jar jalam.jar -d /topic/1 -p -s mySubscriptionIdentifier -c myClientId

Unsubscribe then exit :

java -jar jalam.jar -u -s mySubscriptionIdentifier -c myClientId

Subscribe to multiple destinations :

java -jar jalam.jar -d /topic/1,/topic/2,/topic/3 -s mySubscriptionIdentifier

Default Listeners :

By default, Jalam uses a 'Logger Listener' which output messages content to Log4J.

• A custom logger can be used, by setting the system property 'listener.class' (-Dlistener.class=your.listener)
• Output can be restricted to only include message body, by setting the system property 'listener.output.type' to 'BODY'

An alternative default listener which outputs to a file is provided :

• The FileOutMessageListener is provided in the jalam package
• -Dlistener.class=net.sfr.tv.jms.client.listener.FileOutMessageListener
• Destination file is set with the system property 'listener.file.output'. (must be an absolute path)
• -Dlistener.file.output=/home/username/tmp/jalam.log

Refer to the next section to use customs MessageListeners.

Extensibility :

Message listeners :

To use a custom MessageListener with Jalam, you have to implement the interface net.sfr.tv.jms.client.api.MessageListenerWrapper. It provides a release() method, which is called upon program termination, and allows to release any specific resource.

Lifecycle provider :

In order to handle more complex usage, where you need to initialize and keep tracks of many resources outside of the JMS listeners, you can implement the net.sfr.tv.jms.client.api.LifecycleControllerInterface, which provides the following methods :

• run() : Called at startup, and allows to initialize resource such as thread pools, external network connections (JDBC,FTP, etc...)
• release() : Release previously mentionned resources.
• getListener()