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30. JMS (Java Message Service)
Spring provides a JMS integration framework that simplifies the use of the JMS API much like Spring’s integration does for the JDBC API.
JMS can be roughly divided into two areas of functionality, namely the production and consumption of messages. The JmsTemplate
class is used for message production and synchronous message reception. For asynchronous reception similar to Java EE’s message-driven bean style, Spring provides a number of message listener containers that are used to create Message-Driven POJOs (MDPs). Spring also provides a declarative way of creating message listeners.
The package org.springframework.jms.core
provides the core functionality for using JMS. It contains JMS template classes that simplify the use of the JMS by handling the creation and release of resources, much like the JdbcTemplate
does for JDBC. The design principle common to Spring template classes is to provide helper methods to perform common operations and for more sophisticated usage, delegate the essence of the processing task to user implemented callback interfaces. The JMS template follows the same design. The classes offer various convenience methods for the sending of messages, consuming a message synchronously, and exposing the JMS session and message producer to the user.
The package org.springframework.jms.support
provides JMSException
translation functionality. The translation converts the checked JMSException
hierarchy to a mirrored hierarchy of unchecked exceptions. If there are any provider specific subclasses of the checked javax.jms.JMSException
, this exception is wrapped in the unchecked UncategorizedJmsException
.
The package org.springframework.jms.support.converter
provides a MessageConverter
abstraction to convert between Java objects and JMS messages.
The package org.springframework.jms.support.destination
provides various strategies for managing JMS destinations, such as providing a service locator for destinations stored in JNDI.
The package org.springframework.jms.annotation
provides the necessary infrastructure to support annotation-driven listener endpoints using @JmsListener
.
The package org.springframework.jms.config
provides the parser implementation for the jms
namespace as well the java config support to configure listener containers and create listener endpoints.
Finally, the package org.springframework.jms.connection
provides an implementation of the ConnectionFactory
suitable for use in standalone applications. It also contains an implementation of Spring’s PlatformTransactionManager
for JMS (the cunningly named JmsTransactionManager
). This allows for seamless integration of JMS as a transactional resource into Spring’s transaction management mechanisms.
The JmsTemplate
class is the central class in the JMS core package. It simplifies the use of JMS since it handles the creation and release of resources when sending or synchronously receiving messages.
Code that uses the JmsTemplate
only needs to implement callback interfaces giving them a clearly defined high level contract. The MessageCreator
callback interface creates a message given a Session
provided by the calling code in JmsTemplate
. In order to allow for more complex usage of the JMS API, the callback SessionCallback
provides the user with the JMS session and the callback ProducerCallback
exposes a Session
and MessageProducer
pair.
The JMS API exposes two types of send methods, one that takes delivery mode, priority, and time-to-live as Quality of Service (QOS) parameters and one that takes no QOS parameters which uses default values. Since there are many send methods in JmsTemplate
, the setting of the QOS parameters have been exposed as bean properties to avoid duplication in the number of send methods. Similarly, the timeout value for synchronous receive calls is set using the property setReceiveTimeout
.
Some JMS providers allow the setting of default QOS values administratively through the configuration of the ConnectionFactory
. This has the effect that a call to MessageProducer
's send method send(Destination destination, Message message)
will use different QOS default values than those specified in the JMS specification. In order to provide consistent management of QOS values, the JmsTemplate
must therefore be specifically enabled to use its own QOS values by setting the boolean property isExplicitQosEnabled
to true
.
For convenience, JmsTemplate
also exposes a basic request-reply operation that allows to send a message and wait for a reply on a temporary queue that is created as part of the operation.
Note | |
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Instances of the |
As of Spring Framework 4.1, JmsMessagingTemplate
is built on top of JmsTemplate
and provides an integration with the messaging abstraction, i.e. org.springframework.messaging.Message
. This allows you to create the message to send in generic manner.
The JmsTemplate
requires a reference to a ConnectionFactory
. The ConnectionFactory
is part of the JMS specification and serves as the entry point for working with JMS. It is used by the client application as a factory to create connections with the JMS provider and encapsulates various configuration parameters, many of which are vendor specific such as SSL configuration options.
When using JMS inside an EJB, the vendor provides implementations of the JMS interfaces so that they can participate in declarative transaction management and perform pooling of connections and sessions. In order to use this implementation, Java EE containers typically require that you declare a JMS connection factory as a resource-ref
inside the EJB or servlet deployment descriptors. To ensure the use of these features with the JmsTemplate
inside an EJB, the client application should ensure that it references the managed implementation of the ConnectionFactory
.
The standard API involves creating many intermediate objects. To send a message the following 'API' walk is performed
ConnectionFactory->Connection->Session->MessageProducer->send
Between the ConnectionFactory and the Send operation there are three intermediate objects that are created and destroyed. To optimise the resource usage and increase performance two implementations of ConnectionFactory
are provided.
Spring provides an implementation of the ConnectionFactory
interface, SingleConnectionFactory
, that will return the same Connection
on all createConnection()
calls and ignore calls to close()
. This is useful for testing and standalone environments so that the same connection can be used for multiple JmsTemplate
calls that may span any number of transactions. SingleConnectionFactory
takes a reference to a standard ConnectionFactory
that would typically come from JNDI.
The CachingConnectionFactory
extends the functionality of SingleConnectionFactory
and adds the caching of Sessions, MessageProducers, and MessageConsumers. The initial cache size is set to 1, use the property sessionCacheSize
to increase the number of cached sessions. Note that the number of actual cached sessions will be more than that number as sessions are cached based on their acknowledgment mode, so there can be up to 4 cached session instances when sessionCacheSize
is set to one, one for each acknowledgment mode. MessageProducers and MessageConsumers are cached within their owning session and also take into account the unique properties of the producers and consumers when caching. MessageProducers are cached based on their destination. MessageConsumers are cached based on a key composed of the destination, selector, noLocal delivery flag, and the durable subscription name (if creating durable consumers).
Destinations, like ConnectionFactories, are JMS administered objects that can be stored and retrieved in JNDI. When configuring a Spring application context you can use the JNDI factory class JndiObjectFactoryBean
/ <jee:jndi-lookup>
to perform dependency injection on your object’s references to JMS destinations. However, often this strategy is cumbersome if there are a large number of destinations in the application or if there are advanced destination management features unique to the JMS provider. Examples of such advanced destination management would be the creation of dynamic destinations or support for a hierarchical namespace of destinations. The JmsTemplate
delegates the resolution of a destination name to a JMS destination object to an implementation of the interface DestinationResolver
. DynamicDestinationResolver
is the default implementation used by JmsTemplate
and accommodates resolving dynamic destinations. A JndiDestinationResolver
is also provided that acts as a service locator for destinations contained in JNDI and optionally falls back to the behavior contained in DynamicDestinationResolver
.
Quite often the destinations used in a JMS application are only known at runtime and therefore cannot be administratively created when the application is deployed. This is often because there is shared application logic between interacting system components that create destinations at runtime according to a well-known naming convention. Even though the creation of dynamic destinations is not part of the JMS specification, most vendors have provided this functionality. Dynamic destinations are created with a name defined by the user which differentiates them from temporary destinations and are often not registered in JNDI. The API used to create dynamic destinations varies from provider to provider since the properties associated with the destination are vendor specific. However, a simple implementation choice that is sometimes made by vendors is to disregard the warnings in the JMS specification and to use the TopicSession
method createTopic(String topicName)
or the QueueSession
method createQueue(String queueName)
to create a new destination with default destination properties. Depending on the vendor implementation, DynamicDestinationResolver
may then also create a physical destination instead of only resolving one.
The boolean property pubSubDomain
is used to configure the JmsTemplate
with knowledge of what JMS domain is being used. By default the value of this property is false, indicating that the point-to-point domain, Queues, will be used. This property used by JmsTemplate
determines the behavior of dynamic destination resolution via implementations of the DestinationResolver
interface.
You can also configure the JmsTemplate
with a default destination via the property defaultDestination
. The default destination will be used with send and receive operations that do not refer to a specific destination.
One of the most common uses of JMS messages in the EJB world is to drive message-driven beans (MDBs). Spring offers a solution to create message-driven POJOs (MDPs) in a way that does not tie a user to an EJB container. (See Section 30.4.2, “Asynchronous reception: Message-Driven POJOs” for detailed coverage of Spring’s MDP support.) As from Spring Framework 4.1, endpoint methods can be simply annotated using @JmsListener
see Section 30.6, “Annotation-driven listener endpoints” for more details.
A message listener container is used to receive messages from a JMS message queue and drive the MessageListener
that is injected into it. The listener container is responsible for all threading of message reception and dispatches into the listener for processing. A message listener container is the intermediary between an MDP and a messaging provider, and takes care of registering to receive messages, participating in transactions, resource acquisition and release, exception conversion and suchlike. This allows you as an application developer to write the (possibly complex) business logic associated with receiving a message (and possibly responding to it), and delegates boilerplate JMS infrastructure concerns to the framework.
There are two standard JMS message listener containers packaged with Spring, each with its specialised feature set.
This message listener container is the simpler of the two standard flavors. It creates a fixed number of JMS sessions and consumers at startup, registers the listener using the standard JMS MessageConsumer.setMessageListener()
method, and leaves it up the JMS provider to perform listener callbacks. This variant does not allow for dynamic adaption to runtime demands or for participation in externally managed transactions. Compatibility-wise, it stays very close to the spirit of the standalone JMS specification - but is generally not compatible with Java EE’s JMS restrictions.
Note | |
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While The default 'AUTO_ACKNOWLEDGE' mode does not provide proper reliability guarantees. Messages may get lost when listener execution fails (since the provider will automatically acknowledge each message after listener invocation, with no exceptions to be propagated to the provider) or when the listener container shuts down (this may be configured through the 'acceptMessagesWhileStopping' flag). Make sure to use transacted sessions in case of reliability needs, e.g. for reliable queue handling and durable topic subscriptions. |
This message listener container is the one used in most cases. In contrast to SimpleMessageListenerContainer
, this container variant allows for dynamic adaptation to runtime demands and is able to participate in externally managed transactions. Each received message is registered with an XA transaction when configured with a JtaTransactionManager
; so processing may take advantage of XA transaction semantics. This listener container strikes a good balance between low requirements on the JMS provider, advanced functionality such as the participation in externally managed transactions, and compatibility with Java EE environments.
The cache level of the container can be customized. Note that when no caching is enabled, a new connection and a new session is created for each message reception. Combining this with a non durable subscription with high loads may lead to message lost. Make sure to use a proper cache level in such case.
This container also has recoverable capabilities when the broker goes down. By default, a simple BackOff
implementation retries every 5 seconds. It is possible to specify a custom BackOff
implementation for more fine-grained recovery options, see ExponentialBackOff
for an example.
Note | |
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Like its sibling The default 'AUTO_ACKNOWLEDGE' mode does not provide proper reliability guarantees. Messages may get lost when listener execution fails (since the provider will automatically acknowledge each message before listener invocation) or when the listener container shuts down (this may be configured through the 'acceptMessagesWhileStopping' flag). Make sure to use transacted sessions in case of reliability needs, e.g. for reliable queue handling and durable topic subscriptions. |
Spring provides a JmsTransactionManager
that manages transactions for a single JMS ConnectionFactory
. This allows JMS applications to leverage the managed transaction features of Spring as described in Chapter 17, Transaction Management. The JmsTransactionManager
performs local resource transactions, binding a JMS Connection/Session pair from the specified ConnectionFactory
to the thread. JmsTemplate
automatically detects such transactional resources and operates on them accordingly.
In a Java EE environment, the ConnectionFactory
will pool Connections and Sessions, so those resources are efficiently reused across transactions. In a standalone environment, using Spring’s SingleConnectionFactory
will result in a shared JMS Connection
, with each transaction having its own independent Session
. Alternatively, consider the use of a provider-specific pooling adapter such as ActiveMQ’s PooledConnectionFactory
class.
JmsTemplate
can also be used with the JtaTransactionManager
and an XA-capable JMS ConnectionFactory
for performing distributed transactions. Note that this requires the use of a JTA transaction manager as well as a properly XA-configured ConnectionFactory! (Check your Java EE server’s / JMS provider’s documentation.)
Reusing code across a managed and unmanaged transactional environment can be confusing when using the JMS API to create a Session
from a Connection
. This is because the JMS API has only one factory method to create a Session
and it requires values for the transaction and acknowledgment modes. In a managed environment, setting these values is the responsibility of the environment’s transactional infrastructure, so these values are ignored by the vendor’s wrapper to the JMS Connection. When using the JmsTemplate
in an unmanaged environment you can specify these values through the use of the properties sessionTransacted
and sessionAcknowledgeMode
. When using a PlatformTransactionManager
with JmsTemplate
, the template will always be given a transactional JMS Session
.
The JmsTemplate
contains many convenience methods to send a message. There are send methods that specify the destination using a javax.jms.Destination
object and those that specify the destination using a string for use in a JNDI lookup. The send method that takes no destination argument uses the default destination.
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Queue;
import javax.jms.Session;
import org.springframework.jms.core.MessageCreator;
import org.springframework.jms.core.JmsTemplate;
public class JmsQueueSender {
private JmsTemplate jmsTemplate;
private Queue queue;
public void setConnectionFactory(ConnectionFactory cf) {
this.jmsTemplate = new JmsTemplate(cf);
}
public void setQueue(Queue queue) {
this.queue = queue;
}
public void simpleSend() {
this.jmsTemplate.send(this.queue, new MessageCreator() {
public Message createMessage(Session session) throws JMSException {
return session.createTextMessage("hello queue world");
}
});
}
}
This example uses the MessageCreator
callback to create a text message from the supplied Session
object. The JmsTemplate
is constructed by passing a reference to a ConnectionFactory
. As an alternative, a zero argument constructor and connectionFactory
is provided and can be used for constructing the instance in JavaBean style (using a BeanFactory or plain Java code). Alternatively, consider deriving from Spring’s JmsGatewaySupport
convenience base class, which provides pre-built bean properties for JMS configuration.
The method send(String destinationName, MessageCreator creator)
lets you send a message using the string name of the destination. If these names are registered in JNDI, you should set the destinationResolver
property of the template to an instance of JndiDestinationResolver
.
If you created the JmsTemplate
and specified a default destination, the send(MessageCreator c)
sends a message to that destination.
In order to facilitate the sending of domain model objects, the JmsTemplate
has various send methods that take a Java object as an argument for a message’s data content. The overloaded methods convertAndSend()
and receiveAndConvert()
in JmsTemplate
delegate the conversion process to an instance of the MessageConverter
interface. This interface defines a simple contract to convert between Java objects and JMS messages. The default implementation SimpleMessageConverter
supports conversion between String
and TextMessage
, byte[]
and BytesMesssage
, and java.util.Map
and MapMessage
. By using the converter, you and your application code can focus on the business object that is being sent or received via JMS and not be concerned with the details of how it is represented as a JMS message.
The sandbox currently includes a MapMessageConverter
which uses reflection to convert between a JavaBean and a MapMessage
. Other popular implementation choices you might implement yourself are Converters that use an existing XML marshalling package, such as JAXB, Castor, XMLBeans, or XStream, to create a TextMessage
representing the object.
To accommodate the setting of a message’s properties, headers, and body that can not be generically encapsulated inside a converter class, the MessagePostProcessor
interface gives you access to the message after it has been converted, but before it is sent. The example below demonstrates how to modify a message header and a property after a java.util.Map
is converted to a message.
public void sendWithConversion() {
Map map = new HashMap();
map.put("Name", "Mark");
map.put("Age", new Integer(47));
jmsTemplate.convertAndSend("testQueue", map, new MessagePostProcessor() {
public Message postProcessMessage(Message message) throws JMSException {
message.setIntProperty("AccountID", 1234);
message.setJMSCorrelationID("123-00001");
return message;
}
});
}
This results in a message of the form:
MapMessage={
Header={
... standard headers ...
CorrelationID={123-00001}
}
Properties={
AccountID={Integer:1234}
}
Fields={
Name={String:Mark}
Age={Integer:47}
}
}
While the send operations cover many common usage scenarios, there are cases when you want to perform multiple operations on a JMS Session
or MessageProducer
. The SessionCallback
and ProducerCallback
expose the JMS Session
and Session
/ MessageProducer
pair respectively. The execute()
methods on JmsTemplate
execute these callback methods.
While JMS is typically associated with asynchronous processing, it is possible to consume messages synchronously. The overloaded receive(..)
methods provide this functionality. During a synchronous receive, the calling thread blocks until a message becomes available. This can be a dangerous operation since the calling thread can potentially be blocked indefinitely. The property receiveTimeout
specifies how long the receiver should wait before giving up waiting for a message.
Note | |
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Spring also supports annotated-listener endpoints through the use of the |
In a fashion similar to a Message-Driven Bean (MDB) in the EJB world, the Message-Driven POJO (MDP) acts as a receiver for JMS messages. The one restriction (but see also below for the discussion of the MessageListenerAdapter
class) on an MDP is that it must implement the javax.jms.MessageListener
interface. Please also be aware that in the case where your POJO will be receiving messages on multiple threads, it is important to ensure that your implementation is thread-safe.
Below is a simple implementation of an MDP:
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;
public class ExampleListener implements MessageListener {
public void onMessage(Message message) {
if (message instanceof TextMessage) {
try {
System.out.println(((TextMessage) message).getText());
}
catch (JMSException ex) {
throw new RuntimeException(ex);
}
}
else {
throw new IllegalArgumentException("Message must be of type TextMessage");
}
}
}
Once you’ve implemented your MessageListener
, it’s time to create a message listener container.
Find below an example of how to define and configure one of the message listener containers that ships with Spring (in this case the DefaultMessageListenerContainer
).
<!-- this is the Message Driven POJO (MDP) -->
<bean id="messageListener" class="jmsexample.ExampleListener"/>
<!-- and this is the message listener container -->
<bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="connectionFactory" ref="connectionFactory"/>
<property name="destination" ref="destination"/>
<property name="messageListener" ref="messageListener"/>
</bean>
Please refer to the Spring javadocs of the various message listener containers for a full description of the features supported by each implementation.
The SessionAwareMessageListener
interface is a Spring-specific interface that provides a similar contract to the JMS MessageListener
interface, but also provides the message handling method with access to the JMS Session
from which the Message
was received.
package org.springframework.jms.listener;
public interface SessionAwareMessageListener {
void onMessage(Message message, Session session) throws JMSException;
}
You can choose to have your MDPs implement this interface (in preference to the standard JMS MessageListener
interface) if you want your MDPs to be able to respond to any received messages (using the Session
supplied in the onMessage(Message, Session)
method). All of the message listener container implementations that ship with Spring have support for MDPs that implement either the MessageListener
or SessionAwareMessageListener
interface. Classes that implement the SessionAwareMessageListener
come with the caveat that they are then tied to Spring through the interface. The choice of whether or not to use it is left entirely up to you as an application developer or architect.
Please note that the 'onMessage(..)'
method of the SessionAwareMessageListener
interface throws JMSException
. In contrast to the standard JMS MessageListener
interface, when using the SessionAwareMessageListener
interface, it is the responsibility of the client code to handle any exceptions thrown.
The MessageListenerAdapter
class is the final component in Spring’s asynchronous messaging support: in a nutshell, it allows you to expose almost any class as a MDP (there are of course some constraints).
Consider the following interface definition. Notice that although the interface extends neither the MessageListener
nor SessionAwareMessageListener
interfaces, it can still be used as a MDP via the use of the MessageListenerAdapter
class. Notice also how the various message handling methods are strongly typed according to the contents of the various Message
types that they can receive and handle.
public interface MessageDelegate {
void handleMessage(String message);
void handleMessage(Map message);
void handleMessage(byte[] message);
void handleMessage(Serializable message);
}
public class DefaultMessageDelegate implements MessageDelegate {
// implementation elided for clarity...
}
In particular, note how the above implementation of the MessageDelegate
interface (the above DefaultMessageDelegate
class) has no JMS dependencies at all. It truly is a POJO that we will make into an MDP via the following configuration.
<!-- this is the Message Driven POJO (MDP) -->
<bean id="messageListener" class="org.springframework.jms.listener.adapter.MessageListenerAdapter">
<constructor-arg>
<bean class="jmsexample.DefaultMessageDelegate"/>
</constructor-arg>
</bean>
<!-- and this is the message listener container... -->
<bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="connectionFactory" ref="connectionFactory"/>
<property name="destination" ref="destination"/>
<property name="messageListener" ref="messageListener"/>
</bean>
Below is an example of another MDP that can only handle the receiving of JMS TextMessage
messages. Notice how the message handling method is actually called 'receive'
(the name of the message handling method in a MessageListenerAdapter
defaults to 'handleMessage'
), but it is configurable (as you will see below). Notice also how the 'receive(..)'
method is strongly typed to receive and respond only to JMS TextMessage
messages.
public interface TextMessageDelegate {
void receive(TextMessage message);
}
public class DefaultTextMessageDelegate implements TextMessageDelegate {
// implementation elided for clarity...
}
The configuration of the attendant MessageListenerAdapter
would look like this:
<bean id="messageListener" class="org.springframework.jms.listener.adapter.MessageListenerAdapter">
<constructor-arg>
<bean class="jmsexample.DefaultTextMessageDelegate"/>
</constructor-arg>
<property name="defaultListenerMethod" value="receive"/>
<!-- we don't want automatic message context extraction -->
<property name="messageConverter">
<null/>
</property>
</bean>
Please note that if the above 'messageListener'
receives a JMS Message
of a type other than TextMessage
, an IllegalStateException
will be thrown (and subsequently swallowed). Another of the capabilities of the MessageListenerAdapter
class is the ability to automatically send back a response Message
if a handler method returns a non-void value. Consider the interface and class:
public interface ResponsiveTextMessageDelegate {
// notice the return type...
String receive(TextMessage message);
}
public class DefaultResponsiveTextMessageDelegate implements ResponsiveTextMessageDelegate {
// implementation elided for clarity...
}
If the above DefaultResponsiveTextMessageDelegate
is used in conjunction with a MessageListenerAdapter
then any non-null value that is returned from the execution of the 'receive(..)'
method will (in the default configuration) be converted into a TextMessage
. The resulting TextMessage
will then be sent to the Destination
(if one exists) defined in the JMS Reply-To property of the original Message
, or the default Destination
set on the MessageListenerAdapter
(if one has been configured); if no Destination
is found then an InvalidDestinationException
will be thrown (and please note that this exception will not be swallowed and will propagate up the call stack).
Invoking a message listener within a transaction only requires reconfiguration of the listener container.
Local resource transactions can simply be activated through the sessionTransacted
flag on the listener container definition. Each message listener invocation will then operate within an active JMS transaction, with message reception rolled back in case of listener execution failure. Sending a response message (via SessionAwareMessageListener
) will be part of the same local transaction, but any other resource operations (such as database access) will operate independently. This usually requires duplicate message detection in the listener implementation, covering the case where database processing has committed but message processing failed to commit.
<bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="connectionFactory" ref="connectionFactory"/>
<property name="destination" ref="destination"/>
<property name="messageListener" ref="messageListener"/>
<property name="sessionTransacted" value="true"/>
</bean>
For participating in an externally managed transaction, you will need to configure a transaction manager and use a listener container which supports externally managed transactions: typically DefaultMessageListenerContainer
.
To configure a message listener container for XA transaction participation, you’ll want to configure a JtaTransactionManager
(which, by default, delegates to the Java EE server’s transaction subsystem). Note that the underlying JMS ConnectionFactory needs to be XA-capable and properly registered with your JTA transaction coordinator! (Check your Java EE server’s configuration of JNDI resources.) This allows message reception as well as e.g. database access to be part of the same transaction (with unified commit semantics, at the expense of XA transaction log overhead).
<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager"/>
Then you just need to add it to our earlier container configuration. The container will take care of the rest.
<bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="connectionFactory" ref="connectionFactory"/>
<property name="destination" ref="destination"/>
<property name="messageListener" ref="messageListener"/>
<property name="transactionManager" ref="transactionManager"/>
</bean>
Beginning with version 2.5, Spring also provides support for a JCA-based MessageListener
container. The JmsMessageEndpointManager
will attempt to automatically determine the ActivationSpec
class name from the provider’s ResourceAdapter
class name. Therefore, it is typically possible to just provide Spring’s generic JmsActivationSpecConfig
as shown in the following example.
<bean class="org.springframework.jms.listener.endpoint.JmsMessageEndpointManager">
<property name="resourceAdapter" ref="resourceAdapter"/>
<property name="activationSpecConfig">
<bean class="org.springframework.jms.listener.endpoint.JmsActivationSpecConfig">
<property name="destinationName" value="myQueue"/>
</bean>
</property>
<property name="messageListener" ref="myMessageListener"/>
</bean>
Alternatively, you may set up a JmsMessageEndpointManager
with a given ActivationSpec
object. The ActivationSpec
object may also come from a JNDI lookup (using <jee:jndi-lookup>
).
<bean class="org.springframework.jms.listener.endpoint.JmsMessageEndpointManager">
<property name="resourceAdapter" ref="resourceAdapter"/>
<property name="activationSpec">
<bean class="org.apache.activemq.ra.ActiveMQActivationSpec">
<property name="destination" value="myQueue"/>
<property name="destinationType" value="javax.jms.Queue"/>
</bean>
</property>
<property name="messageListener" ref="myMessageListener"/>
</bean>
Using Spring’s ResourceAdapterFactoryBean
, the target ResourceAdapter
may be configured locally as depicted in the following example.
<bean id="resourceAdapter" class="org.springframework.jca.support.ResourceAdapterFactoryBean">
<property name="resourceAdapter">
<bean class="org.apache.activemq.ra.ActiveMQResourceAdapter">
<property name="serverUrl" value="tcp://localhost:61616"/>
</bean>
</property>
<property name="workManager">
<bean class="org.springframework.jca.work.SimpleTaskWorkManager"/>
</property>
</bean>
The specified WorkManager
may also point to an environment-specific thread pool - typically through SimpleTaskWorkManager’s
"asyncTaskExecutor" property. Consider defining a shared thread pool for all your ResourceAdapter
instances if you happen to use multiple adapters.
In some environments (e.g. WebLogic 9 or above), the entire ResourceAdapter
object may be obtained from JNDI instead (using <jee:jndi-lookup>
). The Spring-based message listeners can then interact with the server-hosted ResourceAdapter
, also using the server’s built-in WorkManager
.
Please consult the javadoc for JmsMessageEndpointManager
, JmsActivationSpecConfig
, and ResourceAdapterFactoryBean
for more details.
Spring also provides a generic JCA message endpoint manager which is not tied to JMS: org.springframework.jca.endpoint.GenericMessageEndpointManager
. This component allows for using any message listener type (e.g. a CCI MessageListener) and any provider-specific ActivationSpec object. Check out your JCA provider’s documentation to find out about the actual capabilities of your connector, and consult GenericMessageEndpointManager
's javadoc for the Spring-specific configuration details.
Note | |
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JCA-based message endpoint management is very analogous to EJB 2.1 Message-Driven Beans; it uses the same underlying resource provider contract. Like with EJB 2.1 MDBs, any message listener interface supported by your JCA provider can be used in the Spring context as well. Spring nevertheless provides explicit 'convenience' support for JMS, simply because JMS is the most common endpoint API used with the JCA endpoint management contract. |
The easiest way to receive a message asynchronously is to use the annotated listener endpoint infrastructure. In a nutshell, it allows you to expose a method of a managed bean as a JMS listener endpoint.
@Component
public class MyService {
@JmsListener(destination = "myDestination")
public void processOrder(String data) { ... }
}
The idea of the example above is that whenever a message is available on the javax.jms.Destination
"myDestination", the processOrder
method is invoked accordingly (in this case, with the content of the JMS message similarly to what the MessageListenerAdapter
provides).
The annotated endpoint infrastructure creates a message listener container behind the scenes for each annotated method, using a JmsListenerContainerFactory
. Such a container is not registered against the application context but can be easily located for management purposes using the JmsListenerEndpointRegistry
bean.
Tip | |
---|---|
|
To enable support for @JmsListener
annotations add @EnableJms
to one of your @Configuration
classes.
@Configuration
@EnableJms
public class AppConfig {
@Bean
public DefaultJmsListenerContainerFactory jmsListenerContainerFactory() {
DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
factory.setConnectionFactory(connectionFactory());
factory.setDestinationResolver(destinationResolver());
factory.setSessionTransacted(true);
factory.setConcurrency("3-10");
return factory;
}
}
By default, the infrastructure looks for a bean named jmsListenerContainerFactory
as the source for the factory to use to create message listener containers. In this case, and ignoring the JMS infrastructure setup, the processOrder
method can be invoked with a core poll size of 3 threads and a maximum pool size of 10 threads.
It is possible to customize the listener container factory to use per annotation or an explicit default can be configured by implementing the JmsListenerConfigurer
interface. The default is only required if at least one endpoint is registered without a specific container factory. See the javadoc for full details and examples.
If you prefer XML configuration use the <jms:annotation-driven>
element.
<jms:annotation-driven/>
<bean id="jmsListenerContainerFactory"
class="org.springframework.jms.config.DefaultJmsListenerContainerFactory">
<property name="connectionFactory" ref="connectionFactory"/>
<property name="destinationResolver" ref="destinationResolver"/>
<property name="sessionTransacted" value="true"/>
<property name="concurrency" value="3-10"/>
</bean>
JmsListenerEndpoint
provides a model of an JMS endpoint and is responsible for configuring the container for that model. The infrastructure allows you to configure endpoints programmatically in addition to the ones that are detected by the JmsListener
annotation.
@Configuration
@EnableJms
public class AppConfig implements JmsListenerConfigurer {
@Override
public void configureJmsListeners(JmsListenerEndpointRegistrar registrar) {
SimpleJmsListenerEndpoint endpoint = new SimpleJmsListenerEndpoint();
endpoint.setId("myJmsEndpoint");
endpoint.setDestination("anotherQueue");
endpoint.setMessageListener(message -> {
// processing
});
registrar.registerEndpoint(endpoint);
}
}
In the example above, we used SimpleJmsListenerEndpoint
which provides the actual MessageListener
to invoke but you could just as well build your own endpoint variant describing a custom invocation mechanism.
It should be noted that you could just as well skip the use of @JmsListener
altogether and only register your endpoints programmatically through JmsListenerConfigurer
.
So far, we have been injecting a simple String
in our endpoint but it can actually have a very flexible method signature. Let’s rewrite it to inject the Order
with a custom header:
@Component
public class MyService {
@JmsListener(destination = "myDestination")
public void processOrder(Order order, @Header("order_type") String orderType) {
...
}
}
These are the main elements you can inject in JMS listener endpoints:
- The raw
javax.jms.Message
or any of its subclasses (provided of course that it matches the incoming message type). - The
javax.jms.Session
for optional access to the native JMS API e.g. for sending a custom reply. - The
org.springframework.messaging.Message
representing the incoming JMS message. Note that this message holds both the custom and the standard headers (as defined byJmsHeaders
). @Header
-annotated method arguments to extract a specific header value, including standard JMS headers.@Headers
-annotated argument that must also be assignable tojava.util.Map
for getting access to all headers.- A non-annotated element that is not one of the supported types (i.e.
Message
andSession
) is considered to be the payload. You can make that explicit by annotating the parameter with@Payload
. You can also turn on validation by adding an extra@Valid
.
The ability to inject Spring’s Message
abstraction is particularly useful to benefit from all the information stored in the transport-specific message without relying on transport-specific API.
@JmsListener(destination = "myDestination")
public void processOrder(Message<Order> order) { ... }
Handling of method arguments is provided by DefaultMessageHandlerMethodFactory
which can be further customized to support additional method arguments. The conversion and validation support can be customized there as well.
For instance, if we want to make sure our Order
is valid before processing it, we can annotate the payload with @Valid
and configure the necessary validator as follows:
@Configuration
@EnableJms
public class AppConfig implements JmsListenerConfigurer {
@Override
public void configureJmsListeners(JmsListenerEndpointRegistrar registrar) {
registrar.setMessageHandlerMethodFactory(myJmsHandlerMethodFactory());
}
@Bean
public DefaultMessageHandlerMethodFactory myHandlerMethodFactory() {
DefaultMessageHandlerMethodFactory factory = new DefaultMessageHandlerMethodFactory();
factory.setValidator(myValidator());
return factory;
}
}
The existing support in MessageListenerAdapter already allows your method to have a non-void
return type. When that’s the case, the result of the invocation is encapsulated in a javax.jms.Message
sent either in the destination specified in the JMSReplyTo
header of the original message or in the default destination configured on the listener. That default destination can now be set using the @SendTo
annotation of the messaging abstraction.
Assuming our processOrder
method should now return an OrderStatus
, it is possible to write it as follow to automatically send a response:
@JmsListener(destination = "myDestination")
@SendTo("status")
public OrderStatus processOrder(Order order) {
// order processing
return status;
}
Tip | |
---|---|
If you have several |
If you need to set additional headers in a transport-independent manner, you could return a Message
instead, something like:
@JmsListener(destination = "myDestination")
@SendTo("status")
public Message<OrderStatus> processOrder(Order order) {
// order processing
return MessageBuilder
.withPayload(status)
.setHeader("code", 1234)
.build();
}
If you need to compute the response destination at runtime, you can encapsulate your response in a JmsResponse
instance that also provides the destination to use at runtime. The previous example can be rewritten as follows:
@JmsListener(destination = "myDestination")
public JmsResponse<Message<OrderStatus>> processOrder(Order order) {
// order processing
Message<OrderStatus> response = MessageBuilder
.withPayload(status)
.setHeader("code", 1234)
.build();
return JmsResponse.forQueue(response, "status");
}
Spring provides an XML namespace for simplifying JMS configuration. To use the JMS namespace elements you will need to reference the JMS schema:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jms="http://www.springframework.org/schema/jms"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/jms http://www.springframework.org/schema/jms/spring-jms.xsd">
<!-- bean definitions here -->
</beans>
The namespace consists of three top-level elements: <annotation-driven/>
, <listener-container/>
and <jca-listener-container/>
. <annotation-driven
enables the use of annotation-driven listener endpoints. <listener-container/>
and <jca-listener-container/>
defines shared listener container configuration and may contain <listener/>
child elements. Here is an example of a basic configuration for two listeners.
<jms:listener-container>
<jms:listener destination="queue.orders" ref="orderService" method="placeOrder"/>
<jms:listener destination="queue.confirmations" ref="confirmationLogger" method="log"/>
</jms:listener-container>
The example above is equivalent to creating two distinct listener container bean definitions and two distinct MessageListenerAdapter
bean definitions as demonstrated in Section 30.4.4, “MessageListenerAdapter”. In addition to the attributes shown above, the listener
element may contain several optional ones. The following table describes all available attributes:
Table 30.1. Attributes of the JMS <listener> element
Attribute | Description |
---|---|
id |
A bean name for the hosting listener container. If not specified, a bean name will be automatically generated. |
destination (required) |
The destination name for this listener, resolved through the |
ref (required) |
The bean name of the handler object. |
method |
The name of the handler method to invoke. If the |
response-destination |
The name of the default response destination to send response messages to. This will be applied in case of a request message that does not carry a "JMSReplyTo" field. The type of this destination will be determined by the listener-container’s "response-destination-type" attribute. Note: This only applies to a listener method with a return value, for which each result object will be converted into a response message. |
subscription |
The name of the durable subscription, if any. |
selector |
An optional message selector for this listener. |
concurrency |
The number of concurrent sessions/consumers to start for this listener. Can either be a simple number indicating the maximum number (e.g. "5") or a range indicating the lower as well as the upper limit (e.g. "3-5"). Note that a specified minimum is just a hint and might be ignored at runtime. Default is the value provided by the container |
The <listener-container/>
element also accepts several optional attributes. This allows for customization of the various strategies (for example, taskExecutor
and destinationResolver
) as well as basic JMS settings and resource references. Using these attributes, it is possible to define highly-customized listener containers while still benefiting from the convenience of the namespace.
Such settings can be automatically exposed as a JmsListenerContainerFactory
by specifying the id of the bean to expose through the factory-id
attribute.
<jms:listener-container connection-factory="myConnectionFactory"
task-executor="myTaskExecutor"
destination-resolver="myDestinationResolver"
transaction-manager="myTransactionManager"
concurrency="10">
<jms:listener destination="queue.orders" ref="orderService" method="placeOrder"/>
<jms:listener destination="queue.confirmations" ref="confirmationLogger" method="log"/>
</jms:listener-container>
The following table describes all available attributes. Consult the class-level javadocs of the AbstractMessageListenerContainer
and its concrete subclasses for more details on the individual properties. The javadocs also provide a discussion of transaction choices and message redelivery scenarios.
Table 30.2. Attributes of the JMS <listener-container> element
Attribute | Description |
---|---|
container-type |
The type of this listener container. Available options are: |
container-class |
A custom listener container implementation class as fully qualified class name. Default is Spring’s standard |
factory-id |
Exposes the settings defined by this element as a |
connection-factory |
A reference to the JMS |
task-executor |
A reference to the Spring |
destination-resolver |
A reference to the |
message-converter |
A reference to the |
error-handler |
A reference to an |
destination-type |
The JMS destination type for this listener: |
response-destination-type |
The JMS destination type for responses: "queue", "topic". Default is the value of the "destination-type" attribute. |
client-id |
The JMS client id for this listener container. Needs to be specified when using durable subscriptions. |
cache |
The cache level for JMS resources: |
acknowledge |
The native JMS acknowledge mode: |
transaction-manager |
A reference to an external |
concurrency |
The number of concurrent sessions/consumers to start for each listener. Can either be a simple number indicating the maximum number (e.g. "5") or a range indicating the lower as well as the upper limit (e.g. "3-5"). Note that a specified minimum is just a hint and might be ignored at runtime. Default is 1; keep concurrency limited to 1 in case of a topic listener or if queue ordering is important; consider raising it for general queues. |
prefetch |
The maximum number of messages to load into a single session. Note that raising this number might lead to starvation of concurrent consumers! |
receive-timeout |
The timeout to use for receive calls (in milliseconds). The default is |
back-off |
Specify the |
recovery-interval |
Specify the interval between recovery attempts, in milliseconds. Convenience way to create a |
phase |
The lifecycle phase within which this container should start and stop. The lower the value the earlier this container will start and the later it will stop. The default is |
Configuring a JCA-based listener container with the "jms" schema support is very similar.
<jms:jca-listener-container resource-adapter="myResourceAdapter"
destination-resolver="myDestinationResolver"
transaction-manager="myTransactionManager"
concurrency="10">
<jms:listener destination="queue.orders" ref="myMessageListener"/>
</jms:jca-listener-container>
The available configuration options for the JCA variant are described in the following table:
Table 30.3. Attributes of the JMS <jca-listener-container/> element
Attribute | Description |
---|---|
factory-id |
Exposes the settings defined by this element as a |
resource-adapter |
A reference to the JCA |
activation-spec-factory |
A reference to the |
destination-resolver |
A reference to the |
message-converter |
A reference to the |
destination-type |
The JMS destination type for this listener: |
response-destination-type |
The JMS destination type for responses: "queue", "topic". Default is the value of the "destination-type" attribute. |
client-id |
The JMS client id for this listener container. Needs to be specified when using durable subscriptions. |
acknowledge |
The native JMS acknowledge mode: |
transaction-manager |
A reference to a Spring |
concurrency |
The number of concurrent sessions/consumers to start for each listener. Can either be a simple number indicating the maximum number (e.g. "5") or a range indicating the lower as well as the upper limit (e.g. "3-5"). Note that a specified minimum is just a hint and will typically be ignored at runtime when using a JCA listener container. Default is 1. |
prefetch |
The maximum number of messages to load into a single session. Note that raising this number might lead to starvation of concurrent consumers! |