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19.6. Configuring WS-RM Persistence
The Apache CXF WS-RM features already described in this chapter provide reliability for cases such as network failures. WS-RM persistence provides reliability across other types of failure such as an RM source or an RM destination crash.
WS-RM persistence involves storing the state of the various RM endpoints in persistent storage. This enables the endpoints to continue sending and receiving messages when they are reincarnated.
Apache CXF enables WS-RM persistence in a configuration file. The default WS-RM persistence store is JDBC-based. For convenience, Apache CXF includes Derby for out-of-the-box deployment. In addition, the persistent store is also exposed using a Java API. To implement your own persistence mechanism, you can implement one using this API with your preferred DB.
WS-RM persistence is supported for oneway calls only, and it is disabled by default.
How it works
Apache CXF WS-RM persistence works as follows:
- At the RM source endpoint, an outgoing message is persisted before transmission. It is evicted from the persistent store after the acknowledgement is received.
- After a recovery from crash, it recovers the persisted messages and retransmits until all the messages have been acknowledged. At that point, the RM sequence is closed.
- At the RM destination endpoint, an incoming message is persisted, and upon a successful store, the acknowledgement is sent. When a message is successfully dispatched, it is evicted from the persistent store.
- After a recovery from a crash, it recovers the persisted messages and dispatches them. It also brings the RM sequence to a state where new messages are accepted, acknowledged, and delivered.
To enable WS-RM persistence, you must specify the object implementing the persistent store for WS-RM. You can develop your own or you can use the JDBC based store that comes with Apache CXF.
The configuration shown in Example 19.14, “Configuration for the Default WS-RM Persistence Store” enables the JDBC-based store that comes with Apache CXF.
Example 19.14. Configuration for the Default WS-RM Persistence Store
<bean id="RMTxStore" class="org.apache.cxf.ws.rm.persistence.jdbc.RMTxStore"/> <wsrm-mgr:rmManager id="org.apache.cxf.ws.rm.RMManager"> <property name="store" ref="RMTxStore"/> </wsrm-mgr:rmManager>
The JDBC-based store that comes with Apache CXF supports the properties shown in Table 19.4, “JDBC Store Properties”.
Table 19.4. JDBC Store Properties
The configuration shown in Example 19.15, “Configuring the JDBC Store for WS-RM Persistence” enables the JDBC-based store that comes with Apache CXF, while setting the driverClassName and url to non-default values.
Example 19.15. Configuring the JDBC Store for WS-RM Persistence
<bean id="RMTxStore" class="org.apache.cxf.ws.rm.persistence.jdbc.RMTxStore"> <property name="driverClassName" value="com.acme.jdbc.Driver"/> <property name="url" value="jdbc:acme:rmdb;create=true"/> </bean>