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JdoInterceptor (Spring Framework) - Spring Framework 1.2.9 API 文档英文版

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org.springframework.orm.jdo
Class JdoInterceptor

java.lang.Object
  org.springframework.orm.jdo.JdoAccessor
      org.springframework.orm.jdo.JdoInterceptor

All Implemented Interfaces:

Advice, Interceptor, MethodInterceptor, InitializingBean

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public class JdoInterceptor
extends JdoAccessor
implements MethodInterceptor

This interceptor binds a new JDO PersistenceManager to the thread before a method call, closing and removing it afterwards in case of any method outcome. If there already is a pre-bound PersistenceManager (e.g. from JdoTransactionManager, or from a surrounding JDO-intercepted method), the interceptor simply participates in it.

Application code must retrieve a JDO PersistenceManager via the PersistenceManagerFactoryUtils.getPersistenceManager method, to be able to detect a thread-bound PersistenceManager. It is preferable to use getPersistenceManager with allowCreate=false, if the code relies on the interceptor to provide proper PersistenceManager handling. Typically, the code will look as follows:

 public void doJdoAction() {
   PersistenceManager pm = PersistenceManagerFactoryUtils.getPersistenceManager(this.pmf, false);
   try {
     ...
   }
   catch (JDOException ex) {
     throw PersistenceManagerFactoryUtils.convertJdoAccessException(ex);
   }
 }

Note that the application must care about handling JDOExceptions itself, preferably via delegating to the PersistenceManagerFactoryUtils.convertJdoAccessException method that converts them to exceptions that are compatible with the org.springframework.dao exception hierarchy (like JdoTemplate does).

This interceptor could convert unchecked JDOExceptions to unchecked dao ones on-the-fly. The intercepted method wouldn't have to throw any special checked exceptions to be able to achieve this. Nevertheless, such a mechanism would effectively break the contract of the intercepted method (runtime exceptions can be considered part of the contract too), therefore it isn't supported.

This class can be considered a declarative alternative to JdoTemplate's callback approach. The advantages are:

• no anonymous classes necessary for callback implementations;
• the possibility to throw any application exceptions from within data access code.

The drawbacks are:

• the dependency on interceptor configuration;
• the delegating try/catch blocks.

Since:

13.06.2003

Author:

Juergen Hoeller

See Also:

PersistenceManagerFactoryUtils.getPersistenceManager(javax.jdo.PersistenceManagerFactory, boolean), JdoTransactionManager, JdoTemplate

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Field Summary

 

Fields inherited from class org.springframework.orm.jdo.JdoAccessor
logger

 

Constructor Summary
JdoInterceptor()

 

Method Summary
Object	invoke(MethodInvocation methodInvocation)

 

Methods inherited from class org.springframework.orm.jdo.JdoAccessor
afterPropertiesSet, convertJdoAccessException, flushIfNecessary, getJdoDialect, getPersistenceManagerFactory, isFlushEager, setFlushEager, setJdoDialect, setPersistenceManagerFactory

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

JdoInterceptor

public JdoInterceptor()

Method Detail

invoke

public Object invoke(MethodInvocation methodInvocation)
              throws Throwable

Specified by:

invoke in interface MethodInterceptor

Throws:

Throwable

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