/*
* Copyright 2002-2013 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.orm.jdo.support;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import javax.jdo.PersistenceManager;
import javax.jdo.PersistenceManagerFactory;
import javax.jdo.Query;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.orm.jdo.DefaultJdoDialect;
import org.springframework.orm.jdo.JdoDialect;
import org.springframework.orm.jdo.PersistenceManagerFactoryUtils;
import org.springframework.util.Assert;
/**
* Proxy that implements the {@link javax.jdo.PersistenceManager} interface,
* delegating to the current thread-bound PersistenceManager (the Spring-managed
* transactional PersistenceManager or the single OpenPersistenceManagerInView
* PersistenceManager, if any) on each invocation. This class makes such a
* Spring-style PersistenceManager proxy available for bean references.
*
* <p>The main advantage of this proxy is that it allows DAOs to work with a
* plain JDO PersistenceManager reference in JDO 3.0 style
* (see {@link javax.jdo.PersistenceManagerFactory#getPersistenceManagerProxy()}),
* while still participating in Spring's resource and transaction management.
*
* <p>The behavior of this proxy matches the behavior that the JDO 3.0 spec
* defines for a PersistenceManager proxy. Hence, DAOs could seamlessly switch
* between {@link StandardPersistenceManagerProxyBean} and this Spring-style proxy,
* receiving the reference through Dependency Injection. This will work without
* any Spring API dependencies in the DAO code!
*
* @author Juergen Hoeller
* @since 3.0
* @see StandardPersistenceManagerProxyBean
* @see javax.jdo.PersistenceManagerFactory#getPersistenceManagerProxy()
* @see org.springframework.orm.jdo.PersistenceManagerFactoryUtils#getPersistenceManager
* @see org.springframework.orm.jdo.PersistenceManagerFactoryUtils#releasePersistenceManager
*/
public class SpringPersistenceManagerProxyBean implements FactoryBean<PersistenceManager>, InitializingBean {
private PersistenceManagerFactory persistenceManagerFactory;
private JdoDialect jdoDialect;
private Class<? extends PersistenceManager> persistenceManagerInterface = PersistenceManager.class;
private boolean allowCreate = true;
private PersistenceManager proxy;
/**
* Set the target PersistenceManagerFactory for this proxy.
*/
public void setPersistenceManagerFactory(PersistenceManagerFactory persistenceManagerFactory) {
this.persistenceManagerFactory = persistenceManagerFactory;
}
/**
* Return the target PersistenceManagerFactory for this proxy.
*/
protected PersistenceManagerFactory getPersistenceManagerFactory() {
return this.persistenceManagerFactory;
}
/**
* Set the JDO dialect to use for this proxy.
* <p>Default is a DefaultJdoDialect based on the PersistenceManagerFactory's
* underlying DataSource, if any.
*/
public void setJdoDialect(JdoDialect jdoDialect) {
this.jdoDialect = jdoDialect;
}
/**
* Return the JDO dialect to use for this proxy.
*/
protected JdoDialect getJdoDialect() {
return this.jdoDialect;
}
/**
* Specify the PersistenceManager interface to expose,
* possibly including vendor extensions.
* <p>Default is the standard {@code javax.jdo.PersistenceManager} interface.
*/
public void setPersistenceManagerInterface(Class<? extends PersistenceManager> persistenceManagerInterface) {
this.persistenceManagerInterface = persistenceManagerInterface;
Assert.notNull(persistenceManagerInterface, "persistenceManagerInterface must not be null");
Assert.isAssignable(PersistenceManager.class, persistenceManagerInterface);
}
/**
* Return the PersistenceManager interface to expose.
*/
protected Class<? extends PersistenceManager> getPersistenceManagerInterface() {
return this.persistenceManagerInterface;
}
/**
* Set whether the PersistenceManagerFactory proxy is allowed to create
* a non-transactional PersistenceManager when no transactional
* PersistenceManager can be found for the current thread.
* <p>Default is "true". Can be turned off to enforce access to
* transactional PersistenceManagers, which safely allows for DAOs
* written to get a PersistenceManager without explicit closing
* (i.e. a {@code PersistenceManagerFactory.getPersistenceManager()}
* call without corresponding {@code PersistenceManager.close()} call).
* @see org.springframework.orm.jdo.PersistenceManagerFactoryUtils#getPersistenceManager(javax.jdo.PersistenceManagerFactory, boolean)
*/
public void setAllowCreate(boolean allowCreate) {
this.allowCreate = allowCreate;
}
/**
* Return whether the PersistenceManagerFactory proxy is allowed to create
* a non-transactional PersistenceManager when no transactional
* PersistenceManager can be found for the current thread.
*/
protected boolean isAllowCreate() {
return this.allowCreate;
}
@Override
public void afterPropertiesSet() {
if (getPersistenceManagerFactory() == null) {
throw new IllegalArgumentException("Property 'persistenceManagerFactory' is required");
}
// Build default JdoDialect if none explicitly specified.
if (this.jdoDialect == null) {
this.jdoDialect = new DefaultJdoDialect(getPersistenceManagerFactory().getConnectionFactory());
}
this.proxy = (PersistenceManager) Proxy.newProxyInstance(
getPersistenceManagerFactory().getClass().getClassLoader(),
new Class<?>[] {getPersistenceManagerInterface()}, new PersistenceManagerInvocationHandler());
}
@Override
public PersistenceManager getObject() {
return this.proxy;
}
@Override
public Class<? extends PersistenceManager> getObjectType() {
return getPersistenceManagerInterface();
}
@Override
public boolean isSingleton() {
return true;
}
/**
* Invocation handler that delegates close calls on PersistenceManagers to
* PersistenceManagerFactoryUtils for being aware of thread-bound transactions.
*/
private class PersistenceManagerInvocationHandler implements InvocationHandler {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
// Invocation on PersistenceManager interface coming in...
if (method.getName().equals("equals")) {
// Only consider equal when proxies are identical.
return (proxy == args[0]);
}
else if (method.getName().equals("hashCode")) {
// Use hashCode of PersistenceManager proxy.
return System.identityHashCode(proxy);
}
else if (method.getName().equals("toString")) {
// Deliver toString without touching a target EntityManager.
return "Spring PersistenceManager proxy for target factory [" + getPersistenceManagerFactory() + "]";
}
else if (method.getName().equals("getPersistenceManagerFactory")) {
// Return PersistenceManagerFactory without creating a PersistenceManager.
return getPersistenceManagerFactory();
}
else if (method.getName().equals("isClosed")) {
// Proxy is always usable.
return false;
}
else if (method.getName().equals("close")) {
// Suppress close method.
return null;
}
// Invoke method on target PersistenceManager.
PersistenceManager pm = PersistenceManagerFactoryUtils.doGetPersistenceManager(
getPersistenceManagerFactory(), isAllowCreate());
try {
Object retVal = method.invoke(pm, args);
if (retVal instanceof Query) {
PersistenceManagerFactoryUtils.applyTransactionTimeout(
(Query) retVal, getPersistenceManagerFactory());
}
return retVal;
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
finally {
PersistenceManagerFactoryUtils.doReleasePersistenceManager(pm, getPersistenceManagerFactory());
}
}
}
}