/*

  * Copyright 2007-2008 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.core.ojb;

 import java.util.Collection;

 import org.apache.ojb.broker.PBKey;

 import org.apache.ojb.broker.PersistenceBrokerException;

 import org.apache.ojb.broker.core.proxy.CollectionProxyDefaultImpl;

 import org.apache.ojb.broker.query.Query;

 import org.kuali.rice.core.util.ClassLoaderUtils;

 import org.kuali.rice.core.util.ContextClassLoaderBinder;

 /**

  * Sets up the context classloader properly for OJB proxies.  The sequence of events in the super class is as

  * follows:

  * 

  * <pre>

  * public synchronized Collection getData()

  * {

  *    if (!isLoaded())

  *    {

  *      beforeLoading();

  *      setData(loadData());

  *      afterLoading();

  *    }

  *    return _data;

  * }

  * </pre>

  *

  * Therefore, since there is no try-catch-finally in conjunction with this call, we need to handle exceptions thrown

  * from loadData and unbind the classloader appropriately.

  */

 public class ContextClassLoaderCollectionProxy extends CollectionProxyDefaultImpl {

         private static final long serialVersionUID = 6425238292133556808L;

         // this object is used by object that's are serialized and we don't want to take this reference

         // across the wire.  May need to acquire the CCL if this is null on beforeLoading() doing nothing for now...

         private transient ClassLoader contextClassLoader;

         public ContextClassLoaderCollectionProxy(PBKey aKey, Class aCollClass, Query aQuery) {

                 super(aKey, aCollClass, aQuery);

                 this.contextClassLoader = ClassLoaderUtils.getDefaultClassLoader();

         }

         public ContextClassLoaderCollectionProxy(PBKey aKey, Query aQuery) {

                 super(aKey, aQuery);

                 this.contextClassLoader = ClassLoaderUtils.getDefaultClassLoader();        

         }

         @Override

         protected void beforeLoading() {

                 ContextClassLoaderBinder.bind(this.contextClassLoader);

                 super.beforeLoading();

         }

         @Override

         protected Collection loadData() throws PersistenceBrokerException {

                 try {

                         return super.loadData();

                 } catch (Throwable t) {

                         ContextClassLoaderBinder.unbind();

                         if (t instanceof PersistenceBrokerException) {

                                 throw (PersistenceBrokerException)t;

                         } else if (t instanceof Error) {

                                 throw (Error)t;

                         } else if (t instanceof RuntimeException) {

                                 throw (RuntimeException)t;

                         } else {

                                 throw new PersistenceBrokerException("Invalid exception type thrown!", t);

                         }

                 }

         }

         @Override

         protected void afterLoading() {

                 super.afterLoading();

                 ContextClassLoaderBinder.unbind();

         }

 }