/*
    * 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();
  	}
  	
  }