/*
    * Copyright 2006-2011 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.impl.resourceloader;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.core.api.config.property.ConfigContext;
  import org.kuali.rice.core.api.reflect.ObjectDefinition;
  import org.kuali.rice.core.api.resourceloader.ServiceLocator;
  import org.kuali.rice.core.api.util.ClassLoaderUtils;
  import org.kuali.rice.core.api.util.RiceConstants;
  import org.kuali.rice.core.framework.resourceloader.BaseResourceLoader;
  
  import javax.xml.namespace.QName;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * A BaseResourceLoader implementation which wraps services with a Proxy that
   * switches the current context ClassLoader of the Thread.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class BaseWrappingResourceLoader extends BaseResourceLoader {
  
  	private static final String[] PACKAGES_TO_FILTER = new String[] { "org.springframework" };
  	private Set<QName> servicesToCache = new HashSet<QName>();
  	private Map<QName, Object> serviceCache = Collections.synchronizedMap(new HashMap<QName, Object>());
  
  	public BaseWrappingResourceLoader(QName name, ClassLoader classLoader, ServiceLocator serviceLocator) {
  		super(name, classLoader, serviceLocator);
  	}
  
  	public BaseWrappingResourceLoader(QName name, ClassLoader classLoader) {
  		super(name, classLoader);
  	}
  
  	public BaseWrappingResourceLoader(QName name, ServiceLocator serviceLocator) {
  		super(name, serviceLocator);
  	}
  
  	public BaseWrappingResourceLoader(QName name) {
  		super(name);
  	}
  
  
  
  	@Override
  	public void start() throws Exception {
  	    String servicesToCacheFromConfig = ConfigContext.getCurrentContextConfig().getProperty(RiceConstants.SERVICES_TO_CACHE);
  	    if (!StringUtils.isEmpty(servicesToCacheFromConfig)) {
  		String[] services = servicesToCacheFromConfig.split(",");
  		for (String serviceName : services) {
  		    serviceName = serviceName.trim();
  		    try {
  			servicesToCache.add(QName.valueOf(serviceName));
  			LOG.info("Adding service " + serviceName + " to service cache.");
  		    } catch (IllegalArgumentException e) {
  			LOG.error("Failed to parse serviceName into QName from property " + RiceConstants.SERVICES_TO_CACHE +".  Service name given was: " + serviceName);
  		    }
  		}
  	    }
  	    super.start();
  	}
  
  	@Override
  	public Object getService(QName serviceName) {
  	    Object service = serviceCache.get(serviceName);
  	    if (service != null) {
  		if (LOG.isDebugEnabled()) {
  		    LOG.debug("Service with QName " + serviceName + " was retrieved from the service cache.");
  		}
  		return service;
  	    }
  	    return super.getService(serviceName);
  	}
  
  	protected Object postProcessService(QName serviceName, Object service) {
  		if (service != null && shouldWrapService(serviceName, service)) {
  			service = ContextClassLoaderProxy.wrap(service, ClassLoaderUtils.getInterfacesToProxy(service, getClassLoader(), getPackageNamesToFilter()), getClassLoader());
  		}
  		cacheService(serviceName, service);
  		return service;
 	}
 
 	protected Object postProcessObject(ObjectDefinition definition, Object object) {
 		if (object != null && shouldWrapObject(definition, object)) {
 			return ContextClassLoaderProxy.wrap(object, ClassLoaderUtils.getInterfacesToProxy(object, getClassLoader(), getPackageNamesToFilter()), getClassLoader(), getClassLoader());
 		}
 		return object;
 	}
 
 	protected void cacheService(QName serviceName, Object service) {
 	    if (shouldCacheService(serviceName, service)) {
 		LOG.debug("Adding service " + serviceName + " to the service cache.");
 		serviceCache.put(serviceName, service);
 	    }
 	}
 
 	protected String[] getPackageNamesToFilter() {
 		return PACKAGES_TO_FILTER;
 	}
 
 	protected boolean shouldWrapService(QName serviceName, Object service) {
 		return true;
 	}
 
 	protected boolean shouldCacheService(QName serviceName, Object service) {
 	    return servicesToCache.contains(serviceName);
 	}
 
 	protected boolean shouldWrapObject(ObjectDefinition definition, Object object) {
 		return true;
 	}
 
 }