/*
* $Id: FactorySet.java 471754 2006-11-06 14:55:09Z husted $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.struts.tiles.xmlDefinition;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import org.apache.struts.tiles.ComponentDefinition;
import org.apache.struts.tiles.ComponentDefinitionsFactory;
import org.apache.struts.tiles.DefinitionsFactoryException;
import org.apache.struts.tiles.FactoryNotFoundException;
import org.apache.struts.tiles.NoSuchDefinitionException;
/**
* Component Definitions factory.
* This factory contains several factories identified by a key. The
* getDefinition() method first looks for the factory key, retrieves or creates this
* factory and then calls its getDefinition().
*/
public abstract class FactorySet implements ComponentDefinitionsFactory
{
/** Loaded factories */
protected Map factories=null;
/**
* Extract key that will be used to get the sub factory.
* @param name Name of requested definition.
* @param request Current servlet request.
* @param servletContext Current servlet context.
* @return Object.
*/
abstract protected Object getDefinitionsFactoryKey(String name, ServletRequest request, ServletContext servletContext);
/**
* Get default factory.
* @return Default factory.
*/
abstract protected DefinitionsFactory getDefaultFactory();
/**
* Get a factory by its key.
* If key is <code>null</code>, return defaultFactory.
* Search in loaded factories. If not found, create factory and store return value in
* loaded factories.
* @param key Key of requested definition.
* @param request Current servlet request.
* @param servletContext Current servlet context.
* @throws DefinitionsFactoryException If an error occur while creating factory.
*/
protected DefinitionsFactory getFactory(Object key, ServletRequest request, ServletContext servletContext)
throws DefinitionsFactoryException
{
if(key == null )
return getDefaultFactory();
Object factory = factories.get( key );
if( factory == null )
{
// synchronize creation to avoid double creation by separate threads.
// Also, check if factory hasn't been created while waiting for synchronized
// section.
synchronized(factories)
{
factory = factories.get( key );
if( factory == null )
{
factory = createFactory( key, request, servletContext);
factories.put( key, factory );
} // end if
} // end synchronized
} // end if
return (DefinitionsFactory)factory;
}
/**
* Get a definition by its name.
*
* @param name Name of requested definition.
* @param request Current servlet request.
* @param servletContext Current servlet context.
* @throws NoSuchDefinitionException No definition found for specified name
* @throws DefinitionsFactoryException General exception
*/
public ComponentDefinition getDefinition(String name, ServletRequest request, ServletContext servletContext)
throws NoSuchDefinitionException, DefinitionsFactoryException
{
if( factories == null )
throw new FactoryNotFoundException( "No definitions factory defined" );
Object key = getDefinitionsFactoryKey( name, request, servletContext);
DefinitionsFactory factory = getFactory( key, request, servletContext);
return factory.getDefinition( name, request, servletContext );
}
/**
* Create a factory for specified key.
* This method is called by getFactory() when the requested factory doesn't already exist.
* Must return a factory, or a default one.
* Real implementation needs to provide this method.
* @param key Key of requested definition.
* @param request Current servlet request.
* @param servletContext Current servlet context
* @throws DefinitionsFactoryException If an error occur while creating factory.
*/
abstract protected DefinitionsFactory createFactory(Object key, ServletRequest request, ServletContext servletContext)
throws DefinitionsFactoryException;
/**
* Init factory set.
* @param servletContext Current servlet context
* @param properties properties used to initialized factory set;
*/
abstract public void initFactory(ServletContext servletContext, Map properties)
throws DefinitionsFactoryException;
/**
* Constructor.
*/
public FactorySet()
{
factories = new HashMap();
}
/**
* Return String representation.
* @return String representation.
*/
public String toString()
{
Iterator i = factories.values().iterator();
StringBuffer buff = new StringBuffer( "all FactorySet's factory : \n" );
while( i.hasNext() )
{
buff.append( i.next().toString() ).append("\n");
}
return buff.toString();
}
}