001/* 002 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved. 003 * 004 * Project and contact information: http://www.cascading.org/ 005 * 006 * This file is part of the Cascading project. 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020 021package cascading.provider; 022 023import cascading.flow.FlowProcess; 024 025/** 026 * Class FactoryLoader is an implementation of a {@link ProviderLoader} and is used to load 027 * {@link CascadingFactory} instances used by internal frameworks. 028 * 029 * @see CascadingFactory 030 */ 031public class FactoryLoader extends ProviderLoader<CascadingFactory> 032 { 033 private static FactoryLoader factoryLoader; 034 035 public synchronized static FactoryLoader getInstance() 036 { 037 if( factoryLoader == null ) 038 factoryLoader = new FactoryLoader(); 039 040 return factoryLoader; 041 } 042 043 public <Factory extends CascadingFactory> Factory loadFactoryFrom( FlowProcess flowProcess, String property, Class<Factory> defaultFactory ) 044 { 045 Object value = flowProcess.getProperty( property ); 046 047 String className; 048 049 if( value == null ) 050 className = defaultFactory.getName(); 051 else 052 className = value.toString(); 053 054 Factory factory = (Factory) createProvider( className ); // todo remove this cast 055 056 if( factory != null ) 057 factory.initialize( flowProcess ); 058 059 return factory; 060 } 061 }