001// Copyright 2005 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.hivemind.lib.chain; 016 017import java.util.ArrayList; 018import java.util.Iterator; 019import java.util.List; 020 021import org.apache.hivemind.ServiceImplementationFactory; 022import org.apache.hivemind.ServiceImplementationFactoryParameters; 023import org.apache.hivemind.order.Orderer; 024 025/** 026 * Builds a service implementation using {@link org.apache.hivemind.lib.chain.ChainBuilder}. 027 * 028 * @author Howard M. Lewis Ship 029 * @since 1.1 030 */ 031public class ChainFactory implements ServiceImplementationFactory 032{ 033 private ChainBuilder _chainBuilder; 034 035 public Object createCoreServiceImplementation( 036 ServiceImplementationFactoryParameters factoryParameters) 037 { 038 List contributions = (List) factoryParameters.getFirstParameter(); 039 040 Orderer orderer = new Orderer(factoryParameters.getErrorLog(), "command"); 041 042 Iterator i = contributions.iterator(); 043 while (i.hasNext()) 044 { 045 ChainContribution cc = (ChainContribution) i.next(); 046 orderer.add(cc, cc.getId(), cc.getAfter(), cc.getBefore()); 047 } 048 049 List ordered = orderer.getOrderedObjects(); 050 051 List commands = new ArrayList(ordered.size()); 052 053 i = ordered.iterator(); 054 while (i.hasNext()) 055 { 056 ChainContribution cc = (ChainContribution) i.next(); 057 058 // TODO: Validate that command for each ChainContribution implements the 059 // service interface. 060 061 commands.add(cc.getCommand()); 062 } 063 064 String toString = "<ChainImplementation for " + factoryParameters.getServiceId() + "(" 065 + factoryParameters.getServiceInterface().getName() + ")>"; 066 067 return _chainBuilder.buildImplementation( 068 factoryParameters.getServiceInterface(), 069 commands, 070 toString); 071 } 072 073 public void setChainBuilder(ChainBuilder chainBuilder) 074 { 075 _chainBuilder = chainBuilder; 076 } 077}