001 /** 002 * Copyright (c) 2010 Yahoo! Inc. All rights reserved. 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. See accompanying LICENSE file. 014 */ 015 package org.apache.oozie.workflow.lite; 016 017 018 import org.apache.oozie.workflow.WorkflowException; 019 import org.apache.oozie.util.ParamChecker; 020 import org.apache.oozie.ErrorCode; 021 022 import java.util.ArrayList; 023 import java.util.List; 024 025 /** 026 * Workflow lite start node definition. 027 */ 028 public class StartNodeDef extends NodeDef { 029 030 /** 031 * Reserved name fo the start node. <p/> It is an invalid token, it will never match an application node name. 032 */ 033 public static final String START = "::start::"; 034 035 /** 036 * Default constructor. 037 */ 038 public StartNodeDef() { 039 } 040 041 /** 042 * Create a start node definition. 043 * 044 * @param transitionTo transition on workflow start. 045 */ 046 public StartNodeDef(String transitionTo) { 047 super(START, null, StartNodeHandler.class, createList(ParamChecker.notEmpty(transitionTo, "transitionTo"))); 048 } 049 050 private static List<String> createList(String transition) { 051 List<String> list = new ArrayList<String>(); 052 list.add(transition); 053 return list; 054 } 055 056 /** 057 * Start node handler. <p/> It does an immediate transition to the transitionTo node. 058 */ 059 public static class StartNodeHandler extends NodeHandler { 060 061 public boolean enter(Context context) throws WorkflowException { 062 if (!context.getSignalValue().equals(StartNodeDef.START)) { 063 throw new WorkflowException(ErrorCode.E0715, context.getSignalValue()); 064 } 065 return true; 066 } 067 068 public String exit(Context context) { 069 return context.getNodeDef().getTransitions().get(0); 070 } 071 072 public void kill(Context context) { 073 } 074 075 public void fail(Context context) { 076 } 077 } 078 079 }