001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     * 
010     *      http://www.apache.org/licenses/LICENSE-2.0
011     * 
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.oozie.workflow.lite;
019    
020    
021    import org.apache.oozie.ErrorCode;
022    import org.apache.oozie.util.ParamChecker;
023    import org.apache.oozie.workflow.WorkflowException;
024    
025    import java.util.Arrays;
026    
027    /**
028     * Workflow lite start node definition.
029     */
030    public class StartNodeDef extends ControlNodeDef {
031    
032        /**
033         * Reserved name fo the start node. <p/> It is an invalid token, it will never match an application node name.
034         */
035        public static final String START = ":start:";
036    
037        /**
038         * Default constructor.
039         */
040        public StartNodeDef() {
041        }
042    
043        /**
044         * Create a start node definition.
045         *
046         * @param klass control node handler class.
047         * @param transitionTo transition on workflow start.
048         */
049        public StartNodeDef(Class<? extends ControlNodeHandler> klass, String transitionTo) {
050            super(START, "", klass, Arrays.asList(ParamChecker.notEmpty(transitionTo, "transitionTo")));
051        }
052    
053        /**
054         * Start node handler. <p/> It does an immediate transition to the transitionTo node.
055         */
056        public static class StartNodeHandler extends NodeHandler {
057    
058            public boolean enter(Context context) throws WorkflowException {
059                if (!context.getSignalValue().equals(StartNodeDef.START)) {
060                    throw new WorkflowException(ErrorCode.E0715, context.getSignalValue());
061                }
062                return true;
063            }
064    
065            public String exit(Context context) {
066                return context.getNodeDef().getTransitions().get(0);
067            }
068    
069            public void kill(Context context) {
070            }
071    
072            public void fail(Context context) {
073            }
074        }
075    
076    }