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.action.decision;
016    
017    import org.apache.oozie.client.WorkflowAction;
018    import org.apache.oozie.action.ActionExecutor;
019    import org.apache.oozie.action.ActionExecutorException;
020    import org.apache.oozie.util.XLog;
021    import org.apache.oozie.util.XmlUtils;
022    import org.jdom.Element;
023    import org.jdom.JDOMException;
024    import org.jdom.Namespace;
025    
026    import java.util.List;
027    
028    public class DecisionActionExecutor extends ActionExecutor {
029        public static final String ACTION_TYPE = "switch";
030    
031        private static final String TRUE = "true";
032    
033        public static final String XML_ERROR = "XML_ERROR";
034    
035        public DecisionActionExecutor() {
036            super(ACTION_TYPE);
037        }
038    
039        @SuppressWarnings("unchecked")
040        public void start(Context context, WorkflowAction action) throws ActionExecutorException {
041            XLog log = XLog.getLog(getClass());
042            log.trace("start() begins");
043            try {
044                String confStr = action.getConf();
045                context.setStartData("-", "-", "-");
046                Element conf = XmlUtils.parseXml(confStr);
047                Namespace ns = conf.getNamespace();
048    
049                String externalState = null;
050    
051                for (Element eval : (List<Element>) conf.getChildren("case", ns)) {
052                    if (TRUE.equals(eval.getTextTrim())) {
053                        externalState = eval.getAttributeValue("to");
054                        break;
055                    }
056                }
057                if (externalState == null) {
058                    Element def = conf.getChild("default", ns);
059                    if (def != null) {
060                        externalState = def.getAttributeValue("to");
061                    }
062                }
063    
064                if (externalState == null) {
065                    throw new IllegalStateException("Transition cannot be NULL");
066                }
067                // for decision we are piggybacking on external status to transfer the transition,
068                // the {@link ActionEndCommand} does the special handling of setting it as signal value.
069                context.setExecutionData(externalState, null);
070            }
071            catch (JDOMException ex) {
072                throw new ActionExecutorException(ActionExecutorException.ErrorType.FAILED, XML_ERROR, ex.getMessage(), ex);
073            }
074            finally {
075                log.trace("start() ends");
076            }
077        }
078    
079        public void end(Context context, WorkflowAction action) throws ActionExecutorException {
080            context.setEndData(WorkflowAction.Status.OK, action.getExternalStatus());
081        }
082    
083        public void check(Context context, WorkflowAction action) throws ActionExecutorException {
084            throw new UnsupportedOperationException();
085        }
086    
087        public void kill(Context context, WorkflowAction action) throws ActionExecutorException {
088            throw new UnsupportedOperationException();
089        }
090    
091        public boolean isCompleted(String externalStatus) {
092            return true;
093        }
094    
095    }