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    import org.apache.oozie.ErrorCode;
021    import org.apache.oozie.workflow.WorkflowException;
022    
023    import java.util.ArrayList;
024    import java.util.List;
025    
026    
027    /**
028     * Node handler that provides the necessary workflow logic for control nodes: START/END/KILL/FORK/JOIN.
029     */
030    public abstract class ControlNodeHandler extends NodeHandler {
031    
032        public static final String FORK_COUNT_PREFIX = "workflow.fork.";
033    
034        /**
035         * Called by {@link #enter(Context)} when returning TRUE.
036         *
037         * @param context workflow context
038         * @throws WorkflowException thrown if an error occurred.
039         */
040        public abstract void touch(Context context) throws WorkflowException;
041    
042        @Override
043        public boolean enter(Context context) throws WorkflowException {
044            boolean doTouch;
045            Class<? extends NodeDef> nodeClass = context.getNodeDef().getClass();
046            if (nodeClass.equals(StartNodeDef.class)) {
047                if (!context.getSignalValue().equals(StartNodeDef.START)) {
048                    throw new WorkflowException(ErrorCode.E0715, context.getSignalValue());
049                }
050                doTouch = true;
051            }
052            else if (nodeClass.equals(EndNodeDef.class)) {
053                doTouch = true;
054            }
055            else if (nodeClass.equals(KillNodeDef.class)) {
056                doTouch = true;
057            }
058            else if (nodeClass.equals(ForkNodeDef.class)) {
059                doTouch = true;
060            }
061            else if (nodeClass.equals(JoinNodeDef.class)) {
062                String parentExecutionPath = context.getParentExecutionPath(context.getExecutionPath());
063                String forkCount = context.getVar(FORK_COUNT_PREFIX + parentExecutionPath);
064                if (forkCount == null) {
065                    throw new WorkflowException(ErrorCode.E0720, context.getNodeDef().getName());
066                }
067                int count = Integer.parseInt(forkCount) - 1;
068                if (count > 0) {
069                    context.setVar(FORK_COUNT_PREFIX + parentExecutionPath, "" + count);
070                    context.deleteExecutionPath();
071                }
072                else {
073                    context.setVar(FORK_COUNT_PREFIX + parentExecutionPath, null);
074                }
075                doTouch = (count == 0);
076            }
077            else {
078                throw new IllegalStateException("Invalid node type: " + nodeClass);
079            }
080            if (doTouch) {
081                touch(context);
082            }
083            return false;
084        }
085    
086        @Override
087        public String exit(Context context) throws WorkflowException {
088            Class<? extends NodeDef> nodeClass = context.getNodeDef().getClass();
089            if (nodeClass.equals(StartNodeDef.class)) {
090                return context.getNodeDef().getTransitions().get(0);
091            }
092            else if (nodeClass.equals(EndNodeDef.class)) {
093                context.completeJob();
094                return null;
095            }
096            else if (nodeClass.equals(KillNodeDef.class)) {
097                context.killJob();
098                return null;
099            }
100            else if (nodeClass.equals(ForkNodeDef.class)) {
101                throw new UnsupportedOperationException();
102            }
103            else if (nodeClass.equals(JoinNodeDef.class)) {
104                throw new UnsupportedOperationException();
105            }
106            else {
107                throw new IllegalStateException("Invalid node type: " + nodeClass);
108            }
109        }
110    
111        @Override
112        public void loopDetection(Context context)
113            throws WorkflowException {
114            Class<? extends NodeDef> nodeClass = context.getNodeDef().getClass();
115            if (nodeClass.equals(StartNodeDef.class)) {
116            }
117            else if (nodeClass.equals(EndNodeDef.class)) {
118            }
119            else if (nodeClass.equals(KillNodeDef.class)) {
120            }
121            else if (nodeClass.equals(ForkNodeDef.class)) {
122            }
123            else if (nodeClass.equals(JoinNodeDef.class)) {
124                String flag = getLoopFlag(context.getNodeDef().getName());
125                if (context.getVar(flag) != null) {
126                    throw new WorkflowException(ErrorCode.E0709, context.getNodeDef().getName());
127                }
128                String parentExecutionPath = context.getParentExecutionPath(context.getExecutionPath());
129                String forkCount = context.getVar(FORK_COUNT_PREFIX + parentExecutionPath);
130                if (forkCount == null) {
131                    throw new WorkflowException(ErrorCode.E0720, context.getNodeDef().getName());
132                }
133                int count = Integer.parseInt(forkCount) - 1;
134                if (count == 0) {
135                    context.setVar(flag, "true");
136                }
137    
138            }
139            else {
140                throw new IllegalStateException("Invalid node type: " + nodeClass);
141            }
142        }
143    
144        @Override
145        public List<String> multiExit(Context context)
146            throws WorkflowException {
147            Class<? extends NodeDef> nodeClass = context.getNodeDef().getClass();
148            if (nodeClass.equals(StartNodeDef.class)) {
149                return super.multiExit(context);
150            }
151            else if (nodeClass.equals(EndNodeDef.class)) {
152                return super.multiExit(context);
153            }
154            else if (nodeClass.equals(KillNodeDef.class)) {
155                return super.multiExit(context);
156            }
157            else if (nodeClass.equals(ForkNodeDef.class)) {
158                List<String> transitions = context.getNodeDef().getTransitions();
159                context.setVar(FORK_COUNT_PREFIX + context.getExecutionPath(), "" + transitions.size());
160    
161                List<String> fullTransitions = new ArrayList<String>(transitions.size());
162    
163                for (String transition : transitions) {
164                    String childExecutionPath = context.createExecutionPath(transition);
165                    String fullTransition = context.createFullTransition(childExecutionPath, transition);
166                    fullTransitions.add(fullTransition);
167                }
168                return fullTransitions;
169            }
170            else if (nodeClass.equals(JoinNodeDef.class)) {
171                String parentExecutionPath = context.getParentExecutionPath(context.getExecutionPath());
172                // NOW we delete..
173                context.deleteExecutionPath();
174    
175                String transition = context.getNodeDef().getTransitions().get(0);
176                String fullTransition = context.createFullTransition(parentExecutionPath, transition);
177                List<String> transitions = new ArrayList<String>(1);
178                transitions.add(fullTransition);
179                return transitions;
180            }
181            else {
182                throw new IllegalStateException("Invalid node type: " + nodeClass);
183            }
184        }
185    
186        @Override
187        public void kill(Context context) {
188            Class<? extends NodeDef> nodeClass = context.getNodeDef().getClass();
189            if (nodeClass.equals(StartNodeDef.class)) {
190                //NOP
191            }
192            else if (nodeClass.equals(EndNodeDef.class)) {
193                //NOP
194            }
195            else if (nodeClass.equals(KillNodeDef.class)) {
196                //NOP
197            }
198            else if (nodeClass.equals(ForkNodeDef.class)) {
199                //NOP
200            }
201            else if (nodeClass.equals(JoinNodeDef.class)) {
202                //NOP
203            }
204            else {
205                throw new IllegalStateException("Invalid node type: " + nodeClass);
206            }
207        }
208    
209        @Override
210        public void fail(Context context) {
211            Class<? extends NodeDef> nodeClass = context.getNodeDef().getClass();
212            if (nodeClass.equals(StartNodeDef.class)) {
213                //NOP
214            }
215            else if (nodeClass.equals(EndNodeDef.class)) {
216                //NOP
217            }
218            else if (nodeClass.equals(KillNodeDef.class)) {
219                //NOP
220            }
221            else if (nodeClass.equals(ForkNodeDef.class)) {
222                //NOP
223            }
224            else if (nodeClass.equals(JoinNodeDef.class)) {
225                //NOP
226            }
227            else {
228                throw new IllegalStateException("Invalid node type: " + nodeClass);
229            }
230        }
231    }