001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.scxml.model;
018
019 import java.util.ArrayList;
020 import java.util.Collection;
021 import java.util.Iterator;
022 import java.util.List;
023
024 import org.apache.commons.logging.Log;
025 import org.apache.commons.scxml.Context;
026 import org.apache.commons.scxml.ErrorReporter;
027 import org.apache.commons.scxml.Evaluator;
028 import org.apache.commons.scxml.EventDispatcher;
029 import org.apache.commons.scxml.SCInstance;
030 import org.apache.commons.scxml.SCXMLExpressionException;
031
032 /**
033 * The class in this SCXML object model that corresponds to the
034 * <if> SCXML element, which serves as a container for conditionally
035 * executed elements. <else> and <elseif> can optionally
036 * appear within an <if> as immediate children, and serve to partition
037 * the elements within an <if>.
038 *
039 */
040 public class If extends Action {
041
042 /**
043 * Serial version UID.
044 */
045 private static final long serialVersionUID = 1L;
046
047 /**
048 * An conditional expression which can be evaluated to true or false.
049 */
050 private String cond;
051
052 /**
053 * The set of executable elements (those that inheriting from
054 * Action) that are contained in this <if> element.
055 */
056 private List actions;
057
058 /**
059 * The boolean value that dictates whether the particular child action
060 * should be executed.
061 */
062 private boolean execute;
063
064 /**
065 * Constructor.
066 */
067 public If() {
068 super();
069 this.actions = new ArrayList();
070 this.execute = false;
071 }
072
073 /**
074 * Get the executable actions contained in this <if>.
075 *
076 * @return Returns the actions.
077 */
078 public final List getActions() {
079 return actions;
080 }
081
082 /**
083 * Add an Action to the list of executable actions contained in
084 * this <if>.
085 *
086 * @param action The action to add.
087 */
088 public final void addAction(final Action action) {
089 if (action != null) {
090 this.actions.add(action);
091 }
092 }
093
094 /**
095 * Get the conditional expression.
096 *
097 * @return Returns the cond.
098 */
099 public final String getCond() {
100 return cond;
101 }
102
103 /**
104 * Set the conditional expression.
105 *
106 * @param cond The cond to set.
107 */
108 public final void setCond(final String cond) {
109 this.cond = cond;
110 }
111
112 /**
113 * {@inheritDoc}
114 */
115 public void execute(final EventDispatcher evtDispatcher,
116 final ErrorReporter errRep, final SCInstance scInstance,
117 final Log appLog, final Collection derivedEvents)
118 throws ModelException, SCXMLExpressionException {
119 TransitionTarget parentTarget = getParentTransitionTarget();
120 Context ctx = scInstance.getContext(parentTarget);
121 Evaluator eval = scInstance.getEvaluator();
122 ctx.setLocal(getNamespacesKey(), getNamespaces());
123 execute = eval.evalCond(ctx, cond).booleanValue();
124 ctx.setLocal(getNamespacesKey(), null);
125 // The "if" statement is a "container"
126 for (Iterator ifiter = actions.iterator(); ifiter.hasNext();) {
127 Action aa = (Action) ifiter.next();
128 if (execute && !(aa instanceof ElseIf)
129 && !(aa instanceof Else)) {
130 aa.execute(evtDispatcher, errRep, scInstance, appLog,
131 derivedEvents);
132 } else if (execute
133 && (aa instanceof ElseIf || aa instanceof Else)) {
134 break;
135 } else if (aa instanceof Else) {
136 execute = true;
137 } else if (aa instanceof ElseIf) {
138 ctx.setLocal(getNamespacesKey(), getNamespaces());
139 execute = eval.evalCond(ctx, ((ElseIf) aa).getCond())
140 .booleanValue();
141 ctx.setLocal(getNamespacesKey(), null);
142 }
143 }
144 }
145
146 }
147