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: State parentState = getParentState();
120: Context ctx = scInstance.getContext(parentState);
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: }
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