01: /*
02: * Copyright 2002-2006 The Apache Software Foundation.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16:
17: package org.apache.commons.jexl.parser;
18:
19: import org.apache.commons.jexl.JexlContext;
20: import org.apache.commons.jexl.util.Coercion;
21:
22: /**
23: * if ( expression ) statement [else statement].
24: *
25: * @author Dion Gillard
26: * @since 1.1
27: */
28: public class ASTIfStatement extends SimpleNode {
29: /** child index of the else statement to execute. */
30: private static final int ELSE_STATEMENT_INDEX = 2;
31:
32: /**
33: * Create the node given an id.
34: *
35: * @param id node id.
36: */
37: public ASTIfStatement(int id) {
38: super (id);
39: }
40:
41: /**
42: * Create a node with the given parser and id.
43: *
44: * @param p a parser.
45: * @param id node id.
46: */
47: public ASTIfStatement(Parser p, int id) {
48: super (p, id);
49: }
50:
51: /** {@inheritDoc} */
52: public Object jjtAccept(ParserVisitor visitor, Object data) {
53: return visitor.visit(this , data);
54: }
55:
56: /** {@inheritDoc} */
57: public Object value(JexlContext jc) throws Exception {
58: Object result = null;
59: /* first child is the expression */
60: Object expression = ((SimpleNode) jjtGetChild(0)).value(jc);
61: if (Coercion.coerceBoolean(expression).booleanValue()) {
62: // true statement
63: result = ((SimpleNode) jjtGetChild(1)).value(jc);
64: } else {
65: // if there is a false, execute it
66: if (jjtGetNumChildren() == ELSE_STATEMENT_INDEX + 1) {
67: result = ((SimpleNode) jjtGetChild(2)).value(jc);
68: }
69: }
70:
71: return result;
72: }
73:
74: }
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