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Java > Open Source Codes > freemarker > core > ReturnInstruction


1 /*
2  * Copyright (c) 2003 The Visigoth Software Society. All rights
3  * reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  *
12  * 2. Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in
14  * the documentation and/or other materials provided with the
15  * distribution.
16  *
17  * 3. The end-user documentation included with the redistribution, if
18  * any, must include the following acknowledgement:
19  * "This product includes software developed by the
20  * Visigoth Software Society (http://www.visigoths.org/)."
21  * Alternately, this acknowledgement may appear in the software itself,
22  * if and wherever such third-party acknowledgements normally appear.
23  *
24  * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
25  * project contributors may be used to endorse or promote products derived
26  * from this software without prior written permission. For written
27  * permission, please contact visigoths@visigoths.org.
28  *
29  * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
30  * nor may "FreeMarker" or "Visigoth" appear in their names
31  * without prior written permission of the Visigoth Software Society.
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45  * ====================================================================
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48  * individuals on behalf of the Visigoth Software Society. For more
49  * information on the Visigoth Software Society, please see
50  * http://www.visigoths.org/
51  */
52
53 package freemarker.core;
54
55 import freemarker.template.TemplateException;
56
57 /**
58  * Represents a <return> instruction to jump out of a macro.
59  * @author <A HREF="mailto:jon@revusky.com">Jonathan Revusky</A>
60  */
61 final class ReturnInstruction extends TemplateElement {
62
63     private Expression exp;
64
65     ReturnInstruction(Expression exp) {
66         this.exp = exp;
67     }
68
69     void accept(Environment env) throws TemplateException {
70         if (exp != null) {
71             env.setLastReturnValue(exp.getAsTemplateModel(env));
72         }
73         if (nextSibling() != null) {
74             // We need to jump out using an exception.
75 throw new Return();
76         }
77         if (!(getParent() instanceof Macro || getParent().getParent() instanceof Macro)) {
78             // Here also, we need to jump out using an exception.
79 throw new Return();
80         }
81     }
82
83     public String JavaDoc getCanonicalForm() {
84         String JavaDoc expString = exp == null ? "" : " " + exp.getCanonicalForm();
85         return "<#return" + expString + "/>";
86     }
87
88     public String JavaDoc getDescription() {
89         return "return" + " [" + getStartLocation() + "]";
90     }
91
92     static class Return extends RuntimeException JavaDoc {
93     }
94 }
95
96
97
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