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Java > Open Source Codes > bsh > BSHIfStatement


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2  * *
3  * This file is part of the BeanShell Java Scripting distribution. *
4  * Documentation and updates may be found at http://www.beanshell.org/ *
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6  * Sun Public License Notice: *
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8  * The contents of this file are subject to the Sun Public License Version *
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12  * The Original Code is BeanShell. The Initial Developer of the Original *
13  * Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright *
14  * (C) 2000. All Rights Reserved. *
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18  * Alternatively, the contents of this file may be used under the terms of *
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28  * Patrick Niemeyer (pat@pat.net) *
29  * Author of Learning Java, O'Reilly & Associates *
30  * http://www.pat.net/~pat/ *
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32  *****************************************************************************/
33
34
35 package bsh;
36
37 class BSHIfStatement extends SimpleNode
38 {
39     BSHIfStatement(int id) { super(id); }
40
41     public Object JavaDoc eval(CallStack callstack, Interpreter interpreter)
42         throws EvalError
43     {
44         Object JavaDoc ret = null;
45
46         if( evaluateCondition(
47             (SimpleNode)jjtGetChild(0), callstack, interpreter ) )
48             ret = ((SimpleNode)jjtGetChild(1)).eval(callstack, interpreter);
49         else
50             if(jjtGetNumChildren() > 2)
51                 ret = ((SimpleNode)jjtGetChild(2)).eval(callstack, interpreter);
52
53         if(ret instanceof ReturnControl)
54             return ret;
55         else
56             return Primitive.VOID;
57     }
58
59     public static boolean evaluateCondition(
60         SimpleNode condExp, CallStack callstack, Interpreter interpreter)
61         throws EvalError
62     {
63         Object JavaDoc obj = condExp.eval(callstack, interpreter);
64         if(obj instanceof Primitive) {
65             if ( obj == Primitive.VOID )
66                 throw new EvalError("Condition evaluates to void type",
67                     condExp, callstack );
68             obj = ((Primitive)obj).getValue();
69         }
70
71         if(obj instanceof Boolean JavaDoc)
72             return ((Boolean JavaDoc)obj).booleanValue();
73         else
74             throw new EvalError(
75                 "Condition must evaluate to a Boolean or boolean.",
76                 condExp, callstack );
77     }
78 }
79
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