/jEdit/tags/jedit-4-2-pre4/bsh/BSHIfStatement.java

 1/*****************************************************************************
 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:                                               *
 7 *                                                                           *
 8 *  The contents of this file are subject to the Sun Public License Version  *
 9 *  1.0 (the "License"); you may not use this file except in compliance with *
10 *  the License. A copy of the License is available at http://www.sun.com    * 
11 *                                                                           *
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.                                          *
15 *                                                                           *
16 *  GNU Public License Notice:                                               *
17 *                                                                           *
18 *  Alternatively, the contents of this file may be used under the terms of  *
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20 *  provisions of LGPL are applicable instead of those above. If you wish to *
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27 *                                                                           *
28 *  Patrick Niemeyer (pat@pat.net)                                           *
29 *  Author of Learning Java, O'Reilly & Associates                           *
30 *  http://www.pat.net/~pat/                                                 *
31 *                                                                           *
32 *****************************************************************************/
33
34
35package bsh;
36
37class BSHIfStatement extends SimpleNode
38{
39    BSHIfStatement(int id) { super(id); }
40
41    public Object eval(CallStack callstack, Interpreter interpreter)  
42		throws EvalError
43    {
44        Object 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 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)
72            return ((Boolean)obj).booleanValue();
73        else
74            throw new EvalError(
75				"Condition must evaluate to a Boolean or boolean.", 
76				condExp, callstack );
77    }
78}