BSHIfStatement.java :  » Scripting » beanshell » bsh » Java Open Source

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beanshell » bsh » BSHIfStatement.java
/*****************************************************************************
 *                                                                           *
 *  This file is part of the BeanShell Java Scripting distribution.          *
 *  Documentation and updates may be found at http://www.beanshell.org/      *
 *                                                                           *
 *  Sun Public License Notice:                                               *
 *                                                                           *
 *  The contents of this file are subject to the Sun Public License Version  *
 *  1.0 (the "License"); you may not use this file except in compliance with *
 *  the License. A copy of the License is available at http://www.sun.com    * 
 *                                                                           *
 *  The Original Code is BeanShell. The Initial Developer of the Original    *
 *  Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright     *
 *  (C) 2000.  All Rights Reserved.                                          *
 *                                                                           *
 *  GNU Public License Notice:                                               *
 *                                                                           *
 *  Alternatively, the contents of this file may be used under the terms of  *
 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 *  provisions of LGPL are applicable instead of those above. If you wish to *
 *  allow use of your version of this file only under the  terms of the LGPL *
 *  and not to allow others to use your version of this file under the SPL,  *
 *  indicate your decision by deleting the provisions above and replace      *
 *  them with the notice and other provisions required by the LGPL.  If you  *
 *  do not delete the provisions above, a recipient may use your version of  *
 *  this file under either the SPL or the LGPL.                              *
 *                                                                           *
 *  Patrick Niemeyer (pat@pat.net)                                           *
 *  Author of Learning Java, O'Reilly & Associates                           *
 *  http://www.pat.net/~pat/                                                 *
 *                                                                           *
 *****************************************************************************/


package bsh;

class BSHIfStatement extends SimpleNode
{
    BSHIfStatement(int id) { super(id); }

    public Object eval(CallStack callstack, Interpreter interpreter)  
    throws EvalError
    {
        Object ret = null;

        if( evaluateCondition( 
      (SimpleNode)jjtGetChild(0), callstack, interpreter ) )
            ret = ((SimpleNode)jjtGetChild(1)).eval(callstack, interpreter);
        else
            if(jjtGetNumChildren() > 2)
                ret = ((SimpleNode)jjtGetChild(2)).eval(callstack, interpreter);

        if(ret instanceof ReturnControl)
            return ret;
        else    
            return Primitive.VOID;
    }

    public static boolean evaluateCondition(
    SimpleNode condExp, CallStack callstack, Interpreter interpreter) 
    throws EvalError
    {
        Object obj = condExp.eval(callstack, interpreter);
        if(obj instanceof Primitive) {
      if ( obj == Primitive.VOID )
        throw new EvalError("Condition evaluates to void type", 
          condExp, callstack );
            obj = ((Primitive)obj).getValue();
    }

        if(obj instanceof Boolean)
            return ((Boolean)obj).booleanValue();
        else
            throw new EvalError(
        "Condition must evaluate to a Boolean or boolean.", 
        condExp, callstack );
    }
}
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