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/jEdit/tags/jedit-4-2-pre14/bsh/BSHUnaryExpression.java

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Java | 133 lines | 80 code | 17 blank | 36 comment | 29 complexity | 955d06d1755fc52c2b842a898763fa3e MD5 | raw file
  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/      *
  5 *                                                                           *
  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  *
 19 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 20 *  provisions of LGPL are applicable instead of those above. If you wish to *
 21 *  allow use of your version of this file only under the  terms of the LGPL *
 22 *  and not to allow others to use your version of this file under the SPL,  *
 23 *  indicate your decision by deleting the provisions above and replace      *
 24 *  them with the notice and other provisions required by the LGPL.  If you  *
 25 *  do not delete the provisions above, a recipient may use your version of  *
 26 *  this file under either the SPL or the LGPL.                              *
 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 BSHUnaryExpression extends SimpleNode implements ParserConstants
 38{
 39    public int kind;
 40	public boolean postfix = false;
 41
 42    BSHUnaryExpression(int id) { super(id); }
 43
 44    public Object eval( CallStack callstack, Interpreter interpreter)  
 45		throws EvalError
 46    {
 47        SimpleNode node = (SimpleNode)jjtGetChild(0);
 48
 49		// If this is a unary increment of decrement (either pre or postfix)
 50		// then we need an LHS to which to assign the result.  Otherwise
 51		// just do the unary operation for the value.
 52		try {
 53			if ( kind == INCR || kind == DECR ) {
 54				LHS lhs = ((BSHPrimaryExpression)node).toLHS( 
 55					callstack, interpreter );
 56				return lhsUnaryOperation( lhs, interpreter.getStrictJava() );
 57			} else
 58				return 
 59					unaryOperation( node.eval(callstack, interpreter), kind );
 60		} catch ( UtilEvalError e ) {
 61			throw e.toEvalError( this, callstack );
 62		}
 63    }
 64
 65    private Object lhsUnaryOperation( LHS lhs, boolean strictJava ) 
 66		throws UtilEvalError
 67    {
 68        if ( Interpreter.DEBUG ) Interpreter.debug("lhsUnaryOperation");
 69        Object prevalue, postvalue;
 70        prevalue = lhs.getValue();
 71        postvalue = unaryOperation(prevalue, kind);
 72
 73		Object retVal;
 74		if ( postfix )
 75			retVal = prevalue;
 76		else
 77			retVal = postvalue;
 78
 79		lhs.assign( postvalue, strictJava );
 80		return retVal;
 81    }
 82
 83    private Object unaryOperation( Object op, int kind ) throws UtilEvalError
 84    {
 85        if (op instanceof Boolean || op instanceof Character 
 86			|| op instanceof Number)
 87            return primitiveWrapperUnaryOperation( op, kind );
 88
 89        if ( !(op instanceof Primitive) )
 90            throw new UtilEvalError( "Unary operation " + tokenImage[kind]
 91                + " inappropriate for object" );
 92
 93		
 94        return Primitive.unaryOperation((Primitive)op, kind);
 95    }
 96
 97    private Object primitiveWrapperUnaryOperation(Object val, int kind)
 98        throws UtilEvalError
 99    {
100        Class operandType = val.getClass();
101        Object operand = Primitive.promoteToInteger(val);
102
103        if ( operand instanceof Boolean )
104			return new Boolean(
105				Primitive.booleanUnaryOperation((Boolean)operand, kind));
106        else 
107		if ( operand instanceof Integer )
108        {
109            int result = Primitive.intUnaryOperation((Integer)operand, kind);
110
111            // ++ and -- must be cast back the original type
112            if(kind == INCR || kind == DECR)
113            {
114                if(operandType == Byte.TYPE)
115                    return new Byte((byte)result);
116                if(operandType == Short.TYPE)
117                    return new Short((short)result);
118                if(operandType == Character.TYPE)
119                    return new Character((char)result);
120            }
121
122            return new Integer(result);
123        }
124        else if(operand instanceof Long)
125            return new Long(Primitive.longUnaryOperation((Long)operand, kind));
126        else if(operand instanceof Float)
127            return new Float(Primitive.floatUnaryOperation((Float)operand, kind));
128        else if(operand instanceof Double)
129            return new Double(Primitive.doubleUnaryOperation((Double)operand, kind));
130        else
131            throw new InterpreterError("An error occurred.  Please call technical support.");
132    }
133}