expressionnode.java

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//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  All rights reserved.
//
//	Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions are
//  met:
//
//	Redistributions of source code must retain the above copyright notice,
//  this list of conditions and the following disclaimer.
//	Redistributions in binary form must reproduce the above copyright
//  notice, this list of conditions and the following disclaimer in the
//  documentation and/or other materials provided with the distribution.
//	Neither the name of the Drew Davidson nor the names of its contributors
//  may be used to endorse or promote products derived from this software
//  without specific prior written permission.
//
//	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
//  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
//  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
//  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
//  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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//  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
//  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
//  DAMAGE.
//--------------------------------------------------------------------------
package ognl;

/**
 * @author Luke Blanshard ([e-mail])
 * @author Drew Davidson ([e-mail])
 */
public abstract class ExpressionNode extends SimpleNode
{
    public ExpressionNode(int i) {
        super(i);
    }

    public ExpressionNode(OgnlParser p, int i) {
        super(p, i);
    }
    /**
        Returns true iff this node is constant without respect to the children.
     */
    public boolean isNodeConstant( OgnlContext context ) throws OgnlException
    {
        return false;
    }

    public boolean isConstant( OgnlContext context ) throws OgnlException
    {
        boolean     result = isNodeConstant(context);

        if ((children != null) && (children.length > 0)) {
            result = true;
            for ( int i=0; result && (i < children.length); ++i ) {
                if (children[i] instanceof SimpleNode) {
                    result = ((SimpleNode)children[i]).isConstant( context );
                } else {
                    result = false;
                }
            }
        }
        return result;
    }

    public String getExpressionOperator(int index)
    {
        throw new RuntimeException("unknown operator for " + OgnlParserTreeConstants.jjtNodeName[id]);
    }

    public String toString()
    {
        String      result;

        result = (parent == null) ? "" : "(";
        if ((children != null) && (children.length > 0)) {
            for ( int i = 0; i < children.length; ++i ) {
                if (i > 0) {
                    result += " " + getExpressionOperator(i) + " ";
                }
                result += children[i].toString();
            }
        }
        if (parent != null) {
            result = result + ")";
        }
        return result;
    }
}