defaultunaryexpr.java

XML的解析、编译、查询等技术的JAVA源代码。

/*
 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultUnaryExpr.java,v 1.16 2006/11/30 18:49:27 elharo Exp $
 * $Revision: 1.16 $
 * $Date: 2006/11/30 18:49:27 $
 *
 * ====================================================================
 *
 * Copyright 2000-2002 bob mcwhirter & James Strachan.
 * 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 Jaxen Project 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 AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 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.
 *
 * ====================================================================
 * This software consists of voluntary contributions made by many 
 * individuals on behalf of the Jaxen Project and was originally 
 * created by bob mcwhirter <[e-mail]> and 
 * James Strachan <[e-mail]>.  For more information on the 
 * Jaxen Project, please see <http://www.jaxen.org/>.
 * 
 * $Id: DefaultUnaryExpr.java,v 1.16 2006/11/30 18:49:27 elharo Exp $
 */



package org.jaxen.expr;

import org.jaxen.Context;
import org.jaxen.JaxenException;
import org.jaxen.function.NumberFunction;

class DefaultUnaryExpr extends DefaultExpr implements UnaryExpr
{
    /**
     * 
     */
    private static final long serialVersionUID = 2303714238683092334L;
    private Expr expr;

    DefaultUnaryExpr(Expr expr)
    {
        this.expr = expr;
    }

    public Expr getExpr()
    {
        return this.expr;
    }

    public String toString()
    {
        return "[(DefaultUnaryExpr): " + getExpr() + "]";
    }

    public String getText()
    {
        return "-(" + getExpr().getText() + ")";
    }

    public Expr simplify()
    {
        expr = expr.simplify();

        return this;
    }

    public Object evaluate(Context context) throws JaxenException
    {
        Number number = NumberFunction.evaluate( getExpr().evaluate( context ),
                                                 context.getNavigator() );

        return new Double( number.doubleValue() * -1 );
    }
    
}