Commons JXPath example source code file (CoreOperationSubtract.java)

This example Commons JXPath source code file (CoreOperationSubtract.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons JXPath tags/keywords

add_precedence, coreoperation, coreoperation, coreoperationsubtract, coreoperationsubtract, double, double, expression, expression, object, string

The Commons JXPath CoreOperationSubtract.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.jxpath.ri.compiler;

import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.InfoSetUtil;

/**
 * Implementation of {@link Expression} for the operation "-".
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
 */
public class CoreOperationSubtract extends CoreOperation {

    /**
     * Create a new CoreOperationSubtract.
     * @param arg1 minuend
     * @param arg2 subtrahend
     */
    public CoreOperationSubtract(Expression arg1, Expression arg2) {
        super(new Expression[] { arg1, arg2 });
    }

    public Object computeValue(EvalContext context) {
        double l = InfoSetUtil.doubleValue(args[0].computeValue(context));
        double r = InfoSetUtil.doubleValue(args[1].computeValue(context));
        return new Double(l - r);
    }

    protected int getPrecedence() {
        return ADD_PRECEDENCE;
    }

    protected boolean isSymmetric() {
        return false;
    }

    public String getSymbol() {
        return "-";
    }
}