    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.jxpath.ri.compiler;
    019
    020import org.apache.commons.jxpath.ri.EvalContext;
    021import org.apache.commons.jxpath.ri.InfoSetUtil;
    022
    023/**
    024 * Implementation of {@link Expression} for the operation "-".
    025 */
    026public class CoreOperationSubtract extends CoreOperation {
    027
    028    /**
    029     * Constructs a new CoreOperationSubtract.
    030     *
    031     * @param arg1 minuend
    032     * @param arg2 subtrahend
    033     */
    034    public CoreOperationSubtract(final Expression arg1, final Expression arg2) {
    035        super(new Expression[] { arg1, arg2 });
    036    }
    037
    038    @Override
    039    public Object computeValue(final EvalContext context) {
    040        final double l = InfoSetUtil.doubleValue(args[0].computeValue(context));
    041        final double r = InfoSetUtil.doubleValue(args[1].computeValue(context));
    042        return Double.valueOf(l - r);
    043    }
    044
    045    @Override
    046    protected int getPrecedence() {
    047        return ADD_PRECEDENCE;
    048    }
    049
    050    @Override
    051    public String getSymbol() {
    052        return "-";
    053    }
    054
    055    @Override
    056    protected boolean isSymmetric() {
    057        return false;
    058    }
    059}