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 * A compile tree element containing a constant number or string.
025 */
026public class Constant extends Expression {
027
028    private final Object value;
029
030    /**
031     * Constructs a new Constant.
032     *
033     * @param number constant
034     */
035    public Constant(final Number number) {
036        this.value = number;
037    }
038
039    /**
040     * Constructs a new Constant.
041     *
042     * @param string constant
043     */
044    public Constant(final String string) {
045        this.value = string;
046    }
047
048    @Override
049    public Object compute(final EvalContext context) {
050        return value;
051    }
052
053    /**
054     * Returns false
055     *
056     * @return false
057     */
058    @Override
059    public boolean computeContextDependent() {
060        return false;
061    }
062
063    @Override
064    public Object computeValue(final EvalContext context) {
065        return value;
066    }
067
068    /**
069     * Returns false
070     *
071     * @return false
072     */
073    @Override
074    public boolean isContextDependent() {
075        return false;
076    }
077
078    @Override
079    public String toString() {
080        if (value instanceof Number) {
081            return InfoSetUtil.stringValue(value);
082        }
083        return "'" + value + "'";
084    }
085}