/*
 *  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.tools.ant.types.resources.comparators;

import org.apache.tools.ant.types.Resource;

/**
 * Compares Resources by existence.  Not existing is "less than" existing.
 * @since Ant 1.7
 */
public class Exists extends ResourceComparator {

    /**
     * Compare two Resources.
     * @param foo the first Resource.
     * @param bar the second Resource.
     * @return a negative integer, zero, or a positive integer as the first
     *         argument is less than, equal to, or greater than the second.
     */
    protected int resourceCompare(Resource foo, Resource bar) {
        boolean f = foo.isExists();
        if (f == bar.isExists()) {
            return 0;
        }
        return f ? 1 : -1;
    }

}