    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 */
    017package org.apache.commons.imaging.palette;
    018
    019import java.util.Comparator;
    020import java.util.Objects;
    021
    022/**
    023 * A comparator for {#link ColorCount} elements.
    024 *
    025 * <p>
    026 * It uses a given {#link ColorComponent} to choose what channel must be used for the comparison.
    027 * </p>
    028 *
    029 * <p>
    030 * For example, if the comparator is created for the {@link ColorComponent#RED} channel, then it will compare the value of red of each {@code ColorCount} object
    031 * in the array of elements.
    032 * </p>
    033 *
    034 * @since 1.0-alpha2
    035 */
    036public class ColorCountComparator implements Comparator<ColorCount> {
    037
    038    /**
    039     * Color component used during the comparison.
    040     */
    041    private final ColorComponent colorComponent;
    042
    043    /**
    044     * Constructs a new instance.
    045     *
    046     * @param colorComponent Color component to wrap.
    047     */
    048    public ColorCountComparator(final ColorComponent colorComponent) {
    049        this.colorComponent = Objects.requireNonNull(colorComponent, "colorComponent");
    050    }
    051
    052    @Override
    053    public int compare(final ColorCount c1, final ColorCount c2) {
    054        switch (colorComponent) {
    055        case ALPHA:
    056            return c1.alpha - c2.alpha;
    057        case RED:
    058            return c1.red - c2.red;
    059        case GREEN:
    060            return c1.green - c2.green;
    061        case BLUE:
    062            return c1.blue - c2.blue;
    063        default:
    064            return 0;
    065        }
    066    }
    067
    068}