    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.text.similarity;
    018
    019import java.util.Objects;
    020
    021/**
    022 * Represents the intersection result between two sets.
    023 *
    024 * <p>Stores the size of set A, set B and the intersection of A and B
    025 * (<code>|A &#8745; B|</code>).</p>
    026 *
    027 * <p>This class is immutable.</p>
    028 *
    029 * @since 1.7
    030 * @see <a href="https://en.wikipedia.org/wiki/Intersection_(set_theory)">Intersection</a>
    031 */
    032public class IntersectionResult {
    033    /**
    034     * The size of set A.
    035     */
    036    private final int sizeA;
    037    /**
    038     * The size of set B.
    039     */
    040    private final int sizeB;
    041    /**
    042     * The size of the intersection between set A and B.
    043     */
    044    private final int intersection;
    045
    046    /**
    047     * Create the results for an intersection between two sets.
    048     *
    049     * @param sizeA the size of set A ({@code |A|})
    050     * @param sizeB the size of set B ({@code |B|})
    051     * @param intersection the size of the intersection of A and B (<code>|A &#8745; B|</code>)
    052     * @throws IllegalArgumentException if the sizes are negative or the intersection is greater
    053     * than the minimum of the two set sizes
    054     */
    055    public IntersectionResult(final int sizeA, final int sizeB, final int intersection) {
    056        if (sizeA < 0) {
    057            throw new IllegalArgumentException("Set size |A| is not positive: " + sizeA);
    058        }
    059        if (sizeB < 0) {
    060            throw new IllegalArgumentException("Set size |B| is not positive: " + sizeB);
    061        }
    062        if (intersection < 0 || intersection > Math.min(sizeA, sizeB)) {
    063            throw new IllegalArgumentException("Invalid intersection of |A| and |B|: " + intersection);
    064        }
    065        this.sizeA = sizeA;
    066        this.sizeB = sizeB;
    067        this.intersection = intersection;
    068    }
    069
    070    /**
    071     * Get the size of set A.
    072     *
    073     * @return |A|
    074     */
    075    public int getSizeA() {
    076        return sizeA;
    077    }
    078
    079    /**
    080     * Get the size of set B.
    081     *
    082     * @return |B|
    083     */
    084    public int getSizeB() {
    085        return sizeB;
    086    }
    087
    088    /**
    089     * Get the size of the intersection between set A and B.
    090     *
    091     * @return <code>|A &#8745; B|</code>
    092     */
    093    public int getIntersection() {
    094        return intersection;
    095    }
    096
    097    @Override
    098    public boolean equals(final Object o) {
    099        if (this == o) {
    100            return true;
    101        }
    102        if (o == null || getClass() != o.getClass()) {
    103            return false;
    104        }
    105        final IntersectionResult result = (IntersectionResult) o;
    106        return sizeA == result.sizeA && sizeB == result.sizeB && intersection == result.intersection;
    107    }
    108
    109    @Override
    110    public int hashCode() {
    111        return Objects.hash(sizeA, sizeB, intersection);
    112    }
    113
    114    @Override
    115    public String toString() {
    116        return "Size A: " + sizeA + ", Size B: " + sizeB + ", Intersection: " + intersection;
    117    }
    118}