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|}).</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    /**
035     * The size of set A.
036     */
037    private final int sizeA;
038
039    /**
040     * The size of set B.
041     */
042    private final int sizeB;
043
044    /**
045     * The size of the intersection between set A and B.
046     */
047    private final int intersection;
048
049    /**
050     * Constructs the results for an intersection between two sets.
051     *
052     * @param sizeA the size of set A ({@code |A|})
053     * @param sizeB the size of set B ({@code |B|})
054     * @param intersection the size of the intersection of A and B ({@code |A &#8745; B|})
055     * @throws IllegalArgumentException if the sizes are negative or the intersection is greater
056     * than the minimum of the two set sizes
057     */
058    public IntersectionResult(final int sizeA, final int sizeB, final int intersection) {
059        if (sizeA < 0) {
060            throw new IllegalArgumentException("Set size |A| is not positive: " + sizeA);
061        }
062        if (sizeB < 0) {
063            throw new IllegalArgumentException("Set size |B| is not positive: " + sizeB);
064        }
065        if (intersection < 0 || intersection > Math.min(sizeA, sizeB)) {
066            throw new IllegalArgumentException("Invalid intersection of A and B: " + intersection);
067        }
068        this.sizeA = sizeA;
069        this.sizeB = sizeB;
070        this.intersection = intersection;
071    }
072
073    @Override
074    public boolean equals(final Object o) {
075        if (this == o) {
076            return true;
077        }
078        if (o == null || getClass() != o.getClass()) {
079            return false;
080        }
081        final IntersectionResult result = (IntersectionResult) o;
082        return sizeA == result.sizeA && sizeB == result.sizeB && intersection == result.intersection;
083    }
084
085    /**
086     * Gets the size of the intersection between set A and B.
087     *
088     * @return {@code |A &#8745; B|}
089     */
090    public int getIntersection() {
091        return intersection;
092    }
093
094    /**
095     * Gets the size of set A.
096     *
097     * @return |A|
098     */
099    public int getSizeA() {
100        return sizeA;
101    }
102
103    /**
104     * Gets the size of set B.
105     *
106     * @return |B|
107     */
108    public int getSizeB() {
109        return sizeB;
110    }
111
112    @Override
113    public int hashCode() {
114        return Objects.hash(sizeA, sizeB, intersection);
115    }
116
117    @Override
118    public String toString() {
119        return "Size A: " + sizeA + ", Size B: " + sizeB + ", Intersection: " + intersection;
120    }
121}