org.sonar.plugins.core.issue.tracking.HashedSequence.java Source code

Introduction

Here is the source code for org.sonar.plugins.core.issue.tracking.HashedSequence.java

Source

/*
 * SonarQube, open source software quality management tool.
 * Copyright (C) 2008-2014 SonarSource
 * mailto:contact AT sonarsource DOT com
 *
 * SonarQube is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * SonarQube is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.plugins.core.issue.tracking;

import com.google.common.collect.LinkedHashMultimap;
import com.google.common.collect.Multimap;

import java.util.Collection;

/**
 * Wraps a {@link Sequence} to assign hash codes to elements.
 */
public final class HashedSequence<S extends Sequence> implements Sequence {

    final S base;
    final int[] hashes;
    final Multimap<Integer, Integer> linesByHash;

    private HashedSequence(S base, int[] hashes, Multimap<Integer, Integer> linesByHash) {
        this.base = base;
        this.hashes = hashes;
        this.linesByHash = linesByHash;
    }

    public static <S extends Sequence> HashedSequence<S> wrap(S base, SequenceComparator<S> cmp) {
        int size = base.length();
        int[] hashes = new int[size];
        Multimap<Integer, Integer> linesByHash = LinkedHashMultimap.create();
        for (int i = 0; i < size; i++) {
            hashes[i] = cmp.hash(base, i);
            // indices in array are shifted one line before
            linesByHash.put(hashes[i], i + 1);
        }
        return new HashedSequence<S>(base, hashes, linesByHash);
    }

    @Override
    public int length() {
        return base.length();
    }

    public Collection<Integer> getLinesForHash(Integer hash) {
        return linesByHash.get(hash);
    }

    public Integer getHash(Integer line) {
        // indices in array are shifted one line before
        return hashes[line - 1];
    }
}