org.sonar.duplications.utils.FastStringComparator Maven / Gradle / Ivy
/*
* SonarQube
* Copyright (C) 2009-2017 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program 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.
*
* This program 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.duplications.utils;
import java.util.Comparator;
/**
* More efficient (in terms of performance) implementation of a String comparator.
* Speed is gained by using hash code as a primary comparison attribute, which is cached for String.
* Be aware that this ordering is not lexicographic, however stable.
*/
public final class FastStringComparator implements Comparator {
public static final FastStringComparator INSTANCE = new FastStringComparator();
/**
* Compares two strings (not lexicographically).
*/
@Override
public int compare(String s1, String s2) {
if (s1 == s2) { // NOSONAR false-positive: Compare Objects With Equals
return 0;
}
int h1 = s1.hashCode();
int h2 = s2.hashCode();
if (h1 < h2) {
return -1;
} else if (h1 > h2) {
return 1;
} else {
return s1.compareTo(s2);
}
}
/**
* Enforce use of a singleton instance.
*/
private FastStringComparator() {
}
}