net.greypanther.natsort.SimpleNaturalComparator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of natural-comparator Show documentation

Java implementation of the "natural sort" (also known as Alphanum sort) algorithm

The newest version!

package net.greypanther.natsort;

import java.util.Comparator;

/**
 * Compares Strings (or any other CharSequence subclass) using the
 * natural sort /
 * alphanum algorithm which gives a more
 * "natural" ordering when presenting the sorted list of strings to humans.
 * 
 * 
 * This is a fast implementation of the original algorithm which produces no garbage during its run.
 * There is also a case-insensitive variant you might want to use:
 * {@link CaseInsensitiveSimpleNaturalComparator}. This is a fully self-contained implementation
 * compiled with Java 1.6 for maximum compatibility which does not add any additional dependencies
 * to your project.
 * 
 * 

 * There are still limitations of this implementation to be aware of (which hopefully will be
 * addressed in future releases):
 * 
 * 

 * Does not play nice with Unicode, especially characters which are outside of the BMP (ie.
 * codepoints with values larger than {@link Character#MAX_VALUE}).
 * Does not handle fractions or grouping characters properly.
 * Only understands integer values up to 2^64-1.
 * 
 */
public final class SimpleNaturalComparator
    extends AbstractSimpleNaturalComparator implements Comparator {
  @SuppressWarnings("rawtypes")
  private static final Comparator INSTANCE = new SimpleNaturalComparator();

  private SimpleNaturalComparator() {
    // to be instantiated only internally
  }

  @Override
  int compareChars(char c1, char c2) {
    return c1 - c2;
  }

  @SuppressWarnings("unchecked")
  public static  Comparator getInstance() {
    return INSTANCE;
  }
}