org.spearce.jgit/src/org/spearce/jgit/lib/RefComparator.java

   1 /**
   2  * Copyright (C) 2008, Charles O'Farrell <charleso@charleso.org>
   3  *
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or
   7  * without modification, are permitted provided that the following
   8  * conditions are met:
   9  *
  10  * - Redistributions of source code must retain the above copyright
  11  *   notice, this list of conditions and the following disclaimer.
  12  *
  13  * - Redistributions in binary form must reproduce the above
  14  *   copyright notice, this list of conditions and the following
  15  *   disclaimer in the documentation and/or other materials provided
  16  *   with the distribution.
  17  *
  18  * - Neither the name of the Git Development Community nor the
  19  *   names of its contributors may be used to endorse or promote
  20  *   products derived from this software without specific prior
  21  *   written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  24  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  25  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  28  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  31  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  32  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  33  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  35  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 package org.spearce.jgit.lib;
  39
  40 import java.util.ArrayList;
  41 import java.util.Collection;
  42 import java.util.Collections;
  43 import java.util.Comparator;
  44 import java.util.List;
  45
  46 /**
  47  * Util for sorting (or comparing) Ref instances by name.
  48  * <p>
  49  * Useful for command line tools or writing out refs to file.
  50  */
  51 public class RefComparator implements Comparator<Ref> {
  52
  53         /** Singleton instance of RefComparator */
  54         public static final RefComparator INSTANCE = new RefComparator();
  55
  56         public int compare(final Ref o1, final Ref o2) {
  57                 return o1.getOrigName().compareTo(o2.getOrigName());
  58         }
  59
  60         /**
  61          * Sorts the collection of refs, returning a new collection.
  62          *
  63          * @param refs
  64          *            collection to be sorted
  65          * @return sorted collection of refs
  66          */
  67         public static Collection<Ref> sort(final Collection<Ref> refs) {
  68                 final List<Ref> r = new ArrayList<Ref>(refs);
  69                 Collections.sort(r, INSTANCE);
  70                 return r;
  71         }
  72 }