001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.hadoop.tools.twitter.token.mode.pointwisemi.count;
031
032import java.io.IOException;
033import org.apache.hadoop.io.BytesWritable;
034import org.apache.hadoop.io.RawComparator;
035
036
037/**
038 * Read a tokenpair and make sure the single words appear before the pair words
039 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
040 *
041 */
042public class TokenPairValueGroupingComparator implements RawComparator<BytesWritable> {
043
044        @Override
045        public int compare(BytesWritable o1, BytesWritable o2) {
046                return compareData(o1.getBytes(),0,o1.getLength(),o2.getBytes(),0,o2.getLength());
047        }
048        
049        @Override
050        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
051                return compareData(b1,s1+4,l1-4,b2,s2+4,l2-4);
052        }
053        
054        private int compareData(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
055                // read the time, return 0 if the time is the same
056                try {
057                        long t1 = TokenPairUnaryCount.timeFromBinaryIdentity(b1,s1,l1);
058                        long t2 = TokenPairUnaryCount.timeFromBinaryIdentity(b2,s2,l2);
059                        if(t1 < t2) {
060                                return -1;
061                        }
062                        else if(t1 > t2){
063                                return 1;
064                        }
065                        else{
066                                return 0;
067                        }
068                        
069                } catch (IOException e) {
070                        return 0;
071                }
072        }
073
074
075}