001/** 002 * Copyright (C) 2007 - 2016, Jens Lehmann 003 * 004 * This file is part of DL-Learner. 005 * 006 * DL-Learner is free software; you can redistribute it and/or modify 007 * it under the terms of the GNU General Public License as published by 008 * the Free Software Foundation; either version 3 of the License, or 009 * (at your option) any later version. 010 * 011 * DL-Learner is distributed in the hope that it will be useful, 012 * but WITHOUT ANY WARRANTY; without even the implied warranty of 013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 014 * GNU General Public License for more details. 015 * 016 * You should have received a copy of the GNU General Public License 017 * along with this program. If not, see <http://www.gnu.org/licenses/>. 018 */ 019package org.dllearner.utilities; 020 021import com.google.common.base.Joiner; 022import com.google.common.base.Strings; 023import com.google.common.collect.ArrayListMultimap; 024import com.google.common.collect.Multimap; 025import com.google.common.collect.TreeMultimap; 026import org.apache.commons.lang3.StringUtils; 027 028import java.util.*; 029import java.util.Map.Entry; 030 031/** 032 * Utility class for operations on maps. 033 * 034 * @author Lorenz Buehmann 035 */ 036public class MapUtils { 037 038 /** 039 * Returns a list of entries sorted by the map values descending. 040 * 041 * @param map the map 042 * @return a list of entries sorted by the map values descending. 043 */ 044 public static <K, V extends Comparable<V>> List<Entry<K, V>> sortByValues(Map<K, V> map) { 045 return sortByValues(map, false); 046 } 047 048 /** 049 * Returns a list of entries sorted by the map values either ascending or descending. 050 * 051 * @param map the map 052 * @return a list of entries sorted by the map values either ascending or descending. 053 */ 054 public static <K, V extends Comparable<V>> List<Entry<K, V>> sortByValues(Map<K, V> map, final boolean ascending){ 055 List<Entry<K, V>> entries = new ArrayList<>(map.entrySet()); 056 Collections.sort(entries, new Comparator<Entry<K, V>>() { 057 058 @Override 059 public int compare(Entry<K, V> o1, Entry<K, V> o2) { 060 if(ascending){ 061 return o1.getValue().compareTo(o2.getValue()); 062 } else { 063 return o2.getValue().compareTo(o1.getValue()); 064 } 065 } 066 }); 067 return entries; 068 } 069 070 /** 071 * Constructs a multimap with the same mappings as the specified map. 072 * 073 * @param input the input map 074 * @return the multimap 075 */ 076 public static <K, V> Multimap<K, V> createMultiMap(Map<K, ? extends Iterable<V>> input) { 077 Multimap<K, V> multimap = ArrayListMultimap.create(); 078 for (Map.Entry<K, ? extends Iterable<V>> entry : input.entrySet()) { 079 multimap.putAll(entry.getKey(), entry.getValue()); 080 } 081 return multimap; 082 } 083 084 /** 085 * Creates a Guava sorted multimap using the input map. 086 * 087 * @param input the input map 088 * @return the multimap 089 */ 090 public static <K extends Comparable, V extends Comparable> Multimap<K, V> createSortedMultiMap(Map<K, ? extends Iterable<V>> input) { 091 Multimap<K, V> multimap = TreeMultimap.create(); 092 for (Map.Entry<K, ? extends Iterable<V>> entry : input.entrySet()) { 093 multimap.putAll(entry.getKey(), entry.getValue()); 094 } 095 return multimap; 096 } 097 098 /** 099 * Return map in TSV format. 100 * @param map the map 101 * @param <K> 102 * @param <V> 103 * @return TSV formatted String 104 */ 105 public static <K, V> String asTSV(Map<K, V> map) { 106 return Joiner.on("\n").withKeyValueSeparator("\t").join(map); 107 } 108 109 /** 110 * Return map in TSV format. 111 * @param map the map 112 * @param keyHeader header for key column 113 * @param valueHeader header for value column 114 * @param <K> 115 * @param <V> 116 * 117 * @return TSV formatted String 118 */ 119 public static <K, V> String asTSV(Map<K, V> map, String keyHeader, String valueHeader) { 120 return Strings.nullToEmpty(keyHeader) + "\t" + Strings.nullToEmpty(valueHeader) + "\n" + Joiner.on("\n").withKeyValueSeparator("\t").join(map); 121 } 122}