Multi Value Map Array List : Map « Collections Data Structure « Java






  1. Java
  2. Collections Data Structure
  3. Map

Multi Value Map Array List

/* * Copyright WizTools.org * Licensed under the Apache License, Version 2.0: * http://www.apache.org/licenses/LICENSE-2.0 *///package org.wiztools.commons; import java.util.ArrayList; import java.util.Collection; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Set; /** * This class does not implement java.util.Map&lt;K, V&gt; interface. * This class encapsulates a HashMap holding a List of values associated with a * particular key. * @author subwiz */publicclass MultiValueMapArrayList<K, V> implements MultiValueMap<K, V>{ private Map<K, List<V>> map = new LinkedHashMap<K, List<V>>(); public Collection<V> put(K key, V value){ List<V> l = map.get(key); if(l == null){ l = new ArrayList<V>(); } l.add(value); return map.put(key, l); } public Collection<V> get(K key){ return map.get(key); } public Set<K> keySet(){ return map.keySet(); } publicint size() { return map.size(); } publicboolean isEmpty() { if(size() == 0) return true; return false; } publicboolean containsKey(K key) { return map.containsKey(key); } publicboolean containsValue(V value) { for(K key: map.keySet()){ List<V> values = map.get(key); if(values.contains(value)){ return true; } } return false; } public Collection<V> remove(K key) { return map.remove(key); } publicvoid clear() { map.clear(); } public Collection<V> values() { List<V> values = new ArrayList<V>(); for(K key: map.keySet()){ List<V> v = map.get(key); values.addAll(v); } return values; } @Override publicboolean equals(Object obj) { if (obj == null) { return false; } if (!(obj instanceof MultiValueMap)) { return false; } final MultiValueMap<K, V> other = (MultiValueMap<K, V>) obj; if (this.keySet() != other.keySet() && (this.keySet() == null || !this.keySet().equals(other.keySet()))) { return false; } final Collection thisValues = this.values(); final Collection otherValues = other.values(); if (thisValues != otherValues && (thisValues == null || !thisValues.equals(otherValues))) { return false; } return true; } @Override publicint hashCode() { int hash = 7; hash = 47 * hash + (this.map != null ? this.map.hashCode() : 0); return hash; } @Override public String toString() { return map.toString(); } } interface MultiValueMap<K, V> { void clear(); boolean containsKey(K key); boolean containsValue(V value); Collection<V> get(K key); boolean isEmpty(); Set<K> keySet(); Collection<V> put(K key, V value); Collection<V> remove(K key); int size(); Collection<V> values(); }








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