Multi Value Map Linked HashSet : Map « Collections Data Structure « Java

Multi Value Map Linked HashSet

 * Copyright
 * Licensed under the Apache License, Version 2.0:
//package org.wiztools.commons;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

 * @author subwiz
public class MultiValueMapLinkedHashSet<K, V> implements MultiValueMap<K, V> {
    private Map<K, Set<V>> map = new LinkedHashMap<K, Set<V>>();

    public Collection<V> put(K key, V value){
        Set<V> l = map.get(key);
        if(l == null){
            l = new LinkedHashSet<V>();
        return map.put(key, l);

    public Collection<V> get(K key){
        return map.get(key);

    public Set<K> keySet(){
        return map.keySet();

    public int size() {
        return map.size();

    public boolean isEmpty() {
        if(size() == 0)
            return true;
        return false;

    public boolean containsKey(K key) {
        return map.containsKey(key);

    public boolean containsValue(V value) {
        for(K key: map.keySet()){
            Set<V> values = map.get(key);
                return true;
        return false;

    public Collection<V> remove(K key) {
        return map.remove(key);

    public void clear() {

    public Collection<V> values() {
        List<V> values = new ArrayList<V>();
        for(K key: map.keySet()){
            Set<V> v = map.get(key);
        return values;

    public boolean 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;
        if (this.values() != other.values() && (this.values() == null || !this.values().equals(other.values()))) {
            return false;
        return true;

    public int hashCode() {
        int hash = 5;
        hash = 71 * hash + ( != null ? : 0);
        return hash;

    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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