MapList.java Source code

Introduction

Here is the source code for MapList.java

Source

//package org.streets.commons.collections;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

/**
 * Map from a given key to a list of values
 * 
 * @author dzb
 */
public class MapList<K, V> extends HashMap<K, List<V>> {

    private static final long serialVersionUID = 3462998132471897564L;

    public void add(K key, V value) {
        List<V> values = get(key);
        if (values == null) {
            values = new ArrayList<V>();
            put(key, values);
        }
        values.add(value);
    }

    public void remove(K key, V value) {
        List<V> values = get(key);
        if (values != null) {
            values.remove(value);
        }
    }

    public List<V> list(K key) {
        return super.get(key);
    }

    public V first(K key) {
        List<V> list = list(key);
        if (list != null && list.size() > 0) {
            return list.get(0);
        }
        return null;
    }
}