MultiMap.java

package com.hdweiss.morgand.utils;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;

public class MultiMap<T> {

	private HashMap<Long, ArrayList<T>> entryMap = new HashMap<Long, ArrayList<T>>();

	public void put(Long key, T value) {	
		ArrayList<T> valueList = entryMap.get(key);
		
		if(valueList == null) {
			valueList = new ArrayList<T>();
			entryMap.put(key, valueList);
		}
		
		valueList.add(value);
	}
	
	public ArrayList<T> get(Long key) {
		return entryMap.get(key);
	}

	public void remove(long key, T value) {
		ArrayList<T> valueList = entryMap.get(key);
		
		if(valueList != null) {
			valueList.remove(value);
		}
	}
	
	public Set<Long> keySet() {
		return entryMap.keySet();
	}
	
	public T findValue(long key, Object object) throws IllegalArgumentException {
		ArrayList<T> matches = entryMap.get(key);

		if (matches == null)
			return null;

		for (T match : matches) {
			if (match.equals(object))
				return match;
		}

		return null;
	}
}