Java tutorial
//package com.java2s; /* * JPPF. * Copyright (C) 2005-2010 JPPF Team. * http://www.jppf.org * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.util.*; public class Main { /** * Remove an element from a map whose values are lists of elements. * @param <T> the type of the keys in the map. * @param <U> the type of the elements in the lists. * @param key the key for the value to remove. * @param value the value to remove. * @param map the map from which to remove the key/value pair. */ public static <T, U> void removeFromListMap(T key, U value, Map<T, List<U>> map) { List<U> list = map.get(key); if (list == null) return; list.remove(value); if (list.isEmpty()) map.remove(key); } }