| /* |
| * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. |
| */ |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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. |
| */ |
| /* |
| * $Id: MultiHashtable.java,v 1.2.4.1 2005/09/05 11:18:51 pvedula Exp $ |
| */ |
| |
| package com.sun.org.apache.xalan.internal.xsltc.compiler.util; |
| |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * @author Jacek Ambroziak |
| * @author Santiago Pericas-Geertsen |
| * @param <K> |
| * @param <V> |
| */ |
| public final class MultiHashtable<K,V> { |
| static final long serialVersionUID = -6151608290510033572L; |
| |
| private final Map<K, Set<V>> map = new HashMap<>(); |
| private boolean modifiable = true; |
| |
| /** |
| * Associates the specified key with a set of values. If the map previously |
| * contained a mapping for the key, the value is added to the set. |
| * @param key key with which the specified value is to be associated |
| * @param value value to be added to a set that is associated with the specified key |
| * @return the set that is associated with the specified key. |
| * @throw UnsupportedOperationException is the MultiHashtable is not modifiable. |
| */ |
| public Set<V> put(K key, V value) { |
| if (modifiable) { |
| Set<V> set = map.get(key); |
| if (set == null) { |
| set = new HashSet<>(); |
| map.put(key, set); |
| } |
| set.add(value); |
| return set; |
| } |
| throw new UnsupportedOperationException("The MultiHashtable instance is not modifiable."); |
| } |
| |
| /** |
| * Maps a key to a value in a set that is associated with the specified key. |
| * The mapping is performed by evaluating whether an item in the set equals |
| * the specified value. |
| * |
| * @param key key with which the specified value is to be associated |
| * @param value value in a set that is associated with the specified key |
| * @return the item in the set if a match is found. |
| */ |
| public V maps(K key, V value) { |
| if (key == null) return null; |
| final Set<V> set = map.get(key); |
| if (set != null) { |
| for (V v : set) { |
| if (v.equals(value)) { |
| return v; |
| } |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Makes the MultiHashtable unmodifiable. This method allows modules to set the table |
| * as "read-only" so that only query operation, that is maps, is allowed. Any attempts |
| * to modify the returned map result in an UnsupportedOperationException. |
| */ |
| public void makeUnmodifiable() { |
| modifiable = false; |
| } |
| } |