1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 * 19 */ 20 21 package org.apache.directory.api.util; 22 23 24 import java.util.HashMap; 25 26 import org.apache.directory.api.i18n.I18n; 27 28 29 /** 30 * A Map implementation derived from HashMap that only overrides a single method 31 * put() in order to prevent duplicate keyed entries to be added. 32 * 33 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 34 */ 35 @SuppressWarnings("rawtypes") 36 public class NoDuplicateKeysMap extends HashMap 37 { 38 /** 39 * Overrides java.util.Map.put(java.lang.Object, java.lang.Object) to 40 * prevent duplicate keys. 41 * 42 * @see java.util.Map#put(java.lang.Object, java.lang.Object) 43 */ 44 @SuppressWarnings("unchecked") 45 public Object put( Object key, Object value ) throws IllegalArgumentException 46 { 47 if ( containsKey( key ) ) 48 { 49 throw new IllegalArgumentException( I18n.err( I18n.ERR_04422 ) ); 50 } 51 else 52 { 53 return super.put( key, value ); 54 } 55 } 56 57 // add a serial version uid, so that if we change things in the future 58 // without changing the format, we can still deserialize properly. 59 private static final long serialVersionUID = 5107433500719957457L; 60 }