001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020 021 package org.apache.directory.shared.ldap.util; 022 023 024 import java.util.HashMap; 025 026 import org.apache.directory.shared.i18n.I18n; 027 028 029 /** 030 * A Map implementation derived from HashMap that only overrides a single method 031 * put() in order to prevent duplicate keyed entries to be added. 032 * 033 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 034 * @version $Rev: 919765 $ 035 */ 036 public class NoDuplicateKeysMap extends HashMap 037 { 038 /** 039 * Overrides java.util.Map.put(java.lang.Object, java.lang.Object) to 040 * prevent duplicate keys. 041 * 042 * @see java.util.Map#put(java.lang.Object, java.lang.Object) 043 */ 044 public Object put( Object key, Object value ) throws IllegalArgumentException 045 { 046 if ( containsKey( key ) ) 047 { 048 throw new IllegalArgumentException( I18n.err( I18n.ERR_04422 ) ); 049 } 050 else 051 { 052 return super.put( key, value ); 053 } 054 } 055 056 // add a serial version uid, so that if we change things in the future 057 // without changing the format, we can still deserialize properly. 058 private static final long serialVersionUID = 5107433500719957457L; 059 }