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 package org.apache.directory.api.ldap.model.schema.comparators; 21 22 23 import java.io.Serializable; 24 25 import org.apache.directory.api.ldap.model.schema.LdapComparator; 26 import org.slf4j.Logger; 27 import org.slf4j.LoggerFactory; 28 29 30 /** 31 * A comparator for Strings. 32 * 33 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 34 */ 35 public class StringComparator extends LdapComparator<String> implements Serializable 36 { 37 /** The serial version UID */ 38 private static final long serialVersionUID = 2L; 39 40 /** A logger for this class */ 41 private static final Logger LOG = LoggerFactory.getLogger( StringComparator.class ); 42 43 44 /** 45 * The StringComparator constructor. Its OID is the StringMatch matching 46 * rule OID. 47 */ 48 public StringComparator( String oid ) 49 { 50 super( oid ); 51 } 52 53 54 /** 55 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object) 56 */ 57 @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "ES_COMPARING_PARAMETER_STRING_WITH_EQ", 58 justification = "false positive") 59 public int compare( String s1, String s2 ) 60 { 61 LOG.debug( "comparing String objects '{}' with '{}'", s1, s2 ); 62 63 if ( s1 == s2 ) 64 { 65 return 0; 66 } 67 68 // ------------------------------------------------------------------- 69 // Handle some basis cases 70 // ------------------------------------------------------------------- 71 if ( s1 == null ) 72 { 73 return ( s2 == null ) ? 0 : -1; 74 } 75 76 if ( s2 == null ) 77 { 78 return 1; 79 } 80 81 return s1.compareTo( s2 ); 82 } 83 }