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 021package org.apache.directory.server.core.partition.impl.btree.mavibot; 022 023 024import java.io.IOException; 025 026import org.apache.directory.api.ldap.model.cursor.AbstractCursor; 027import org.apache.directory.api.ldap.model.cursor.CursorException; 028import org.apache.directory.api.ldap.model.exception.LdapException; 029import org.apache.directory.mavibot.btree.ValueCursor; 030import org.apache.directory.server.i18n.I18n; 031 032 033/** 034 * TODO ValueTreeCursor. 035 * 036 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 037 */ 038public class ValueTreeCursor<V> extends AbstractCursor<V> 039{ 040 041 private ValueCursor<V> wrapped; 042 043 private V available; 044 045 // marker to detect the availability (cause Mavibot supports null values also) 046 private V notAvailable = ( V ) new Object(); 047 048 049 public ValueTreeCursor( ValueCursor<V> cursor ) 050 { 051 this.wrapped = cursor; 052 } 053 054 055 @Override 056 public boolean available() 057 { 058 return ( available != notAvailable ); 059 } 060 061 062 @Override 063 public void before( V element ) throws LdapException, CursorException 064 { 065 throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) ); 066 } 067 068 069 @Override 070 public void after( V element ) throws LdapException, CursorException 071 { 072 throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) ); 073 } 074 075 076 @Override 077 public void beforeFirst() throws LdapException, CursorException 078 { 079 } 080 081 082 @Override 083 public void afterLast() throws LdapException, CursorException 084 { 085 throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) ); 086 } 087 088 089 @Override 090 public boolean first() throws LdapException, CursorException 091 { 092 throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) ); 093 } 094 095 096 @Override 097 public boolean last() throws LdapException, CursorException 098 { 099 throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) ); 100 } 101 102 103 @Override 104 public boolean previous() throws LdapException, CursorException 105 { 106 try 107 { 108 if ( wrapped.hasPrev() ) 109 { 110 available = wrapped.prev(); 111 return true; 112 } 113 else 114 { 115 available = notAvailable; 116 return false; 117 } 118 } 119 catch ( IOException e ) 120 { 121 throw new CursorException( e ); 122 } 123 } 124 125 126 @Override 127 public boolean next() throws LdapException, CursorException 128 { 129 try 130 { 131 if ( wrapped.hasNext() ) 132 { 133 available = wrapped.next(); 134 return true; 135 } 136 else 137 { 138 available = notAvailable; 139 return false; 140 } 141 } 142 catch ( IOException e ) 143 { 144 throw new CursorException( e ); 145 } 146 } 147 148 149 @Override 150 public V get() throws CursorException 151 { 152 return available; 153 } 154 155}