| /* |
| * 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. |
| */ |
| package org.apache.directory.server.xdbm; |
| |
| |
| import org.apache.directory.api.ldap.model.constants.Loggers; |
| import org.apache.directory.api.ldap.model.cursor.CursorException; |
| import org.apache.directory.api.ldap.model.cursor.InvalidCursorPositionException; |
| import org.apache.directory.api.ldap.model.exception.LdapException; |
| import org.apache.directory.server.i18n.I18n; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| |
| /** |
| * A Cursor over a single element. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public class SingletonIndexCursor<V> extends AbstractIndexCursor<V> |
| { |
| /** A dedicated log for cursors */ |
| private static final Logger LOG_CURSOR = LoggerFactory.getLogger( Loggers.CURSOR_LOG.getName() ); |
| |
| /** Speedup for logs */ |
| private static final boolean IS_DEBUG = LOG_CURSOR.isDebugEnabled(); |
| |
| private boolean beforeFirst = true; |
| private boolean afterLast; |
| private boolean onSingleton; |
| private final IndexEntry<V, String> singleton; |
| |
| |
| public SingletonIndexCursor( IndexEntry<V, String> singleton ) |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Creating SingletonIndexCursor {}", this ); |
| } |
| |
| this.singleton = singleton; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| protected String getUnsupportedMessage() |
| { |
| return UNSUPPORTED_MSG; |
| } |
| |
| |
| public boolean available() |
| { |
| return onSingleton; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void beforeFirst() throws LdapException, CursorException |
| { |
| checkNotClosed( "()" ); |
| beforeFirst = true; |
| afterLast = false; |
| onSingleton = false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void afterLast() throws LdapException, CursorException |
| { |
| checkNotClosed( "()" ); |
| beforeFirst = false; |
| afterLast = true; |
| onSingleton = false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean first() throws LdapException, CursorException |
| { |
| checkNotClosed( "()" ); |
| beforeFirst = false; |
| onSingleton = true; |
| afterLast = false; |
| return true; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean last() throws LdapException, CursorException |
| { |
| checkNotClosed( "()" ); |
| beforeFirst = false; |
| onSingleton = true; |
| afterLast = false; |
| return true; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean isFirst() |
| { |
| return onSingleton; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean isLast() |
| { |
| return onSingleton; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean isAfterLast() |
| { |
| return afterLast; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean isBeforeFirst() |
| { |
| return beforeFirst; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean previous() throws LdapException, CursorException |
| { |
| checkNotClosed( "()" ); |
| if ( beforeFirst ) |
| { |
| return false; |
| } |
| |
| if ( afterLast ) |
| { |
| beforeFirst = false; |
| onSingleton = true; |
| afterLast = false; |
| return true; |
| } |
| |
| // must be on the singleton |
| beforeFirst = true; |
| onSingleton = false; |
| afterLast = false; |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean next() throws LdapException, CursorException |
| { |
| checkNotClosed( "()" ); |
| if ( beforeFirst ) |
| { |
| beforeFirst = false; |
| onSingleton = true; |
| afterLast = false; |
| return true; |
| } |
| |
| if ( afterLast ) |
| { |
| return false; |
| } |
| |
| // must be on the singleton |
| beforeFirst = false; |
| onSingleton = false; |
| afterLast = true; |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public IndexEntry<V, String> get() throws CursorException |
| { |
| checkNotClosed( "()" ); |
| |
| if ( onSingleton ) |
| { |
| return singleton; |
| } |
| |
| if ( beforeFirst ) |
| { |
| throw new InvalidCursorPositionException( I18n.err( I18n.ERR_705 ) ); |
| } |
| else |
| { |
| throw new InvalidCursorPositionException( I18n.err( I18n.ERR_706 ) ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close() |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing SingletonIndexCursor {}", this ); |
| } |
| |
| super.close(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close( Exception cause ) |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing SingletonIndexCursor {}", this ); |
| } |
| |
| super.close( cause ); |
| } |
| } |