| /* |
| * 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.search.cursor; |
| |
| |
| import org.apache.directory.api.ldap.model.constants.Loggers; |
| import org.apache.directory.api.ldap.model.cursor.Cursor; |
| 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.entry.Entry; |
| import org.apache.directory.api.ldap.model.exception.LdapException; |
| import org.apache.directory.server.i18n.I18n; |
| import org.apache.directory.server.xdbm.AbstractIndexCursor; |
| import org.apache.directory.server.xdbm.Index; |
| import org.apache.directory.server.xdbm.IndexEntry; |
| import org.apache.directory.server.xdbm.Store; |
| import org.apache.directory.server.xdbm.search.evaluator.SubstringEvaluator; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| |
| /** |
| * A Cursor traversing candidates matching a Substring assertion expression. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public class SubstringCursor extends AbstractIndexCursor<String> |
| { |
| /** 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 static final String UNSUPPORTED_MSG = I18n.err( I18n.ERR_725 ); |
| private final boolean hasIndex; |
| private final Cursor<IndexEntry<String, String>> wrapped; |
| private final SubstringEvaluator evaluator; |
| private final IndexEntry<String, String> indexEntry = new IndexEntry<String, String>(); |
| |
| |
| @SuppressWarnings("unchecked") |
| public SubstringCursor( Store store, final SubstringEvaluator substringEvaluator ) |
| throws Exception |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Creating SubstringCursor {}", this ); |
| } |
| |
| evaluator = substringEvaluator; |
| hasIndex = store.hasIndexOn( evaluator.getExpression().getAttributeType() ); |
| |
| if ( hasIndex ) |
| { |
| wrapped = ( ( Index<String, String> ) store.getIndex( evaluator.getExpression().getAttributeType() ) ) |
| .forwardCursor(); |
| } |
| else |
| { |
| /* |
| * There is no index on the attribute here. We have no choice but |
| * to perform a full table scan but need to leverage an index for the |
| * wrapped Cursor. We know that all entries are listed under |
| * the ndn index and so this will enumerate over all entries. The |
| * substringEvaluator is used in an assertion to constrain the |
| * result set to only those entries matching the pattern. The |
| * substringEvaluator handles all the details of normalization and |
| * knows to use it, when it itself detects the lack of an index on |
| * the node's attribute. |
| */ |
| wrapped = new AllEntriesCursor( store ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| protected String getUnsupportedMessage() |
| { |
| return UNSUPPORTED_MSG; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void beforeFirst() throws LdapException, CursorException |
| { |
| checkNotClosed( "beforeFirst()" ); |
| if ( evaluator.getExpression().getInitial() != null && hasIndex ) |
| { |
| IndexEntry<String, String> indexEntry = new IndexEntry<String, String>(); |
| indexEntry.setKey( evaluator.getExpression().getInitial() ); |
| wrapped.before( indexEntry ); |
| } |
| else |
| { |
| wrapped.beforeFirst(); |
| } |
| |
| clear(); |
| } |
| |
| |
| private void clear() |
| { |
| setAvailable( false ); |
| indexEntry.setEntry( null ); |
| indexEntry.setId( null ); |
| indexEntry.setKey( null ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void afterLast() throws LdapException, CursorException |
| { |
| checkNotClosed( "afterLast()" ); |
| |
| // to keep the cursor always *after* the last matched tuple |
| // This fixes an issue if the last matched tuple is also the last record present in the |
| // index. In this case the wrapped cursor is positioning on the last tuple instead of positioning after that |
| wrapped.afterLast(); |
| clear(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean first() throws LdapException, CursorException |
| { |
| beforeFirst(); |
| return next(); |
| } |
| |
| |
| private boolean evaluateCandidate( IndexEntry<String, String> indexEntry ) throws LdapException |
| { |
| if ( hasIndex ) |
| { |
| String key = indexEntry.getKey(); |
| return evaluator.getPattern().matcher( key ).matches(); |
| } |
| else |
| { |
| return evaluator.evaluate( indexEntry ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean last() throws LdapException, CursorException |
| { |
| afterLast(); |
| |
| return previous(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean previous() throws LdapException, CursorException |
| { |
| while ( wrapped.previous() ) |
| { |
| checkNotClosed( "previous()" ); |
| IndexEntry<String, String> entry = wrapped.get(); |
| |
| if ( evaluateCandidate( entry ) ) |
| { |
| setAvailable( true ); |
| this.indexEntry.setId( entry.getId() ); |
| this.indexEntry.setKey( entry.getKey() ); |
| this.indexEntry.setEntry( entry.getEntry() ); |
| return true; |
| } |
| } |
| |
| clear(); |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean next() throws LdapException, CursorException |
| { |
| while ( wrapped.next() ) |
| { |
| checkNotClosed( "next()" ); |
| IndexEntry<String, String> entry = wrapped.get(); |
| |
| if ( evaluateCandidate( entry ) ) |
| { |
| setAvailable( true ); |
| this.indexEntry.setId( entry.getId() ); |
| this.indexEntry.setKey( entry.getKey() ); |
| this.indexEntry.setEntry( entry.getEntry() ); |
| |
| return true; |
| } |
| } |
| |
| clear(); |
| return false; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public IndexEntry<String, String> get() throws CursorException |
| { |
| checkNotClosed( "get()" ); |
| |
| if ( available() ) |
| { |
| return indexEntry; |
| } |
| |
| throw new InvalidCursorPositionException( I18n.err( I18n.ERR_708 ) ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close() |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing SubstringCursor {}", this ); |
| } |
| |
| super.close(); |
| wrapped.close(); |
| clear(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close( Exception cause ) |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing SubstringCursor {}", this ); |
| } |
| |
| super.close( cause ); |
| wrapped.close( cause ); |
| clear(); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| public String toString( String tabs ) |
| { |
| StringBuilder sb = new StringBuilder(); |
| |
| sb.append( tabs ).append( "SubstringCursor (" ); |
| |
| if ( available() ) |
| { |
| sb.append( "available)" ); |
| } |
| else |
| { |
| sb.append( "absent)" ); |
| } |
| |
| sb.append( "#index<" ).append( hasIndex ).append( "> :\n" ); |
| |
| sb.append( tabs + " >>" ).append( evaluator ).append( '\n' ); |
| |
| sb.append( wrapped.toString( tabs + " " ) ); |
| |
| return sb.toString(); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| public String toString() |
| { |
| return toString( "" ); |
| } |
| } |