| /* |
| * 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 java.util.ArrayList; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| 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.exception.LdapException; |
| import org.apache.directory.api.ldap.model.filter.ExprNode; |
| import org.apache.directory.server.i18n.I18n; |
| import org.apache.directory.server.xdbm.AbstractIndexCursor; |
| import org.apache.directory.server.xdbm.IndexEntry; |
| import org.apache.directory.server.xdbm.search.Evaluator; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| |
| /** |
| * A Cursor returning candidates satisfying a logical disjunction expression. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public class OrCursor<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 static final String UNSUPPORTED_MSG = I18n.err( I18n.ERR_722 ); |
| private final List<Cursor<IndexEntry<V, String>>> cursors; |
| private final List<Evaluator<? extends ExprNode>> evaluators; |
| private final List<Set<String>> blacklists; |
| private int cursorIndex = -1; |
| |
| /** The candidate we have fetched in the next/previous call */ |
| private IndexEntry<V, String> prefetched; |
| |
| |
| // TODO - do same evaluator fail fast optimization that we do in AndCursor |
| public OrCursor( List<Cursor<IndexEntry<V, String>>> cursors, |
| List<Evaluator<? extends ExprNode>> evaluators ) |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Creating OrCursor {}", this ); |
| } |
| |
| if ( cursors.size() <= 1 ) |
| { |
| throw new IllegalArgumentException( I18n.err( I18n.ERR_723 ) ); |
| } |
| |
| this.cursors = cursors; |
| this.evaluators = evaluators; |
| this.blacklists = new ArrayList<Set<String>>(); |
| |
| for ( int i = 0; i < cursors.size(); i++ ) |
| { |
| this.blacklists.add( new HashSet<String>() ); |
| } |
| |
| this.cursorIndex = 0; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| protected String getUnsupportedMessage() |
| { |
| return UNSUPPORTED_MSG; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void beforeFirst() throws LdapException, CursorException |
| { |
| checkNotClosed( "beforeFirst()" ); |
| cursorIndex = 0; |
| cursors.get( cursorIndex ).beforeFirst(); |
| setAvailable( false ); |
| prefetched = null; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void afterLast() throws LdapException, CursorException |
| { |
| checkNotClosed( "afterLast()" ); |
| cursorIndex = cursors.size() - 1; |
| cursors.get( cursorIndex ).afterLast(); |
| setAvailable( false ); |
| prefetched = null; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean first() throws LdapException, CursorException |
| { |
| beforeFirst(); |
| |
| return setAvailable( next() ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean last() throws LdapException, CursorException |
| { |
| afterLast(); |
| |
| return setAvailable( previous() ); |
| } |
| |
| |
| private boolean isBlackListed( String id ) |
| { |
| return blacklists.get( cursorIndex ).contains( id ); |
| } |
| |
| |
| /** |
| * The first sub-expression Cursor to advance to an entry adds the entry |
| * to the blacklists of other Cursors that might return that entry. |
| * |
| * @param indexEntry the index entry to blacklist |
| * @throws Exception if there are problems accessing underlying db |
| */ |
| private void blackListIfDuplicate( IndexEntry<?, String> indexEntry ) throws LdapException |
| { |
| for ( int ii = 0; ii < evaluators.size(); ii++ ) |
| { |
| if ( ii == cursorIndex ) |
| { |
| continue; |
| } |
| |
| if ( evaluators.get( ii ).evaluate( indexEntry ) ) |
| { |
| blacklists.get( ii ).add( indexEntry.getId() ); |
| } |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean previous() throws LdapException, CursorException |
| { |
| while ( cursors.get( cursorIndex ).previous() ) |
| { |
| checkNotClosed( "previous()" ); |
| IndexEntry<V, String> candidate = cursors.get( cursorIndex ).get(); |
| |
| if ( !isBlackListed( candidate.getId() ) ) |
| { |
| blackListIfDuplicate( candidate ); |
| |
| prefetched = candidate; |
| return setAvailable( true ); |
| } |
| } |
| |
| while ( cursorIndex > 0 ) |
| { |
| checkNotClosed( "previous()" ); |
| cursorIndex--; |
| cursors.get( cursorIndex ).afterLast(); |
| |
| while ( cursors.get( cursorIndex ).previous() ) |
| { |
| checkNotClosed( "previous()" ); |
| IndexEntry<V, String> candidate = cursors.get( cursorIndex ).get(); |
| |
| if ( !isBlackListed( candidate.getId() ) ) |
| { |
| blackListIfDuplicate( candidate ); |
| |
| prefetched = candidate; |
| return setAvailable( true ); |
| } |
| } |
| } |
| |
| prefetched = null; |
| |
| return setAvailable( false ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean next() throws LdapException, CursorException |
| { |
| while ( cursors.get( cursorIndex ).next() ) |
| { |
| checkNotClosed( "next()" ); |
| IndexEntry<V, String> candidate = cursors.get( cursorIndex ).get(); |
| |
| if ( !isBlackListed( candidate.getId() ) ) |
| { |
| blackListIfDuplicate( candidate ); |
| |
| prefetched = candidate; |
| |
| return setAvailable( true ); |
| } |
| } |
| |
| while ( cursorIndex < cursors.size() - 1 ) |
| { |
| checkNotClosed( "previous()" ); |
| cursorIndex++; |
| cursors.get( cursorIndex ).beforeFirst(); |
| |
| while ( cursors.get( cursorIndex ).next() ) |
| { |
| checkNotClosed( "previous()" ); |
| IndexEntry<V, String> candidate = cursors.get( cursorIndex ).get(); |
| |
| if ( !isBlackListed( candidate.getId() ) ) |
| { |
| blackListIfDuplicate( candidate ); |
| |
| prefetched = candidate; |
| |
| return setAvailable( true ); |
| } |
| } |
| } |
| |
| prefetched = null; |
| |
| return setAvailable( false ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public IndexEntry<V, String> get() throws CursorException |
| { |
| checkNotClosed( "get()" ); |
| |
| if ( available() ) |
| { |
| return prefetched; |
| } |
| |
| throw new InvalidCursorPositionException( I18n.err( I18n.ERR_708 ) ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close() |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing OrCursor {}", this ); |
| } |
| |
| super.close(); |
| |
| for ( Cursor<?> cursor : cursors ) |
| { |
| cursor.close(); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close( Exception cause ) |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing OrCursor {}", this ); |
| } |
| |
| super.close( cause ); |
| |
| for ( Cursor<?> cursor : cursors ) |
| { |
| cursor.close( cause ); |
| } |
| } |
| |
| |
| /** |
| * Dumps the evaluators |
| */ |
| private String dumpEvaluators( String tabs ) |
| { |
| StringBuilder sb = new StringBuilder(); |
| |
| for ( Evaluator<? extends ExprNode> evaluator : evaluators ) |
| { |
| sb.append( evaluator.toString( tabs + " >>" ) ); |
| } |
| |
| return sb.toString(); |
| } |
| |
| |
| /** |
| * Dumps the cursors |
| */ |
| private String dumpCursors( String tabs ) |
| { |
| StringBuilder sb = new StringBuilder(); |
| |
| for ( Cursor<IndexEntry<V, String>> cursor : cursors ) |
| { |
| sb.append( cursor.toString( tabs + " " ) ); |
| sb.append( "\n" ); |
| } |
| |
| return sb.toString(); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| public String toString( String tabs ) |
| { |
| StringBuilder sb = new StringBuilder(); |
| |
| sb.append( tabs ).append( "OrCursor (" ); |
| |
| if ( available() ) |
| { |
| sb.append( "available)" ); |
| } |
| else |
| { |
| sb.append( "absent)" ); |
| } |
| |
| sb.append( "#" ).append( cursorIndex ).append( " : \n" ); |
| |
| if ( ( evaluators != null ) && ( evaluators.size() > 0 ) ) |
| { |
| sb.append( dumpEvaluators( tabs ) ); |
| } |
| |
| if ( ( cursors != null ) && ( cursors.size() > 0 ) ) |
| { |
| sb.append( dumpCursors( tabs ) ).append( '\n' ); |
| } |
| |
| return sb.toString(); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| public String toString() |
| { |
| return toString( "" ); |
| } |
| } |