| /* |
| * 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.entry.Value; |
| import org.apache.directory.api.ldap.model.exception.LdapException; |
| import org.apache.directory.api.ldap.model.schema.AttributeType; |
| 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.ApproximateEvaluator; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| |
| /** |
| * A Cursor over entry candidates matching an approximate assertion filter. |
| * This Cursor really is a copy of EqualityCursor for now but later on |
| * approximate matching can be implemented and this can change. It operates |
| * in two modes. The first is when an index exists for the attribute the |
| * approximate assertion is built on. The second is when the user index for |
| * the assertion attribute does not exist. Different Cursors are used in each |
| * of these cases where the other remains null. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public class ApproximateCursor<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(); |
| |
| /** The message for unsupported operations */ |
| private static final String UNSUPPORTED_MSG = "ApproximateCursors only support positioning by element when a user index exists on the asserted attribute."; |
| |
| /** An approximate evaluator for candidates */ |
| private final ApproximateEvaluator<V> approximateEvaluator; |
| |
| /** Cursor over attribute entry matching filter: set when index present */ |
| private final Cursor<IndexEntry<V, String>> userIdxCursor; |
| |
| /** NDN Cursor on all entries in (set when no index on user attribute) */ |
| private final Cursor<IndexEntry<String, String>> uuidIdxCursor; |
| |
| |
| /** |
| * Creates a new instance of ApproximateCursor |
| * @param store The Store we want to build a cursor on |
| * @param approximateEvaluator The evaluator |
| * @throws Exception If the creation failed |
| */ |
| @SuppressWarnings("unchecked") |
| public ApproximateCursor( Store store, ApproximateEvaluator<V> approximateEvaluator ) throws Exception |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Creating ApproximateCursor {}", this ); |
| } |
| |
| this.approximateEvaluator = approximateEvaluator; |
| |
| AttributeType attributeType = approximateEvaluator.getExpression().getAttributeType(); |
| Value<V> value = approximateEvaluator.getExpression().getValue(); |
| |
| if ( store.hasIndexOn( attributeType ) ) |
| { |
| Index<V, String> index = ( Index<V, String> ) store.getIndex( attributeType ); |
| userIdxCursor = index.forwardCursor( value.getValue() ); |
| uuidIdxCursor = null; |
| } |
| else |
| { |
| uuidIdxCursor = new AllEntriesCursor( store ); |
| userIdxCursor = null; |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| protected String getUnsupportedMessage() |
| { |
| return UNSUPPORTED_MSG; |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean available() |
| { |
| if ( userIdxCursor != null ) |
| { |
| return userIdxCursor.available(); |
| } |
| |
| return super.available(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void before( IndexEntry<V, String> element ) throws LdapException, CursorException |
| { |
| checkNotClosed( "before()" ); |
| |
| if ( userIdxCursor != null ) |
| { |
| userIdxCursor.before( element ); |
| } |
| else |
| { |
| super.before( element ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void after( IndexEntry<V, String> element ) throws LdapException, CursorException |
| { |
| checkNotClosed( "after()" ); |
| |
| if ( userIdxCursor != null ) |
| { |
| userIdxCursor.after( element ); |
| } |
| else |
| { |
| super.after( element ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void beforeFirst() throws LdapException, CursorException |
| { |
| checkNotClosed( "beforeFirst()" ); |
| if ( userIdxCursor != null ) |
| { |
| userIdxCursor.beforeFirst(); |
| } |
| else |
| { |
| uuidIdxCursor.beforeFirst(); |
| setAvailable( false ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void afterLast() throws LdapException, CursorException |
| { |
| checkNotClosed( "afterLast()" ); |
| |
| if ( userIdxCursor != null ) |
| { |
| userIdxCursor.afterLast(); |
| } |
| else |
| { |
| uuidIdxCursor.afterLast(); |
| setAvailable( false ); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean first() throws LdapException, CursorException |
| { |
| beforeFirst(); |
| |
| return next(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean last() throws LdapException, CursorException |
| { |
| afterLast(); |
| |
| return previous(); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean previous() throws LdapException, CursorException |
| { |
| if ( userIdxCursor != null ) |
| { |
| return userIdxCursor.previous(); |
| } |
| |
| while ( uuidIdxCursor.previous() ) |
| { |
| checkNotClosed( "previous()" ); |
| IndexEntry<?, String> candidate = uuidIdxCursor.get(); |
| |
| if ( approximateEvaluator.evaluate( candidate ) ) |
| { |
| return setAvailable( true ); |
| } |
| } |
| |
| return setAvailable( false ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public boolean next() throws LdapException, CursorException |
| { |
| if ( userIdxCursor != null ) |
| { |
| return userIdxCursor.next(); |
| } |
| |
| while ( uuidIdxCursor.next() ) |
| { |
| checkNotClosed( "next()" ); |
| IndexEntry<?, String> candidate = uuidIdxCursor.get(); |
| |
| if ( approximateEvaluator.evaluate( candidate ) ) |
| { |
| return setAvailable( true ); |
| } |
| } |
| |
| return setAvailable( false ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @SuppressWarnings("unchecked") |
| public IndexEntry<V, String> get() throws CursorException |
| { |
| checkNotClosed( "get()" ); |
| |
| if ( userIdxCursor != null ) |
| { |
| return userIdxCursor.get(); |
| } |
| |
| if ( available() ) |
| { |
| return ( IndexEntry<V, String> ) uuidIdxCursor.get(); |
| } |
| |
| throw new InvalidCursorPositionException( I18n.err( I18n.ERR_708 ) ); |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close() |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing ApproximateCursor {}", this ); |
| } |
| |
| super.close(); |
| |
| if ( userIdxCursor != null ) |
| { |
| userIdxCursor.close(); |
| } |
| else |
| { |
| uuidIdxCursor.close(); |
| } |
| } |
| |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public void close( Exception cause ) |
| { |
| if ( IS_DEBUG ) |
| { |
| LOG_CURSOR.debug( "Closing ApproximateCursor {}", this ); |
| } |
| |
| super.close( cause ); |
| |
| if ( userIdxCursor != null ) |
| { |
| userIdxCursor.close( cause ); |
| } |
| else |
| { |
| uuidIdxCursor.close( cause ); |
| } |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| public String toString( String tabs ) |
| { |
| StringBuilder sb = new StringBuilder(); |
| |
| sb.append( tabs ).append( "ApproximateCursor (" ); |
| |
| if ( available() ) |
| { |
| sb.append( "available)" ); |
| } |
| else |
| { |
| sb.append( "absent)" ); |
| } |
| |
| sb.append( " :\n" ); |
| |
| sb.append( tabs + " >>" ).append( approximateEvaluator ).append( '\n' ); |
| |
| if ( userIdxCursor != null ) |
| { |
| sb.append( tabs + " <user>\n" ); |
| sb.append( userIdxCursor.toString( tabs + " " ) ); |
| } |
| |
| if ( uuidIdxCursor != null ) |
| { |
| sb.append( tabs + " <uuid>\n" ); |
| sb.append( uuidIdxCursor.toString( tabs + " " ) ); |
| } |
| |
| return sb.toString(); |
| } |
| |
| |
| /** |
| * @see Object#toString() |
| */ |
| public String toString() |
| { |
| return toString( "" ); |
| } |
| } |