/*
* 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.impl;
import org.apache.directory.server.xdbm.IndexEntry;
import org.apache.directory.server.xdbm.Store;
import org.apache.directory.server.xdbm.AbstractIndexCursor;
import org.apache.directory.server.xdbm.IndexCursor;
import org.apache.directory.server.core.entry.ServerEntry;
import org.apache.directory.server.i18n.I18n;
import org.apache.directory.shared.ldap.cursor.InvalidCursorPositionException;
import org.apache.directory.shared.ldap.schema.AttributeType;
/**
* A returning candidates satisfying an attribute presence expression.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $$Rev$$
*/
public class PresenceCursor<ID> extends AbstractIndexCursor<String, ServerEntry, ID>
{
private static final String UNSUPPORTED_MSG = I18n.err( I18n.ERR_724 );
private final IndexCursor<String, ServerEntry, ID> ndnCursor;
private final IndexCursor<String, ServerEntry, ID> presenceCursor;
private final PresenceEvaluator<ID> presenceEvaluator;
private boolean available = false;
public PresenceCursor( Store<ServerEntry, ID> db, PresenceEvaluator<ID> presenceEvaluator ) throws Exception
{
this.presenceEvaluator = presenceEvaluator;
AttributeType type = presenceEvaluator.getAttributeType();
// we don't maintain a presence index for objectClass, entryUUID, and entryCSN
// as it doesn't make sense because every entry has such an attribute
// instead for those attributes and all un-indexed attributes we use the ndn index
if ( db.hasUserIndexOn( type.getOid() ) )
{
presenceCursor = db.getPresenceIndex().forwardCursor( type.getOid() );
ndnCursor = null;
}
else
{
presenceCursor = null;
ndnCursor = db.getNdnIndex().forwardCursor();
}
}
public boolean available()
{
if ( presenceCursor != null )
{
return presenceCursor.available();
}
return available;
}
public void beforeValue( ID id, String value ) throws Exception
{
checkNotClosed( "beforeValue()" );
if ( presenceCursor != null )
{
presenceCursor.beforeValue( id, value );
return;
}
throw new UnsupportedOperationException( UNSUPPORTED_MSG );
}
public void before( IndexEntry<String, ServerEntry, ID> element ) throws Exception
{
checkNotClosed( "before()" );
if ( presenceCursor != null )
{
presenceCursor.before( element );
return;
}
throw new UnsupportedOperationException( UNSUPPORTED_MSG );
}
public void afterValue( ID id, String value ) throws Exception
{
checkNotClosed( "afterValue()" );
if ( presenceCursor != null )
{
presenceCursor.afterValue( id, value );
return;
}
throw new UnsupportedOperationException( UNSUPPORTED_MSG );
}
public void after( IndexEntry<String, ServerEntry, ID> element ) throws Exception
{
checkNotClosed( "after()" );
if ( presenceCursor != null )
{
presenceCursor.after( element );
return;
}
throw new UnsupportedOperationException( UNSUPPORTED_MSG );
}
public void beforeFirst() throws Exception
{
checkNotClosed( "beforeFirst()" );
if ( presenceCursor != null )
{
presenceCursor.beforeFirst();
return;
}
ndnCursor.beforeFirst();
available = false;
}
public void afterLast() throws Exception
{
checkNotClosed( "afterLast()" );
if ( presenceCursor != null )
{
presenceCursor.afterLast();
return;
}
ndnCursor.afterLast();
available = false;
}
public boolean first() throws Exception
{
checkNotClosed( "first()" );
if ( presenceCursor != null )
{
return presenceCursor.first();
}
beforeFirst();
return next();
}
public boolean last() throws Exception
{
checkNotClosed( "last()" );
if ( presenceCursor != null )
{
return presenceCursor.last();
}
afterLast();
return previous();
}
public boolean previous() throws Exception
{
checkNotClosed( "previous()" );
if ( presenceCursor != null )
{
return presenceCursor.previous();
}
while ( ndnCursor.previous() )
{
checkNotClosed( "previous()" );
IndexEntry<?, ServerEntry, ID> candidate = ndnCursor.get();
if ( presenceEvaluator.evaluate( candidate ) )
{
return available = true;
}
}
return available = false;
}
public boolean next() throws Exception
{
checkNotClosed( "next()" );
if ( presenceCursor != null )
{
return presenceCursor.next();
}
while ( ndnCursor.next() )
{
checkNotClosed( "next()" );
IndexEntry<?, ServerEntry, ID> candidate = ndnCursor.get();
if ( presenceEvaluator.evaluate( candidate ) )
{
return available = true;
}
}
return available = false;
}
public IndexEntry<String, ServerEntry, ID> get() throws Exception
{
checkNotClosed( "get()" );
if ( presenceCursor != null )
{
if ( presenceCursor.available() )
{
return presenceCursor.get();
}
throw new InvalidCursorPositionException( I18n.err( I18n.ERR_708 ) );
}
if ( available )
{
/*
* The value of NDN indices is the normalized dn and we want the
* value to be the value of the attribute in question. So we will
* set that accordingly here.
*/
IndexEntry<String, ServerEntry, ID> indexEntry = ndnCursor.get();
indexEntry.setValue( presenceEvaluator.getAttributeType().getOid() );
return indexEntry;
}
throw new InvalidCursorPositionException( I18n.err( I18n.ERR_708 ) );
}
public boolean isElementReused()
{
if ( presenceCursor != null )
{
return presenceCursor.isElementReused();
}
return ndnCursor.isElementReused();
}
public void close() throws Exception
{
super.close();
if ( presenceCursor != null )
{
presenceCursor.close();
}
else
{
ndnCursor.close();
}
}
}