/*
Derby - Class org.apache.derby.impl.store.access.btree.index.B2IMaxScan
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.derby.impl.store.access.btree.index;
import org.apache.derby.iapi.services.sanity.SanityManager;
import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.iapi.store.access.conglomerate.TransactionManager;
import org.apache.derby.iapi.store.access.ConglomerateController;
import org.apache.derby.iapi.store.access.DynamicCompiledOpenConglomInfo;
import org.apache.derby.iapi.store.access.Qualifier;
import org.apache.derby.iapi.store.access.ScanController;
import org.apache.derby.iapi.store.access.StaticCompiledOpenConglomInfo;
import org.apache.derby.iapi.store.access.TransactionController;
import org.apache.derby.iapi.store.raw.LockingPolicy;
import org.apache.derby.iapi.store.raw.Transaction;
import org.apache.derby.iapi.types.DataValueDescriptor;
import org.apache.derby.iapi.services.io.FormatableBitSet;
import org.apache.derby.impl.store.access.btree.BTreeLockingPolicy;
import org.apache.derby.impl.store.access.btree.BTreeMaxScan;
// For JavaDoc references (i.e. @see)
import org.apache.derby.iapi.store.access.GenericScanController;
/**
Scan used to find maximum value in the secondary index.
This class implements an optimized interface to find the maximum row,
for a set of rows between an input start and stop key.
Note most work of this class is inherited from the generic btree implementation.
This class initializes the top level object and deals with locking information
specific to a secondary index implementation of a btree.
**/
public class B2IMaxScan extends BTreeMaxScan
{
/*
** Fields of B2IMaxScan.
*/
private ConglomerateController base_cc_for_locking;
/*
** Methods of B2IMaxScan.
*/
B2IMaxScan()
{
// Perform the generic b-tree scan construction.
super();
}
/**
Close the scan.
@see GenericScanController#newRowLocationTemplate
**/
public void close()
throws StandardException
{
super.close();
if (base_cc_for_locking != null)
{
base_cc_for_locking.close();
base_cc_for_locking = null;
}
}
/**
Close the scan, a commit or abort is about to happen.
**/
public boolean closeForEndTransaction(boolean closeHeldScan)
throws StandardException
{
boolean ret_val = super.closeForEndTransaction(closeHeldScan);
if (SanityManager.DEBUG)
SanityManager.ASSERT(
ret_val, "B2IMaxScan never should be held across a commit.");
if (base_cc_for_locking != null)
{
base_cc_for_locking.close();
base_cc_for_locking = null;
}
return(ret_val);
}
/**
Initialize the scan for use.
<p>
Any changes to this method may have to be reflected in close as well.
<p>
The btree init opens the container (super.init), and stores away the
state of the qualifiers. The actual searching for the first position
is delayed until the first next() call.
@exception StandardException Standard exception policy.
**/
public void init(
TransactionManager xact_manager,
Transaction rawtran,
int open_mode,
int lock_level,
LockingPolicy locking_policy,
int isolation_level,
boolean open_for_locking,
FormatableBitSet scanColumnList,
B2I conglomerate,
B2IUndo undo)
throws StandardException
{
// open and lock the base table.
int base_open_mode =
open_mode | TransactionController.OPENMODE_FOR_LOCK_ONLY;
// open the base conglomerate - just to get lock
base_cc_for_locking =
xact_manager.openConglomerate(
conglomerate.baseConglomerateId, false,
base_open_mode, lock_level,
isolation_level);
BTreeLockingPolicy b2i_locking_policy =
conglomerate.getBtreeLockingPolicy(
rawtran, lock_level, open_mode, isolation_level,
base_cc_for_locking, this);
super.init(
xact_manager,
rawtran,
false,
open_mode,
lock_level,
b2i_locking_policy,
scanColumnList,
(DataValueDescriptor[]) null,// no start position supported
ScanController.NA, // no start position supported
(Qualifier[][]) null, // no qualifier supported
(DataValueDescriptor[]) null,// no stop position supported
ScanController.NA, // no stop position supported
conglomerate,
undo,
(StaticCompiledOpenConglomInfo) null,
(DynamicCompiledOpenConglomInfo) null);
}
}