/*
* 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 com.hp.hpl.jena.tdb.base.page;
import org.openjena.atlas.logging.Log ;
import com.hp.hpl.jena.tdb.base.block.Block ;
import com.hp.hpl.jena.tdb.base.block.BlockConverter ;
import com.hp.hpl.jena.tdb.base.block.BlockMgr ;
import com.hp.hpl.jena.tdb.base.block.BlockType ;
/** Engine that wraps from blocks to typed pages. */
public class PageBlockMgr<T extends Page>
{
protected final BlockMgr blockMgr ;
protected BlockConverter<T> pageFactory ;
protected PageBlockMgr(BlockConverter<T> pageFactory, BlockMgr blockMgr)
{
this.pageFactory = pageFactory ;
this.blockMgr = blockMgr ;
}
// Sometimes, the subclass must pass null to the constructor then call this.
protected void setConverter(BlockConverter<T> pageFactory) { this.pageFactory = pageFactory ; }
public BlockMgr getBlockMgr() { return blockMgr ; }
// /** Allocate an uninitialized slot. Fill with a .put later */
// public int allocateId() { return blockMgr.allocateId() ; }
/** Allocate a new thing */
public T create(BlockType bType)
{
Block block = blockMgr.allocate(-1) ;
block.setModified(true) ;
T page = pageFactory.createFromBlock(block, bType) ;
return page ;
}
public T getWrite(int id)
{
Block block = blockMgr.getWrite(id) ;
block.setModified(true) ;
T page = pageFactory.fromBlock(block) ;
return page ;
}
public T getRead(int id)
{
Block block = blockMgr.getRead(id) ;
T page = pageFactory.fromBlock(block) ;
return page ;
}
public void put(T page)
{
write(page) ;
release(page) ;
}
public void write(T page)
{
// Catch updates to non-transactioned datasetgraph. Check in BlockMgrJournal instead.
// if ( ! page.getBackingBlock().isModified() )
// warn("Page for block "+page.getBackingBlock().getId()+" not modified") ;
Block blk = pageFactory.toBlock(page) ;
blockMgr.write(blk) ;
}
public void release(Page page)
{
Block block = page.getBackingBlock() ;
blockMgr.release(block) ;
}
private void warn(String string)
{
Log.warn(this, string) ;
}
public void free(Page page)
{
Block block = page.getBackingBlock() ;
blockMgr.free(block) ;
}
public void promote(Page page)
{
// Replace, reset Block in page.
Block block = page.getBackingBlock() ;
Block block2 = blockMgr.promote(block) ;
if ( block2 != block )
{
block2.setModified(true) ;
// Change - reset Block in page.
page.reset(block2) ;
}
}
public boolean valid(int id) { return blockMgr.valid(id) ; }
public void dump()
{
for ( int idx = 0 ; valid(idx) ; idx++ )
{
T page = getRead(idx) ;
System.out.println(page) ;
release(page) ;
}
}
/** Signal the start of an update operation */
public void startUpdate() { blockMgr.beginUpdate() ; }
/** Signal the completion of an update operation */
public void finishUpdate() { blockMgr.endUpdate() ; }
/** Signal the start of an update operation */
public void startRead() { blockMgr.beginRead() ; }
/** Signal the completeion of an update operation */
public void finishRead() { blockMgr.endRead() ; }
}