/*
* Copyright (C) 2006 http://www.chaidb.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
package org.chaidb.db.log.logrecord;
import org.apache.log4j.Logger;
import org.chaidb.db.exception.ChaiDBException;
import org.chaidb.db.exception.ErrorCode;
import org.chaidb.db.helper.ByteTool;
import org.chaidb.db.index.btree.BTreeSpec;
import org.chaidb.db.index.btree.bufmgr.PageBufferManager;
/**
* free page while BtreePage(or DataPage) add page to free list
* log the new allocated page number
*/
public class BTreeFreeOverflowPageLogRecord extends BTreeLogRecord {
private static final Logger logger = Logger.getLogger(BTreeFreeOverflowPageLogRecord.class);
private static PageBufferManager bpm = PageBufferManager.getInstance();
private short lowBound; //2 bytes
private short upperBound;//2bytes
private byte[] headArr; //lowBound bytes
private byte[] dataArr; //pageSize-upperBound size
private static final int LOWBOUND_SIZE = 2;//2 bytes
private static final int UPPERBOUND_SIZE = 2;//2 bytes
/**
* default Construct
*/
public BTreeFreeOverflowPageLogRecord() {
super();
super.setType(LOG_BTREE_FREE_OVERFLOWPAGE);
}
public BTreeFreeOverflowPageLogRecord(int treeId, int newPageNum, int newTxnId, byte[] headArr, byte[] dataArr, short btreeType) {
super(treeId, newPageNum, newTxnId, btreeType);
this.lowBound = (short) headArr.length;
this.upperBound = (short) (BTreeSpec.PAGE_SIZE - dataArr.length);
this.headArr = headArr;
this.dataArr = dataArr;
super.setType(LOG_BTREE_FREE_OVERFLOWPAGE);
}
public byte[] getDataArr() {
return ByteTool.copyByteArray(dataArr, 0, dataArr.length);
}
public byte[] getHeadArr() {
return ByteTool.copyByteArray(headArr, 0, headArr.length);
}
public short getUpperBound() {
return upperBound;
}
public short getLowBound() {
return lowBound;
}
/**
* converts a byte array into a log record instance
*/
public boolean read(byte[] bArr, int start) throws ChaiDBException {
/* construct a new LogRecord instance */
super.read(bArr, start);
/* get the values of BTreeMoveLogRecord Object */
int step = start + super.getRecordLength();
lowBound = ByteTool.bytesToShort(bArr, step, msbFirst);
step = step + LOWBOUND_SIZE;
upperBound = ByteTool.bytesToShort(bArr, step, msbFirst);
step = step + UPPERBOUND_SIZE;
headArr = ByteTool.copyByteArray(bArr, step, lowBound);
step = step + lowBound;
dataArr = ByteTool.copyByteArray(bArr, step, BTreeSpec.PAGE_SIZE - upperBound);
return true;
}
/**
* do redo function
*
* @param page
* @return boolean true|false
* update date:2001-10-12 by marriane,delete freelist recover
*/
protected boolean doRedo(byte[] page) throws ChaiDBException {
/* redo allocate a new page function */
/* free the allocated page function */
try {
/* add page to freelist of BufferedPage in memory*/
PageBufferManager bp = bpm;
bp.addToFreeList(treeId, super.getPageNum(), new Integer(super.getTxnId()));
return true;
} catch (Exception e) {
logger.debug(e);
throw new ChaiDBException(ErrorCode.LOG_REDO_FAILED, e.toString());
}
}
/**
* do undo function
*
* @param page
* @return boolean true|false
* update date:2001-10-12 by marriane,delete freelist recover
*/
protected boolean doUndo(byte[] page) throws ChaiDBException {
try {
/* copy old page content to page */
System.arraycopy(this.headArr, 0, page, 0, lowBound);
System.arraycopy(this.dataArr, 0, page, upperBound, BTreeSpec.PAGE_SIZE - upperBound);
return true;
} catch (Exception e) {
logger.debug(e);
throw new ChaiDBException(ErrorCode.LOG_UNDO_FAILED, e.toString());
}
}
/**
* print data and help in debugging log files
*/
public void print() throws ChaiDBException {
//logger.log(ServerLog.LOG_DEBUG,"begin: printing the information of BTreeFreeOverflowPageLogRecord object......");
super.print();
logger.debug("lowBound:" + lowBound + " upperBound:" + upperBound);
logger.debug("head array:" + ByteTool.toHexString(1, headArr, 0, headArr.length));
logger.debug("data array:" + ByteTool.toHexString(1, dataArr, 0, dataArr.length));
//logger.log(ServerLog.LOG_DEBUG,"end: printing the information of BTreeFreeOverflowPageLogRecord object.");
return;
}
/**
* converts a log record instance into a byte array.
* The byte array has the following format:
* --------------------------------------------------
* | lowBound | upperBound | headArr | dataArr
* --------------------------------------------------
* <p/>
* lowBound: 2 bytes.
* upperBound:2 bytes
* headArr: lowBound bytes
* dataArr: BTreeSpec.PAGE_SIZE-upperBound bytes
*/
public void toBytes(byte[] byteArray, int start) throws ChaiDBException {
super.toBytes(byteArray, start);
int step = start + super.getRecordLength();
ByteTool.shortToBytes(byteArray, step, lowBound);
step += LOWBOUND_SIZE;
ByteTool.shortToBytes(byteArray, step, upperBound);
step += UPPERBOUND_SIZE;
System.arraycopy(headArr, 0, byteArray, step, lowBound);
step += lowBound;
System.arraycopy(dataArr, 0, byteArray, step, BTreeSpec.PAGE_SIZE - upperBound);
}
/**
* get current log record type total length
*
* @return int total lenth
*/
public int getRecordLength() {
return super.getRecordLength() + LOWBOUND_SIZE + UPPERBOUND_SIZE + lowBound + (BTreeSpec.PAGE_SIZE - upperBound);
}
}