com.bigdata.btree.proc.AbstractKeyRangeIndexProcedure Maven / Gradle / Ivy
/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
[email protected]
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; version 2 of the License.
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Jan 28, 2008
*/
package com.bigdata.btree.proc;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import com.bigdata.mdi.ISeparatorKeys;
import com.bigdata.util.BytesUtil;
/**
* @author Bryan Thompson
*/
abstract public class AbstractKeyRangeIndexProcedure extends
AbstractIndexProcedure implements IKeyRangeIndexProcedure,
Externalizable {
protected byte[] fromKey;
protected byte[] toKey;
@Override
public byte[] getFromKey() {
return fromKey;
}
@Override
public byte[] getToKey() {
return toKey;
}
/**
* De-serialization ctor.
*/
public AbstractKeyRangeIndexProcedure() {
}
public AbstractKeyRangeIndexProcedure(final byte[] fromKey,
final byte[] toKey) {
this.fromKey = fromKey;
this.toKey = toKey;
}
@Override
public void readExternal(final ObjectInput in) throws IOException, ClassNotFoundException {
readKeys(in);
}
@Override
public void writeExternal(final ObjectOutput out) throws IOException {
writeKeys(out);
}
private static final short VERSION0 = 0x0;
protected void readKeys(final ObjectInput in) throws IOException, ClassNotFoundException {
final short version = in.readShort();
if (version != VERSION0) {
throw new IOException("Unknown version: " + version);
}
// fromKey
{
final int len = in.readInt();
if(len > 0) {
fromKey = new byte[len - 1];
in.readFully(fromKey);
}
}
// toKey
{
final int len = in.readInt();
if(len > 0) {
toKey = new byte[len - 1];
in.readFully(toKey);
}
}
}
protected void writeKeys(final ObjectOutput out) throws IOException {
out.writeShort(VERSION0);
/*
* Note: 0 indicates a null reference. Otherwise the length of the
* byte[] is written as (len + 1).
*/
out.writeInt(fromKey == null ? 0 : fromKey.length + 1);
if (fromKey != null) {
out.write(fromKey);
}
out.writeInt(toKey == null ? 0 : toKey.length + 1);
if (toKey != null) {
out.write(toKey);
}
}
/**
* Constrain the fromKey to lie within the index partition.
*
* @param fromKey
* The fromKey.
* @param pmd
* The index partition metadata (MAY be null).
*
* @return The fromKey -or- the leftSeparator key of the index
* partition IFF pmd is non-null AND the
* fromKey is LT the leftSeparator key.
*/
public static byte[] constrainFromKey(byte[] fromKey, final ISeparatorKeys pmd) {
if (pmd == null)
return fromKey;
if (fromKey != null) {
/*
* Choose the left separator key if the fromKey is strictly less
* than the left separator. This has the effect of constraining the
* fromKey to be within the index partition key range.
*/
final int ret = BytesUtil.compareBytes(fromKey, pmd
.getLeftSeparatorKey());
if (ret < 0) {
fromKey = pmd.getLeftSeparatorKey();
}
} else {
/*
* There is no lower bound, so accept the lower bound of the index
* partition.
*/
fromKey = pmd.getLeftSeparatorKey();
}
return fromKey;
}
/**
* Constrain the toKey to lie within the index partition.
*
* @param toKey
* The toKey.
* @param pmd
* The index partition metadata (MAY be null).
*
* @return The toKey -or- the rightSeparator key of the index
* partition IFF pmd is non-null AND the
* toKey is GT the rightSeparator key.
*/
public static byte[] constrainToKey(byte[] toKey, final ISeparatorKeys pmd) {
if (pmd == null)
return toKey;
if (toKey != null) {
if (pmd.getRightSeparatorKey() != null) {
/*
* Choose the right separator key if the toKey is strictly
* greater than the right separator key. This has the effect of
* constraining the toKey to be within the index partition key
* range.
*/
final int ret = BytesUtil.compareBytes(toKey, pmd
.getRightSeparatorKey());
if (ret > 0) {
toKey = pmd.getRightSeparatorKey();
}
}
} else {
/*
* If the toKey was unconstrained, then use the upper bound of the
* index partition. If this is the last index partition for an
* index, then the index partition will also have an unconstrained
* upper bound.
*/
toKey = pmd.getRightSeparatorKey();
}
return toKey;
}
}
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