/*
* 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.index.ext;
import static org.apache.jena.atlas.lib.Alg.decodeIndex ;
import java.nio.ByteBuffer ;
import org.apache.jena.atlas.lib.NotImplemented ;
import com.hp.hpl.jena.tdb.base.StorageException ;
import com.hp.hpl.jena.tdb.base.block.Block ;
import com.hp.hpl.jena.tdb.base.record.Record ;
import com.hp.hpl.jena.tdb.base.record.RecordFactory ;
import com.hp.hpl.jena.tdb.base.recordbuffer.RecordBufferPageBase ;
/** A HashBucket is a record buffer, with space store it's hash value and the bit length */
public final class HashBucket extends RecordBufferPageBase
{
// Offsets in the block.
// Count is 0.
final public static int TRIE = COUNT+4 ;
final public static int BITLEN = TRIE+4 ;
final public static int FIELD_LENGTH = BITLEN ; // Length of the space needed here (not count)
// Trie/Hash of this bucket.
private int trie ;
// How many bits are used for storing in this bucket.
private int bucketBitLen ;
public static HashBucket format(Block block, RecordFactory factory)
{
ByteBuffer byteBuffer = block.getByteBuffer() ;
int count = byteBuffer.getInt(COUNT) ;
int hash = byteBuffer.getInt(TRIE) ;
int hashLen = byteBuffer.getInt(BITLEN) ;
HashBucket bucket = new HashBucket(NO_ID, hash, hashLen, block, factory, count) ;
return bucket ;
}
public static HashBucket createBlank(Block block, RecordFactory factory)
{
ByteBuffer byteBuffer = block.getByteBuffer() ;
int count = 0 ;
int hash = -1 ;
int hashLen = -1 ;
HashBucket bucket = new HashBucket(NO_ID, hash, hashLen, block, factory, count) ;
return bucket ;
}
/** Create a bucket */
public HashBucket(int id, int hashValue, int bucketBitLen,
Block block,
RecordFactory factory,
int count)
{
super(block, FIELD_LENGTH, factory, count) ;
this.bucketBitLen = bucketBitLen ;
this.trie = hashValue ;
}
// Find the index of the key, return insertion a point if not found as -(i+1)
public final int findIndex(Record key)
{
int i = getRecordBuffer().find(key) ;
return i ;
}
public final Record find(Record key)
{
int i = getRecordBuffer().find(key) ;
if ( i < 0 )
return null ;
return getRecordBuffer().get(i) ;
}
// Return true is added a new value
public final boolean put(Record record)
{
int i = findIndex(record) ;
if ( i < 0 )
i = decodeIndex(i) ;
else
{
Record recordOrig = getRecordBuffer().get(i) ;
if ( record.equals(recordOrig) )
return false ;
// Same key, different values. Replace.
getRecordBuffer().set(i, record) ;
return true ;
}
if ( getRecordBuffer().isFull() )
throw new StorageException("Bucket overflow") ;
getRecordBuffer().add(i, record) ;
return true ;
}
public void set(int x, Record record)
{
getRecordBuffer().set(x, record) ;
}
public final boolean removeByKey(Record key)
{
int i = findIndex(key) ;
if ( i < 0 )
return false ;
getRecordBuffer().remove(i) ;
return true ;
}
@Override
public void _reset(Block block)
{ throw new NotImplemented("reset") ; }
public final boolean isFull()
{
return getRecordBuffer().isFull() ;
}
public final boolean isEmpty()
{
return getRecordBuffer().isEmpty() ;
}
// Return the item in slot idx
public final Record get(int idx)
{
if ( idx >= getRecordBuffer().size() )
return null ;
return getRecordBuffer().get(idx) ;
}
public final int getTrieValue() { return trie ; }
final void setTrieValue(int newHash) { trie = newHash; }
public final int getTrieBitLen() { return bucketBitLen ; }
public void setTrieLength(int trieBitLen) { bucketBitLen = trieBitLen ; }
//
// public void setPageMgr(HashBucketMgr pageMgr)
// {
// this.pageMgr = pageMgr;
// }
//
// public HashBucketMgr getPageMgr()
// {
// return pageMgr;
// }
final void incTrieBitLen() { bucketBitLen++ ; }
@Override
public String toString()
{
return String.format("HashBucket [id=%d, trie=0x%04X, bitlen=%d]: %s",getId(), getTrieValue(), getTrieBitLen(), getRecordBuffer().toString());
}
}