/*
* Copyright 2010 JBoss Inc
*
* Licensed 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.drools.core.util;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import org.drools.core.util.RightTupleIndexHashTable.FullFastIterator;
import org.drools.reteoo.LeftTuple;
import org.drools.reteoo.LeftTuple;
import org.drools.reteoo.LeftTupleMemory;
import org.drools.reteoo.RightTuple;
public class LeftTupleIndexHashTable extends AbstractHashTable
implements
LeftTupleMemory {
private static final long serialVersionUID = 510l;
public static final int PRIME = 31;
private int startResult;
private transient FieldIndexHashTableFullIterator tupleValueFullIterator;
private int factSize;
private Index index;
public LeftTupleIndexHashTable() {
// constructor for serialisation
}
public LeftTupleIndexHashTable(final FieldIndex[] index) {
this( 128,
0.75f,
index );
}
public LeftTupleIndexHashTable(final int capacity,
final float loadFactor,
final FieldIndex[] index) {
super( capacity,
loadFactor );
this.startResult = LeftTupleIndexHashTable.PRIME;
for ( int i = 0, length = index.length; i < length; i++ ) {
this.startResult += LeftTupleIndexHashTable.PRIME * this.startResult + index[i].getExtractor().getIndex();
}
switch ( index.length ) {
case 0 :
throw new IllegalArgumentException( "FieldIndexHashTable cannot use an index[] of length 0" );
case 1 :
this.index = new SingleIndex( index,
this.startResult );
break;
case 2 :
this.index = new DoubleCompositeIndex( index,
this.startResult );
break;
case 3 :
this.index = new TripleCompositeIndex( index,
this.startResult );
break;
default :
throw new IllegalArgumentException( "FieldIndexHashTable cannot use an index[] of length great than 3" );
}
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
super.readExternal( in );
startResult = in.readInt();
factSize = in.readInt();
index = (Index) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
super.writeExternal( out );
out.writeInt( startResult );
out.writeInt( factSize );
out.writeObject( index );
}
public Iterator iterator() {
if ( this.tupleValueFullIterator == null ) {
this.tupleValueFullIterator = new FieldIndexHashTableFullIterator( this );
} else {
this.tupleValueFullIterator.reset();
}
return this.tupleValueFullIterator;
}
public FastIterator fastIterator() {
return LinkedList.fastIterator;
}
public FastIterator fullFastIterator() {
return new FullFastIterator( this.table );
}
public FastIterator fullFastIterator(LeftTuple leftTuple) {
final int hashCode = this.index.hashCodeOf( leftTuple );
final int row = indexOf( hashCode,
this.table.length );
return new FullFastIterator( this.table, row );
}
public static class FullFastIterator implements FastIterator {
private Entry[] table;
private int row;
public FullFastIterator(Entry[] table, int row) {
this.table = table;
this.row = row + 1;
}
public FullFastIterator(Entry[] table) {
this.table = table;
this.row = 0;
}
public Entry next(Entry object) {
LeftTuple leftTuple = ( LeftTuple ) object;
LeftTupleList list = null;
if ( leftTuple != null ) {
list = leftTuple.getMemory(); // assumes you do not pass in a null RightTuple
}
int length = table.length;
while ( this.row < length ) {
// check if there is a current bucket
while ( list == null ) {
// iterate while there is no current bucket, trying each array position
list = (LeftTupleList) this.table[this.row];
this.row++;
if ( list != null ) {
// we have a bucket so assign the frist LeftTuple and return
leftTuple = (LeftTuple) list.getFirst( );
return leftTuple;
} else if ( this.row >= length ) {
// we've scanned the whole table and nothing is left, so return null
return null;
}
}
leftTuple = (LeftTuple) leftTuple.getNext();
if ( leftTuple != null ) {
// we have a next tuple so return
return leftTuple;
} else {
list = (LeftTupleList) list.getNext();
// try the next bucket if we have a shared array position
if ( list != null ) {
// if we have another bucket, assign the first LeftTuple and return
leftTuple = (LeftTuple) list.getFirst( );
return leftTuple;
}
}
}
return null;
}
public boolean isFullIterator() {
return true;
}
}
public LeftTuple getFirst(final RightTuple rightTuple) {
LeftTupleList bucket = get( rightTuple );
if ( bucket != null ) {
return bucket.getFirst( );
} else {
return null;
}
}
public LeftTuple getFirst(final LeftTuple leftTuple) {
final LeftTupleList bucket = get( leftTuple );
if ( bucket != null ) {
return bucket.getFirst( );
} else {
return null;
}
}
public boolean isIndexed() {
return true;
}
public Index getIndex() {
return this.index;
}
public Entry getBucket(final Object object) {
final int hashCode = this.index.hashCodeOf( object );
final int index = indexOf( hashCode,
this.table.length );
return this.table[index];
}
@Override
public int getResizeHashcode(Entry entry) {
// Entry is always LeftTupleList which caches the hashcode, so just return it
return entry.hashCode();
}
public static class FieldIndexHashTableFullIterator
implements
Iterator {
private AbstractHashTable hashTable;
private Entry[] table;
private int row;
private int length;
private LeftTupleList list;
private LeftTuple leftTuple;
public FieldIndexHashTableFullIterator(final AbstractHashTable hashTable) {
this.hashTable = hashTable;
reset();
}
/* (non-Javadoc)
* @see org.drools.util.Iterator#next()
*/
public Object next() {
while ( this.row < this.length ) {
// check if there is a current bucket
while ( this.list == null ) {
// iterate while there is no current bucket, trying each array position
this.list = (LeftTupleList) this.table[this.row];
this.row++;
if ( this.list != null ) {
// we have a bucket so assign the first LeftTuple and return
this.leftTuple = (LeftTuple) this.list.getFirst( );
return this.leftTuple;
} else if ( this.row >= this.length ) {
// we've scanned the whole table and nothing is left, so return null
return null;
}
}
this.leftTuple = (LeftTuple) this.leftTuple.getNext();
if ( this.leftTuple != null ) {
// we have a next tuple so return
return this.leftTuple;
} else {
this.list = (LeftTupleList) this.list.getNext();
// try the next bucket if we have a shared array position
if ( this.list != null ) {
// if we have another bucket, assign the first LeftTuple and return
this.leftTuple = (LeftTuple) this.list.getFirst( );
return this.leftTuple;
}
}
}
return null;
}
public void remove() {
throw new UnsupportedOperationException( "FieldIndexHashTableFullIterator does not support remove()." );
}
/* (non-Javadoc)
* @see org.drools.util.Iterator#reset()
*/
public void reset() {
this.table = this.hashTable.getTable();
this.length = this.table.length;
this.row = 0;
this.list = null;
this.leftTuple = null;
}
}
public LeftTuple[] toArray() {
LeftTuple[] result = new LeftTuple[this.factSize];
int index = 0;
for ( int i = 0; i < this.table.length; i++ ) {
LeftTupleList bucket = (LeftTupleList) this.table[i];
while ( bucket != null ) {
LeftTuple entry = (LeftTuple) bucket.getFirst( );
while ( entry != null ) {
result[index++] = entry;
entry = (LeftTuple) entry.getNext();
}
bucket = (LeftTupleList) bucket.getNext();
}
}
return result;
}
public void removeAdd(LeftTuple leftTuple) {
LeftTupleList memory = leftTuple.getMemory();
memory.remove( leftTuple );
final int newHashCode = this.index.hashCodeOf( leftTuple );
if ( newHashCode == memory.hashCode() ) {
// it's the same bucket, so re-use and return
memory.add( leftTuple );
return;
}
// bucket is empty so remove.
this.factSize--;
if ( memory.first == null ) {
final int index = indexOf( memory.hashCode(),
this.table.length );
LeftTupleList previous = null;
LeftTupleList current = (LeftTupleList) this.table[index];
while ( current != memory ) {
previous = current;
current = (LeftTupleList) current.getNext();
}
if ( previous != null ) {
previous.next = current.next;
} else {
this.table[index] = current.next;
}
this.size--;
}
add( leftTuple );
}
public void add(final LeftTuple tuple) {
final LeftTupleList entry = getOrCreate( tuple );
entry.add( tuple );
this.factSize++;
}
public void remove(final LeftTuple leftTuple) {
LeftTupleList memory = leftTuple.getMemory();
memory.remove( leftTuple );
this.factSize--;
if ( memory.first == null ) {
final int index = indexOf( memory.hashCode(),
this.table.length );
LeftTupleList previous = null;
LeftTupleList current = (LeftTupleList) this.table[index];
while ( current != memory ) {
previous = current;
current = (LeftTupleList) current.getNext();
}
if ( previous != null ) {
previous.next = current.next;
} else {
this.table[index] = current.next;
}
this.size--;
}
leftTuple.setNext( null );
leftTuple.setPrevious( null );
}
public boolean contains(final LeftTuple tuple) {
final int hashCode = this.index.hashCodeOf( tuple );
final int index = indexOf( hashCode,
this.table.length );
LeftTupleList current = (LeftTupleList) this.table[index];
while ( current != null ) {
if ( current.matches( tuple,
hashCode ) ) {
return true;
}
current = (LeftTupleList) current.next;
}
return false;
}
public LeftTupleList get(final RightTuple rightTuple) {
final Object object = rightTuple.getFactHandle().getObject();
final int hashCode = this.index.hashCodeOf( object );
final int index = indexOf( hashCode,
this.table.length );
LeftTupleList entry = (LeftTupleList) this.table[index];
while ( entry != null ) {
if ( entry.matches( object,
hashCode ) ) {
return entry;
}
entry = (LeftTupleList) entry.getNext();
}
return entry;
}
/**
* We use this method to aviod to table lookups for the same hashcode; which is what we would have to do if we did
* a get and then a create if the value is null.
*
* @param value
* @return
*/
private LeftTupleList getOrCreate(final LeftTuple tuple) {
final int hashCode = this.index.hashCodeOf( tuple );
final int index = indexOf( hashCode,
this.table.length );
LeftTupleList entry = (LeftTupleList) this.table[index];
// search to find an existing entry
while ( entry != null ) {
if ( entry.matches( tuple,
hashCode ) ) {
return entry;
}
entry = (LeftTupleList) entry.next;
}
// entry does not exist, so create
if ( entry == null ) {
entry = new LeftTupleList( this.index,
hashCode );
entry.next = this.table[index];
this.table[index] = entry;
if ( this.size++ >= this.threshold ) {
resize( 2 * this.table.length );
}
}
return entry;
}
private LeftTupleList get(final LeftTuple tuple) {
final int hashCode = this.index.hashCodeOf( tuple );
final int index = indexOf( hashCode,
this.table.length );
LeftTupleList entry = (LeftTupleList) this.table[index];
// search to find an existing entry
while ( entry != null ) {
if ( entry.matches( tuple,
hashCode ) ) {
return entry;
}
entry = (LeftTupleList) entry.next;
}
return entry;
}
public int size() {
return this.factSize;
}
public String toString() {
StringBuilder builder = new StringBuilder();
Iterator it = iterator();
for ( LeftTuple leftTuple = (LeftTuple) it.next(); leftTuple != null; leftTuple = (LeftTuple) it.next() ) {
builder.append( leftTuple + "\n" );
}
return builder.toString();
}
}