/**
* 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 org.apache.jena.sparql.engine.join;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.jena.atlas.iterator.Iter;
import org.apache.jena.ext.com.google.common.collect.ArrayListMultimap;
import org.apache.jena.ext.com.google.common.collect.Multimap;
import org.apache.jena.sparql.engine.binding.Binding;
import org.apache.jena.sparql.engine.join.JoinKey ;
/** The probe table for a hash join */
class HashProbeTable {
/*package*/ long s_count = 0;
/*package*/ long s_bucketCount = 0;
/*package*/ long s_maxBucketSize = 0;
/*package*/ long s_noKeyBucketSize = 0;
/*package*/ long s_maxMatchGroup = 0;
/*package*/ long s_countScanMiss = 0;
private final List<Binding> noKeyBucket = new ArrayList<>();
private final Multimap<Object, Binding> buckets;
private final JoinKey joinKey;
HashProbeTable(JoinKey joinKey) {
this.joinKey = joinKey;
buckets = ArrayListMultimap.create();
}
public void put(Binding row) {
s_count++;
Object longHash = JoinLib.hash(joinKey, row);
if ( longHash == JoinLib.noKeyHash ) {
noKeyBucket.add(row);
return;
}
buckets.put(longHash, row);
}
public Iterator<Binding> getCandidates(Binding row) {
Iterator<Binding> iter = null;
Object longHash = JoinLib.hash(joinKey, row);
if ( longHash == JoinLib.noKeyHash )
iter = buckets.values().iterator();
else {
Collection<Binding> x = buckets.get(longHash);
if ( x != null ) {
s_maxMatchGroup = Math.max(s_maxMatchGroup, x.size());
iter = x.iterator();
} else {
s_countScanMiss ++ ;
}
}
// And the rows with no common hash key
if ( noKeyBucket != null )
iter = Iter.concat(iter, noKeyBucket.iterator());
return iter;
}
public void stats() {
long max = 0;
for ( Object key : buckets.keys() ) {
long s = buckets.get(key).size();
max = Math.max(max, s);
}
s_maxBucketSize = max;
s_bucketCount = buckets.keys().size();
s_noKeyBucketSize = (noKeyBucket == null) ? 0 : noKeyBucket.size();
// s_count
// s_maxMatchGroup
// What to do with them?
}
// Should not need these operations.
public Collection<Binding> getNoKey$() {
if ( noKeyBucket == null )
return null;
return noKeyBucket;
}
public Collection<Binding> getHashMatch$(Binding row) {
Object longHash = JoinLib.hash(joinKey, row);
if ( longHash == JoinLib.noKeyHash )
return noKeyBucket;
Collection<Binding> list = buckets.get(longHash);
return list;
}
public Iterator<Binding> values() {
return Iter.concat(buckets.values().iterator(),
noKeyBucket.iterator()) ;
}
public void clear() {
buckets.clear();
}
}