/*
* 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.lucene.spatial.util;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
/**
* Caches the doubleVal of another value source in a HashMap
* so that it is computed only once.
* @lucene.internal
*/
public class CachingDoubleValueSource extends ValueSource {
final ValueSource source;
final Map<Integer, Double> cache;
public CachingDoubleValueSource( ValueSource source )
{
this.source = source;
cache = new HashMap<Integer, Double>();
}
@Override
public String description() {
return "Cached["+source.description()+"]";
}
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
final int base = readerContext.docBase;
final FunctionValues vals = source.getValues(context,readerContext);
return new FunctionValues() {
@Override
public double doubleVal(int doc) {
Integer key = Integer.valueOf( base+doc );
Double v = cache.get( key );
if( v == null ) {
v = Double.valueOf( vals.doubleVal(doc) );
cache.put( key, v );
}
return v.doubleValue();
}
@Override
public float floatVal(int doc) {
return (float)doubleVal(doc);
}
@Override
public String toString(int doc) {
return doubleVal(doc)+"";
}
};
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
CachingDoubleValueSource that = (CachingDoubleValueSource) o;
if (source != null ? !source.equals(that.source) : that.source != null) return false;
return true;
}
@Override
public int hashCode() {
return source != null ? source.hashCode() : 0;
}
}