org.apache.lucene.spatial.strategy.util.CachingDoubleValueSource.java Source code

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Here is the source code for org.apache.lucene.spatial.strategy.util.CachingDoubleValueSource.java

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/*
 * 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.strategy.util;

import org.apache.commons.lang.builder.HashCodeBuilder;
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;

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 obj) {
        if (obj == null) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        if (obj.getClass() != getClass()) {
            return false;
        }
        CachingDoubleValueSource rhs = (CachingDoubleValueSource) obj;
        return source.equals(rhs.source);
    }

    @Override
    public int hashCode() {
        return new HashCodeBuilder(61, 23).append(source).toHashCode();
    }
}