org.apache.lucene.queries.function.valuesource.DualFloatFunction.java Source code

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Here is the source code for org.apache.lucene.queries.function.valuesource.DualFloatFunction.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.queries.function.valuesource;

import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.queries.function.docvalues.FloatDocValues;
import org.apache.lucene.search.IndexSearcher;

import java.io.IOException;
import java.util.Map;

/**
 * Abstract {@link ValueSource} implementation which wraps two ValueSources
 * and applies an extendible float function to their values.
 **/
public abstract class DualFloatFunction extends ValueSource {
    protected final ValueSource a;
    protected final ValueSource b;

    /**
      * @param   a  the base.
      * @param   b  the exponent.
      */
    public DualFloatFunction(ValueSource a, ValueSource b) {
        this.a = a;
        this.b = b;
    }

    protected abstract String name();

    protected abstract float func(int doc, FunctionValues aVals, FunctionValues bVals) throws IOException;

    @Override
    public String description() {
        return name() + "(" + a.description() + "," + b.description() + ")";
    }

    @Override
    public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException {
        final FunctionValues aVals = a.getValues(context, readerContext);
        final FunctionValues bVals = b.getValues(context, readerContext);
        return new FloatDocValues(this) {
            @Override
            public float floatVal(int doc) throws IOException {
                return func(doc, aVals, bVals);
            }

            /** 
             * True if and only if <em>all</em> of the wrapped {@link FunctionValues} 
             * <code>exists</code> for the specified doc 
             */
            @Override
            public boolean exists(int doc) throws IOException {
                return MultiFunction.allExists(doc, aVals, bVals);
            }

            @Override
            public String toString(int doc) throws IOException {
                return name() + '(' + aVals.toString(doc) + ',' + bVals.toString(doc) + ')';
            }
        };
    }

    @Override
    public void createWeight(Map context, IndexSearcher searcher) throws IOException {
        a.createWeight(context, searcher);
        b.createWeight(context, searcher);
    }

    @Override
    public int hashCode() {
        int h = a.hashCode();
        h ^= (h << 13) | (h >>> 20);
        h += b.hashCode();
        h ^= (h << 23) | (h >>> 10);
        h += name().hashCode();
        return h;
    }

    @Override
    public boolean equals(Object o) {
        if (this.getClass() != o.getClass())
            return false;
        DualFloatFunction other = (DualFloatFunction) o;
        return this.a.equals(other.a) && this.b.equals(other.b);
    }
}