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/*
 * Copyright (c) 2000, 2020, Oracle and/or its affiliates.
 *
 * Licensed under the Universal Permissive License v 1.0 as shown at
 * http://oss.oracle.com/licenses/upl.
 */

package com.tangosol.util.filter;


import com.tangosol.util.Filter;
import com.tangosol.util.MapIndex;
import com.tangosol.util.ValueExtractor;

import java.util.Map;
import java.util.Set;


/**
* Filter which compares the result of a method invocation with a value for
* equality.
*
* @param  the type of the input argument to the filter
* @param  the type of the value to use for comparison
*
* @author cp/gg 2002.10.27
*/
public class EqualsFilter
        extends    ComparisonFilter
        implements IndexAwareFilter
    {
    // ----- constructors ---------------------------------------------------

    /**
    * Default constructor (necessary for the ExternalizableLite interface).
    */
    public EqualsFilter()
        {
        }

    /**
    * Construct an EqualsFilter for testing equality.
    *
    * @param extractor the ValueExtractor to use by this filter
    * @param value     the object to compare the result with
    */
    public EqualsFilter(ValueExtractor extractor, E value)
        {
        super(extractor, value);
        }

    /**
    * Construct an EqualsFilter for testing equality.
    *
    * @param sMethod  the name of the method to invoke via reflection
    * @param value    the object to compare the result with
    */
    public EqualsFilter(String sMethod, E value)
        {
        super(sMethod, value);
        }


    // ----- ExtractorFilter methods ----------------------------------------

    /**
    * {@inheritDoc}
    */
    protected boolean evaluateExtracted(E extracted)
        {
        return equals(extracted, getValue());
        }


    // ----- IndexAwareFilter interface -------------------------------------

    /**
    * {@inheritDoc}
    */
    public int calculateEffectiveness(Map mapIndexes, Set setKeys)
        {
        return calculateMatchEffectiveness(mapIndexes, setKeys);
        }

    /**
    * {@inheritDoc}
    */
    public Filter applyIndex(Map mapIndexes, Set setKeys)
        {
        MapIndex index = (MapIndex) mapIndexes.get(getValueExtractor());
        if (index == null)
            {
            // there is no relevant index
            return this;
            }
        else
            {
            Set setEquals = (Set) index.getIndexContents().get(getValue());
            if (setEquals == null || setEquals.isEmpty())
                {
                setKeys.clear();
                }
            else
                {
                setKeys.retainAll(setEquals);
                }
            return null;
            }
        }
    }