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Skeleton for a Recommendation Engine
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/*
 * Copyright (c) 2013-2016 GraphAware
 *
 * This file is part of the GraphAware Framework.
 *
 * GraphAware Framework is free software: you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of
 * the GNU General Public License along with this program.  If not, see
 * .
 */

package com.graphaware.reco.generic.post;

import com.graphaware.reco.generic.context.Context;
import com.graphaware.reco.generic.result.Recommendations;

/**
 * Base class for {@link PostProcessor} implementation that collects timing statistics about the process.
 *
 * @param  type of the post-processed recommendations.
 * @param   type of the item recommendations are for / based on.
 */
public abstract class BasePostProcessor implements PostProcessor {

    /**
     * Get the name of this post processor. This name should be unique within the overall recommendation engine structure and
     * will be used for naming scores produced by the post processor, as well as for collecting {@link com.graphaware.reco.generic.stats.Statistics}.
     *
     * @return name.
     */
    protected abstract String name();

    /**
     * {@inheritDoc}
     */
    @Override
    public final void postProcess(Recommendations recommendations, IN input, Context context) {
        context.statistics().startTiming(name());

        doPostProcess(recommendations, input, context);

        context.statistics().stopTiming(name());
    }

    /**
     * Post-process results.
     *
     * @param recommendations scored recommendations.
     * @param input           for whom the recommendation have been produced, must not be null.
     * @param context         for the recommendation computing process.
     */
    protected abstract void doPostProcess(Recommendations recommendations, IN input, Context context);

    /**
     * {@inheritDoc}
     */
    @Override
    public float maxPositiveScore(IN input, Context context) {
        return Float.POSITIVE_INFINITY;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public float maxNegativeScore(IN input, Context context) {
        return Float.NEGATIVE_INFINITY;
    }
}