org.metafacture.statistics.AbstractCountProcessor Maven / Gradle / Ivy

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/*
 * Copyright 2013, 2014 Deutsche Nationalbibliothek
 *
 * Licensed 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.metafacture.statistics;

import java.util.Hashtable;
import java.util.Map;
import java.util.regex.Pattern;

import org.metafacture.framework.ObjectReceiver;
import org.metafacture.framework.helpers.DefaultObjectPipe;
import org.metafacture.framework.objects.Triple;

/**
 * Base class for operating on count data. The expected inputs are triples
 * containing as subject the variable name and as object the count. Marginal
 * counts must appear first, joint counts second. Marinal counts must be written
 * as 1:VARNAME, Joint counts as 2:FIRSTVARNAME&SECONDVARNAME.
 *
 * @author Markus Michael Geipel
 */
public abstract class AbstractCountProcessor extends DefaultObjectPipe> {


    private static final Pattern KEY_SPLIT_PATTERN = Pattern.compile("&", Pattern.LITERAL);

    private static final String MARGINAL_PREFIX = "1:";
    private static final String JOINT_PREFIX = "2:";

    private final Map marginals = new Hashtable();
    private boolean inHeader = true;
    private int minCount;

    protected final int getTotal() {
        return getMarginal("");
    }

    protected final void setMinCount(final int min) {
        minCount = min;
    }

    @Override
    public final void process(final Triple triple) {
        if (triple.getSubject().indexOf('&') == -1) {
            if (!inHeader) {
                throw new IllegalArgumentException(
                        "Marginal counts and joint count must not be mixed. Marginal counts must appear first, joint counts second");
            }
            if (!triple.getSubject().startsWith(MARGINAL_PREFIX)) {
                throw new IllegalArgumentException("Marginal counts must start with '1:'");
            }
            final int marginal = Integer.parseInt(triple.getObject());
            if (marginal >= minCount) {

                marginals.put(triple.getSubject().substring(2), Integer.valueOf(marginal));
            }

        } else {
            inHeader = false;
            if (!triple.getSubject().startsWith(JOINT_PREFIX)) {
                throw new IllegalArgumentException("Joint counts must start with '2:'");
            }

            final int nab = Integer.parseInt(triple.getObject());
            final String[] keyParts = KEY_SPLIT_PATTERN.split(triple.getSubject().substring(2));
            if (nab >= minCount) {

                final int na = getMarginal(keyParts[0]);
                final int nb = getMarginal(keyParts[1]);
                processCount(keyParts[0], keyParts[1], na, nb, nab);
            }
        }
    }

    protected abstract void processCount(final String varA, final String varB, final int countA, final int countB,
            final int countAandB);

    private int getMarginal(final String string) {
        final Integer value = marginals.get(string);
        if(null==value){
            return 0;
        }
        return value.intValue();
    }

    @Override
    protected final void onResetStream() {
        marginals.clear();
        inHeader = true;
        reset();
    }

    protected void reset() {
        // nothing to do

    }

    @Override
    protected final void onCloseStream() {
        onResetStream();
        close();
    }

    protected void close() {
        // nothing to do

    }

}