EventsFileFingerprintComparator.java

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package org.matsim.utils.eventsfilecomparison;

import it.unimi.dsi.fastutil.objects.Object2IntMap;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.matsim.core.api.experimental.events.EventsManager;
import org.matsim.core.events.EventsUtils;

import javax.annotation.Nullable;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.Arrays;

public final class EventsFileFingerprintComparator {

    private static final Logger log = LogManager.getLogger(EventsFileComparator.class);

    private EventsFileFingerprintComparator() {
    }


    public static FingerprintEventHandler createFingerprintHandler(final String eventsfile, @Nullable String compareFingerprint) {

        EventFingerprint fp = null;
        Exception err = null;
        if (compareFingerprint != null) {
            try {
                fp = EventFingerprint.read(compareFingerprint);
            } catch (Exception e) {
                log.warn("Could not read compare fingerprint from file: {}", compareFingerprint, e);
                fp = new EventFingerprint();
                err = e;
            }
        }

        FingerprintEventHandler handler = new FingerprintEventHandler(fp);

        EventsManager manager = EventsUtils.createEventsManager();

        manager.addHandler(handler);

        EventsUtils.readEvents(manager, eventsfile);

        manager.finishProcessing();
        handler.finishProcessing();

        // File error overwrite any other error
        if (err != null) {
            handler.setComparisonResult(ComparisonResult.FILE_ERROR);
            handler.setComparisonMessage(err.getMessage());
        }

        return handler;
    }

    public static ComparisonResult compareFingerprints(final String fp1, final String fp2) {

        EventFingerprint fingerprint1;
        EventFingerprint fingerprint2;
        try {
            fingerprint1 = EventFingerprint.read(fp1);
            fingerprint2 = EventFingerprint.read(fp2);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }

        String logMessage = "";
        //Check if time array size is the same
        if (fingerprint1.timeArray.size() != fingerprint2.timeArray.size()) {
            logMessage = "Different number of timesteps";
            log.warn(logMessage);
            return ComparisonResult.DIFFERENT_NUMBER_OF_TIMESTEPS;
        }

        //Check if both time arrays have the same timesteps
        if (!Arrays.equals(fingerprint1.timeArray.toFloatArray(), fingerprint2.timeArray.toFloatArray())) {
            logMessage = "Different timesteps";
            log.warn(logMessage);
            return ComparisonResult.DIFFERENT_TIMESTEPS;
        }


        //Check which event type counts are different among 2 fingerprints
        boolean countDiffers = false;
        for (Object2IntMap.Entry<String> entry1 : fingerprint1.eventTypeCounter.object2IntEntrySet()) {
            String key = entry1.getKey();
            int count1 = entry1.getIntValue();
            int count2 = fingerprint2.eventTypeCounter.getInt(key);
            if (count1 != count2) {
                countDiffers = true;

                if (!logMessage.isEmpty())
                    logMessage += "\n";

                logMessage += "Count for event type '%s' differs: %d != %d".formatted(key, count1, count2);
            }
        }
        if (countDiffers) {
            log.warn(logMessage);
            return ComparisonResult.WRONG_EVENT_COUNT;
        }


        //Check if total hash is the same
        byte[] hash1 = fingerprint1.hash;
        byte[] hash2 = fingerprint2.hash;
        if (!Arrays.equals(hash1, hash2)) {

            logMessage = String.format("Difference occurred hash codes hash of first file is %s, hash of second is %s", Arrays.toString(hash1), Arrays.toString(hash2));

            log.warn(logMessage);
            return ComparisonResult.DIFFERENT_EVENT_ATTRIBUTES;
        }

        return ComparisonResult.FILES_ARE_EQUAL;

    }
}