Jplag/core/src/main/java/de/jplag/JPlag.java

package de.jplag;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import de.jplag.clustering.ClusteringFactory;
import de.jplag.exceptions.ExitException;
import de.jplag.exceptions.SubmissionException;
import de.jplag.options.JPlagOptions;
import de.jplag.strategy.ComparisonMode;
import de.jplag.strategy.ComparisonStrategy;
import de.jplag.strategy.NormalComparisonStrategy;
import de.jplag.strategy.ParallelComparisonStrategy;

/**
 * This class coordinates the whole errorConsumer flow.
 */
public class JPlag {
    private static final Logger logger = LoggerFactory.getLogger(JPlag.class);

    private final JPlagOptions options;

    private final Language language;
    private final ComparisonStrategy comparisonStrategy;
    private final GreedyStringTiling coreAlgorithm; // Contains the comparison logic.

    /**
     * Creates and initializes a JPlag instance, parameterized by a set of options.
     * @param options determines the parameterization.
     */
    public JPlag(JPlagOptions options) {
        this.options = options;
        coreAlgorithm = new GreedyStringTiling(options);
        language = this.options.language();
        comparisonStrategy = initializeComparisonStrategy(options.comparisonMode());
    }

    /**
     * Main procedure, executes the comparison of source code submissions.
     * @return the results of the comparison, specifically the submissions whose similarity exceeds a set threshold.
     * @throws ExitException if the JPlag exits preemptively.
     */
    public JPlagResult run() throws ExitException {
        // Parse and validate submissions.
        SubmissionSetBuilder builder = new SubmissionSetBuilder(language, options);
        SubmissionSet submissionSet = builder.buildSubmissionSet();

        int submissionCount = submissionSet.numberOfSubmissions();
        if (submissionCount < 2) {
            throw new SubmissionException("Not enough valid submissions! (found " + submissionCount + " valid submissions)");
        }

        // Compare valid submissions.
        JPlagResult result = comparisonStrategy.compareSubmissions(submissionSet);
        if (logger.isInfoEnabled())
            logger.info("Total time for comparing submissions: {}", TimeUtil.formatDuration(result.getDuration()));

        result.setClusteringResult(ClusteringFactory.getClusterings(result.getAllComparisons(), options.clusteringOptions()));

        return result;
    }

    private ComparisonStrategy initializeComparisonStrategy(final ComparisonMode comparisonMode) {
        return switch (comparisonMode) {
            case NORMAL -> new NormalComparisonStrategy(options, coreAlgorithm);
            case PARALLEL -> new ParallelComparisonStrategy(options, coreAlgorithm);
        };
    }
}