cc.kave.commons.pointsto.evaluation.ContextSampler.java Source code

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Here is the source code for cc.kave.commons.pointsto.evaluation.ContextSampler.java

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/**
 * Copyright 2016 Simon Reu
 *
 * 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 cc.kave.commons.pointsto.evaluation;

import java.io.IOException;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

import org.apache.commons.math3.random.RandomGenerator;

import com.google.inject.Inject;

import cc.kave.commons.model.events.completionevents.Context;
import cc.kave.commons.model.ssts.impl.SST;
import cc.kave.commons.pointsto.io.IOHelper;
import cc.kave.commons.pointsto.io.ZipArchive;
import cc.kave.commons.utils.json.JsonUtils;

public class ContextSampler {

    private final RandomGenerator rndGenerator;

    @Inject
    public ContextSampler(RandomGenerator rndGenerator) {
        this.rndGenerator = rndGenerator;
    }

    public List<Context> sample(Path contextsDirectory, int number) throws IOException {
        Map<ZipArchive, Integer> registry = buildRegistry(contextsDirectory);

        try {
            int totalNumContexts = registry.values().stream().mapToInt(Integer::intValue).sum();
            LinkedHashSet<Integer> contextIndices = new LinkedHashSet<>();
            if (totalNumContexts < number) {
                for (int i = 0; i < totalNumContexts; ++i) {
                    contextIndices.add(i);
                }
            } else {
                for (int i = 0; i < number; ++i) {
                    int index;
                    do {
                        index = rndGenerator.nextInt(totalNumContexts);
                    } while (contextIndices.contains(index));
                    contextIndices.add(index);
                }
            }

            List<Context> contexts = new ArrayList<>(number);
            for (Integer index : contextIndices) {
                Context ctxt = getContext(registry, index);
                if (ctxt == null) {
                    ctxt = new Context();
                }
                contexts.add(ctxt);
            }

            return contexts;
        } finally {
            closeRegistry(registry);
        }
    }

    private Map<ZipArchive, Integer> buildRegistry(Path contextsDirectory) throws IOException {
        Map<ZipArchive, Integer> registry = new LinkedHashMap<>();
        for (Path zipFile : IOHelper.getZipFiles(contextsDirectory)) {
            ZipArchive archive = new ZipArchive(zipFile);
            registry.put(archive, archive.getFiles().size());
        }
        return registry;
    }

    private Context getContext(Map<ZipArchive, Integer> registry, int index) throws IOException {
        int startIndex = 0;
        for (Map.Entry<ZipArchive, Integer> entry : registry.entrySet()) {
            int nextStartIndex = startIndex + entry.getValue();
            if (index < nextStartIndex) {
                ZipArchive archive = entry.getKey();
                Path contextFile = archive.getFiles().get(index - startIndex);
                return archive.load(contextFile, Context.class, JsonUtils::fromJson);
            }
            startIndex = nextStartIndex;
        }

        throw new IllegalArgumentException();
    }

    private void closeRegistry(Map<ZipArchive, Integer> registry) throws IOException {
        for (ZipArchive archive : registry.keySet()) {
            archive.close();
        }
    }

}