cc.recommenders.io.ReadingArchive.java Source code

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Here is the source code for cc.recommenders.io.ReadingArchive.java

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/*******************************************************************************
 * Copyright (c) 2011 Darmstadt University of Technology.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Sebastian Proksch - initial API and implementation
 ******************************************************************************/
package cc.recommenders.io;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.lang.reflect.Type;
import java.nio.charset.Charset;
import java.util.Enumeration;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.apache.commons.io.IOUtils;

import com.google.common.collect.Lists;

import cc.kave.commons.utils.json.JsonUtils;
import cc.recommenders.assertions.Asserts;

public class ReadingArchive implements IReadingArchive {

    private ZipFile zipFile;
    private Enumeration<? extends ZipEntry> entries;

    public ReadingArchive(File file) {
        Asserts.assertTrue(file.exists());
        Asserts.assertTrue(file.isFile());
        try {
            zipFile = new ZipFile(file);
            entries = zipFile.entries();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public boolean hasNext() {
        return entries.hasMoreElements();
    }

    @Override
    public <T> T getNext(Type classOfT) {
        try {
            ZipEntry next = entries.nextElement();
            InputStream in = zipFile.getInputStream(next);
            T obj = JsonUtils.fromJson(in, classOfT);
            in.close();

            return obj;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public String getNextPlain() {
        try {
            ZipEntry next = entries.nextElement();
            InputStream in = zipFile.getInputStream(next);
            StringWriter writer = new StringWriter();
            IOUtils.copy(in, writer, Charset.defaultCharset().toString());
            String str = writer.toString();
            in.close();

            return str;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public <T> List<T> getAll(Class<T> c) {
        List<T> out = Lists.newLinkedList();
        while (hasNext()) {
            out.add(getNext(c));
        }
        return out;
    }

    @Override
    public int getNumberOfEntries() {
        return zipFile.size();
    }

    @Override
    public void close() {
        try {
            zipFile.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}