edu.jhu.hlt.acute.iterators.tar.TarArchiveEntryByteIterator.java Source code

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Here is the source code for edu.jhu.hlt.acute.iterators.tar.TarArchiveEntryByteIterator.java

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/*
 * Copyright 2012-2015 Johns Hopkins University HLTCOE. All rights reserved.
 * See LICENSE in the project root directory.
 */
package edu.jhu.hlt.acute.iterators.tar;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;

import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.compress.utils.IOUtils;

import edu.jhu.hlt.utilt.AutoCloseableIterator;

/**
 * A class that provides the ability to iterate over all files in a
 * <code>.tar</code> archive. It skips folders, but will iterate
 * over files inside of them.
 */
public class TarArchiveEntryByteIterator implements AutoCloseableIterator<byte[]> {

    private final TarArchiveInputStream tis;

    /**
     * Wrap an {@link InputStream}.
     *
     * @throws IOException if there are issues with the underlying archive (it has no
     * files, for example)
     */
    public TarArchiveEntryByteIterator(InputStream is) throws IOException {
        this.tis = new TarArchiveInputStream(is);

        // Prepare next entry.
        this.tis.getNextTarEntry();
    }

    /**
     * Create this object based on a {@link Path}.
     *
     * @throws IOException
     */
    public TarArchiveEntryByteIterator(Path path) throws IOException {
        this(new BufferedInputStream(Files.newInputStream(path)));
    }

    @Override
    public boolean hasNext() {
        // possible states:
        // processed 1 file, and are now on a dir.
        // processed 1 file, and are now on another file.
        // done iterating (nothing left).

        // if any entry is null, done; return false.
        while (this.tis.getCurrentEntry() != null) {
            TarArchiveEntry entry = this.tis.getCurrentEntry();
            if (!entry.isDirectory())
                return true;
            else
                try {
                    this.tis.getNextEntry();
                } catch (IOException ioe) {
                    throw new RuntimeException(ioe);
                }
        }

        return this.tis.getCurrentEntry() != null;
    }

    @Override
    public byte[] next() {
        try {
            TarArchiveEntry entry = this.tis.getCurrentEntry();
            if (entry.isDirectory()) {
                // Recurse.
                this.tis.getNextTarEntry();
                this.next();
            }

            byte[] bytes = IOUtils.toByteArray(this.tis);
            this.tis.getNextTarEntry();
            return bytes;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException("Cannot remove with this iterator.");
    }

    /* (non-Javadoc)
     * @see java.lang.AutoCloseable#close()
     */
    @Override
    public void close() throws IOException {
        this.tis.close();
    }
}