UnpackResourceZip.java

package hudson.plugins.jobConfigHistory;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.commons.io.IOUtils;
import org.junit.rules.ExternalResource;
import org.junit.rules.TemporaryFolder;

/**
 * Takes the URL of zip with test resources and unpacks it to a temporary
 * folder, which may be retrieved with {@link UnpackResourceZip#getRoot()}.
 *
 * @author Mirko Friedenhagen
 */
public class UnpackResourceZip extends ExternalResource {

	private final TemporaryFolder temporaryFolder = new TemporaryFolder(
			new File("target"));

	private final URL resourceURL;

	public static UnpackResourceZip create() {
		return new UnpackResourceZip(UnpackResourceZip.class
				.getResource("JobConfigHistoryPurgerIT.zip"));
	}

	public UnpackResourceZip(URL resourceURL) {
		this.resourceURL = resourceURL;
	}

	@Override
	protected void before() throws Throwable {
		temporaryFolder.create();
		unpackZip();
	}

	@Override
	protected void after() {
		temporaryFolder.delete();
	}

	/**
	 * @return the root location of the unpacked resources.
	 */
	public File getRoot() {
		return temporaryFolder.getRoot();
	}

	/**
	 * @param resourceName
	 *            name
	 * @return an unpacked resource.
	 */
	public File getResource(final String resourceName) {
		return new File(getRoot(), resourceName);
	}

	private void unpackZip() throws IOException {
		// IOUtils.copy below buffers InputStream!
		final ZipInputStream in = new ZipInputStream(resourceURL.openStream());
		try {
			ZipEntry entry = in.getNextEntry();
			while (entry != null) {
				final File file = new File(temporaryFolder.getRoot(),
						entry.getName());
				if (!entry.isDirectory()) {
					createFileResource(file, in);
				} else {
					createDirectoryResource(file);
				}
				entry = in.getNextEntry();
			}
		} finally {
			in.close();
		}
	}

	private void createFileResource(final File file, final ZipInputStream in)
			throws FileNotFoundException, IOException {
		createDirectoryResource(file.getParentFile());
		final BufferedOutputStream out = new BufferedOutputStream(
				new FileOutputStream(file));
		try {
			IOUtils.copy(in, out);
		} finally {
			out.close();
		}
	}

	private void createDirectoryResource(final File file) {
		file.mkdirs();
	}
}