FileTypeFactory.java from Magellan-Client at Krugle

Show FileTypeFactory.java syntax highlighted

/*
 *  Copyright (C) 2000-2004 Roger Butenuth, Andreas Gampe,
 *                          Stefan Goetz, Sebastian Pappert,
 *                          Klaas Prause, Enno Rehling,
 *                          Sebastian Tusk, Ulrich Kuester,
 *                          Ilja Pavkovic
 *
 * This file is part of the Eressea Java Code Base, see the
 * file LICENSING for the licensing information applying to
 * this file.
 *
 */

package com.eressea.io.file;

import java.io.File;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * A class to create FileTypes.
 */
public class FileTypeFactory {
	private FileTypeFactory() {
	}

	private static FileTypeFactory singleton = new FileTypeFactory();

	/**
	 * Returns the sole FileTypeFactory (with respect to singleton pattern).
	 *
	 * @return the singleton <code>FileTypeFactory</code>
	 */
	public static FileTypeFactory singleton() {
		return singleton;
	}

	/**
	 * Creates an <code>InputStreamSourceFileType</code> of the given file name.
	 *
	 * @param url the URL to the InputStream
	 *
	 * @return an InputStreamSourceFileType pointing to the given URL.
	 *
	 * @throws IOException
	 */
	public FileType createInputStreamSourceFileType(File url) throws IOException {
		return new InputStreamSourceFileType(url).checkConnection();
	}

	/**
	 * Creates an <code>InputStreamSourceFileType</code> of the given file name.
	 *
	 * @param fileName the URL to the InputStream
	 * @param readonly file shall be readonly
	 *
	 * @return a FileType pointing to the given File.
	 *
	 * @throws IOException
	 */
	public FileType createFileType(File fileName, boolean readonly) throws IOException {
		return createFileType(fileName, readonly, null);
	}

	/**
	 * Creates an <code>InputStreamSourceFileType</code> of the given file name.
	 *
	 * @param fileName the URL to the InputStream
	 * @param readonly file shall be readonly
	 * @param ftc a FileTypeChooser used if entry in compressed file is not unique.
	 *
	 * @return a FileType pointing to the given File.
	 *
	 * @throws IOException
	 */
	public FileType createFileType(File fileName, boolean readonly, FileTypeChooser ftc)
							throws IOException
	{
		return doCreateFileType(fileName, readonly, ftc).checkConnection();
	}

	private FileType doCreateFileType(File fileName, boolean readonly, FileTypeChooser ftc)
							   throws IOException
	{
		if(fileName == null) {
			throw new NullPointerException();
		}

		String fileNameLC = fileName.getName().toLowerCase();

		if(fileNameLC.endsWith(FileType.GZIP)) {
			return new GZipFileType(fileName, readonly);
		}

		if(fileNameLC.endsWith(FileType.BZIP2)) {
			return new BZip2FileType(fileName, readonly);
		}

		if(fileNameLC.endsWith(FileType.ZIP)) {
			return createZipFileType(fileName, readonly, ftc);
		}

		if(fileNameLC.endsWith(FileType.CR) || fileNameLC.endsWith(FileType.XML)) {
            return new FileType(fileName, readonly);
        }

		return new UnknownFileType(fileName, readonly);
	}

	private static final String ENDINGS[] = new String[] { FileType.CR, FileType.XML };

	protected FileType createZipFileType(File fileName, boolean readonly, FileTypeChooser ftc)
								  throws IOException
	{
		ZipFile zFile = new ZipFile(fileName);

		ZipEntry entries[] = ZipFileType.getZipEntries(zFile, ENDINGS);

		if(entries.length == 0) {
			throw new NoValidEntryException();
		}

		if(entries.length == 1) {
			return new ZipFileType(fileName, readonly, entries[0]);
		}

		// entries > 1, so we need to choose one
		if(ftc == null) {
			throw new NotUniqueEntryException();
		}

		ZipEntry chosenEntry = ftc.chooseZipEntry(entries);

		if(chosenEntry == null) {
			throw new NotUniqueEntryException();
		}

		return new ZipFileType(fileName, readonly, chosenEntry);
	}

	/**
	 * A <code>FileTypeChooser</code> selects single entry if multiple valid entries are found in a
	 * compressed file, e.g. multiple .cr files in a .zip file.
	 */
	public static class FileTypeChooser {
		/**
		 * Selects a <code>ZipEntry</code>.
		 *
		 * @param entries an array of ZipEntry objects
		 *
		 * @return the selected ZipEntry or <code>null</code> if none  have been selected.
		 */
		public ZipEntry chooseZipEntry(ZipEntry entries[]) {
			return null;
		}
	}

	/**
	 * A <code>NotUniqueEntryException</code> shall be thrown if  there are multiple valid entries
	 * in a compressed file and  none have been selected.
	 */
	public static class NotUniqueEntryException extends IOException {
	}

	/**
	 * A <code>NotValidEntryException</code> shall be thrown if  there is no valid entry in a
	 * compressed file.
	 */
	public static class NoValidEntryException extends IOException {
	}
}
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