org.eclipse.mdm.api.base/src/main/java/org/eclipse/mdm/api/base/model/FileLink.java - mdmbl/org.eclipse.mdm - Git at Google

 /********************************************************************************
  * Copyright (c) 2015-2020 Contributors to the Eclipse Foundation
  *
  * See the NOTICE file(s) distributed with this work for additional
  * information regarding copyright ownership.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0.
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  ********************************************************************************/

 package org.eclipse.mdm.api.base.model;

 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;

 /**
  * Utility class to manage links to externally stored files (local/remote).
  *
  * @since 1.0.0
  * @author Viktor Stoehr, Gigatronik Ingolstadt GmbH
  */
 public final class FileLink {

 	// ======================================================================
 	// Instance variables
 	// ======================================================================

 	private final State state;

 	private String remotePath;
 	private MimeType mimeType;
 	private String description;

 	private InputStream localStream;
 	private String localFileName;

 	private long size = -1;

 	// ======================================================================
 	// Constructors
 	// ======================================================================

 	/**
 	 * Constructor.
 	 *
 	 * @param fileLink Will be copied.
 	 */
 	FileLink(FileLink fileLink) {
 		remotePath = fileLink.remotePath;
 		mimeType = fileLink.mimeType;
 		description = fileLink.description;
 		localStream = fileLink.localStream;
 		size = fileLink.size;
 		state = fileLink.state;
 	}

 	/**
 	 * Constructor.
 	 *
 	 * @param remotePath The remote path.
 	 * @param mimeType   The MIME type of the linked file.
 	 */
 	private FileLink(String remotePath, MimeType mimeType) {
 		this.remotePath = remotePath;
 		this.mimeType = mimeType;

 		state = State.REMOTE;
 	}

 	/**
 	 * Constructor.
 	 *
 	 * @param localPath The local {@link Path}.
 	 * @throws IOException Thrown in case of errors.
 	 */
 	private FileLink(InputStream localStream, String name, long size, MimeType mimeType, String description) throws IOException {
 		this.localStream = localStream;
 		this.mimeType = mimeType == null ? new MimeType("application/octet-stream") : mimeType;
 		this.size = size;
 		this.localFileName = name;
 		this.description = description;
 		state = State.LOCAL;
 	}

 	// ======================================================================
 	// Public methods
 	// ======================================================================

 	/**
 	 * Creates a new {@link FileLink} instance which remotely available.
 	 *
 	 * @param remotePath  The remote path.
 	 * @param mimeType    The MIME type.
 	 * @param description Description of the file.
 	 * @return The created {@code FileLink} instance is returned.
 	 */
 	public static FileLink newRemote(String remotePath, MimeType mimeType, String description) {
 		FileLink fileLink = new FileLink(remotePath, mimeType);
 		fileLink.setDescription(description);
 		return fileLink;
 	}

 	/**
 	 * Creates a new {@link FileLink} instance which locally available.
 	 *
 	 * @param localPath The local {@link Path} to the file.
 	 * @return The created {@code FileLink} instance is returned.
 	 * @throws IOException Thrown if unable to access file with given {@code
 	 * 		Path}       .
 	 */
 	public static FileLink newLocal(InputStream localStream, String name, long size, MimeType mimeType, String description) throws IOException {
 		return new FileLink(localStream, name, size, mimeType, description);
 	}

 	public static FileLink newLocal(Path localPath) throws IOException {
 		if (Files.isDirectory(localPath)) {
 			throw new IllegalArgumentException("Local path is a directory.");
 		} else if (!Files.exists(localPath)) {
 			throw new IllegalArgumentException("Local path does not exist.");
 		} else if (!Files.isReadable(localPath)) {
 			throw new IllegalArgumentException("Local path is not readable.");
 		}

 		InputStream localStream = Files.newInputStream(localPath);
 		long size = Files.size(localPath);
 		String name = localPath.getFileName().toString();
 		String mimeType = Files.probeContentType(localPath);
 		MimeType mimeT = mimeType == null ? null : new MimeType(mimeType);
 		return new FileLink(localStream, name, size, mimeT, name);
 	}

 	/**
 	 * Returns the name of the linked file.
 	 *
 	 * @return Name of the file is returned.
 	 * @throws IllegalStateException Thrown if unable to retrieve the file name.
 	 */
 	public String getFileName() {
 		Path fileNamePath = null;
 		String fileName = null;
 		if (isLocal()) {
 			fileName = this.localFileName;
 		} else if (isRemote()) {
 			try {
 				// on Windows, Paths.get() cannot handle file urls in the form
 				// file://REMOTE_HOST/path/filename
 				String fixedPath = remotePath.replaceFirst("file:", "");
 				fileNamePath = Paths.get(URLDecoder.decode(fixedPath, StandardCharsets.UTF_8.name())).getFileName();
 			} catch (UnsupportedEncodingException e) {
 				throw new IllegalStateException("Unable to decode remote path due to: " + e.getMessage(), e);
 			}

 			if (fileNamePath == null) {
 				throw new IllegalStateException("File name is unknown.");
 			}
 			fileName = fileNamePath.toString();
 		}

 		return fileName;
 	}

 	/**
 	 * Returns the MIME type of the linked file.
 	 *
 	 * @return The MIME type is returned.
 	 */
 	public MimeType getMimeType() {
 		return mimeType;
 	}

 	/**
 	 * Checks whether a local {@link Path} is available for the linked file.
 	 *
 	 * @return Returns {@code true} if a local {@code Path} is available.
 	 */
 	public boolean isLocal() {
 		return localStream != null;
 	}

 	/**
 	 * Returns the local {@link InputStream} to the linked file. Calling this method is
 	 * only allowed if calling {@link #isLocal()} returns {@code
 	 * true}.
 	 *
 	 * @return The local {@code Path} to the linked file is returned.
 	 */
 	public InputStream getLocalStream() {
 		if (isLocal()) {
 			return localStream;
 		}

 		throw new IllegalStateException("Local path is not available.");
 	}

 	/**
 	 * This method is called by API providers to set the local {@link InputStream} once the
 	 * remote file was downloaded.
 	 *
 	 * @param localPath The local {@code InputStream} of the downloaded file.
 	 * @throws IllegalStateException Thrown if this file link is 'LOCAL'.
 	 */
 	public void setLocalStream(InputStream localStream) {
 		if (State.LOCAL == state) {
 			throw new IllegalStateException("It is not allowed to replace an existing local path.");
 		}

 		this.localStream = localStream;
 	}

 	/**
 	 * Checks whether a remote path is available for for linked file.
 	 *
 	 * @return Returns {@code true} if a remote path is available.
 	 */
 	public boolean isRemote() {
 		return remotePath != null && !remotePath.isEmpty();
 	}

 	/**
 	 * Returns the remote path to the linked file. Calling this method is only
 	 * allowed if calling {@link #isRemote()} returns {@code true}.
 	 *
 	 * @return The remote path to the linked file is returned.
 	 */
 	public String getRemotePath() {
 		if (isRemote()) {
 			return remotePath;
 		}

 		throw new IllegalStateException("Remote path is not available.");
 	}

 	/**
 	 * This method is called by API providers to set the remote path once the local
 	 * file has been uploaded.
 	 *
 	 * @param remotePath The remote path of the uploaded file.
 	 * @throws IllegalStateException Thrown if this file link is 'REMOTE'.
 	 */
 	public void setRemotePath(String remotePath) {
 		if (State.REMOTE == state) {
 			throw new IllegalStateException("It is not allowed to replace an existing remote path.");
 		}
 		this.remotePath = remotePath;
 	}

 	/**
 	 * Returns the description of the linked file.
 	 *
 	 * @return The description is returned.
 	 */
 	public String getDescription() {
 		return description == null ? "" : description;
 	}

 	/**
 	 * Sets a new description for the linked file.
 	 *
 	 * @param description The new description.
 	 */
 	public void setDescription(String description) {
 		this.description = description;
 	}

 	/**
 	 * Returns the size of the linked file or {@code -1} if unknown.
 	 *
 	 * @return The file size in bytes is returned.
 	 */
 	public long getSize() {
 		return size;
 	}

 	/**
 	 * Returns the formatted file size of the linked file.
 	 *
 	 * @param format Used to format the size.
 	 * @return The formatted file size is returned.
 	 */
 	public String getSize(Format format) {
 		return format.getSize(size);
 	}

 	/**
 	 * This method is called by API providers to set the file size for the linked
 	 * file.
 	 *
 	 * @param size The size of the file in bytes.
 	 */
 	public void setFileSize(long size) {
 		this.size = size;
 	}

 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public int hashCode() {
 		if (State.LOCAL == state) {
 			if (!isLocal()) {
 				return "".hashCode();
 			}
 			return getLocalStream().hashCode();
 		}
 		if (!isRemote()) {
 			return "".hashCode();
 		}
 		return getRemotePath().hashCode();
 	}

 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public boolean equals(Object object) {
 		if (object instanceof FileLink) {
 			FileLink other = (FileLink) object;
 			if (state == other.state) {
 				if (State.LOCAL == state) {
 					if (!isLocal()) {
 						return !other.isLocal();
 					}
 					return getLocalStream().equals(other.getLocalStream());
 				}
 				if (!isRemote()) {
 					return !other.isRemote();
 				}
 				return getRemotePath().equals(other.getRemotePath());
 			}
 		}

 		return false;
 	}

 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder("FileLink(Description = ");

 		if (!getDescription().isEmpty()) {
 			sb.append(getDescription());
 		}

 		if (isLocal()) {
 			sb.append(", LocalPath = ").append(getLocalStream());
 		}

 		if (isRemote()) {
 			sb.append(", RemotePath = ").append(getRemotePath());
 		}

 		sb.append(", Size = ");
 		if (getSize() > 0) {
 			sb.append(getSize(Format.DECIMAL)).append(" / ").append(getSize(Format.BINARY));
 		} else {
 			sb.append("UNKNOWN");
 		}

 		return sb.append(')').toString();
 	}

 	// ======================================================================
 	// Package methods
 	// ======================================================================

 	/**
 	 * Checks whether given {@link FileLink} may be treated as equal. This is the
 	 * case if either their local {@link Path}s or remote paths are equal.
 	 *
 	 * @param o1 The first {@code FileLink}.
 	 * @param o2 The second {@code FileLink}.
 	 * @return Returns {@code true} if either their local {@code Path}s or remote
 	 *         paths are equal.
 	 */
 	static boolean areEqual(FileLink o1, FileLink o2) {
 		return isLocalPathEqual(o1, o2) || isRemotePathEqual(o1, o2);
 	}

 	// ======================================================================
 	// Private methods
 	// ======================================================================

 	/**
 	 * Checks whether both {@link FileLink}s return {@code true} when
 	 * {@link #isLocal()} is called and their {@link Path}s are equal.
 	 *
 	 * @param o1 The first {@code FileLink}.
 	 * @param o2 The second {@code FileLink}.
 	 * @return Returns {@code true} if both {@code FileLink}s have a local
 	 *         {@code Path} which are equal.
 	 */
 	private static boolean isLocalPathEqual(FileLink o1, FileLink o2) {
 		return o1.isLocal() && o2.isLocal() && o1.getLocalStream().equals(o2.getLocalStream());
 	}

 	/**
 	 * Checks whether both {@link FileLink}s return {@code true} when
 	 * {@link #isRemote()} is called and their remote paths are equal.
 	 *
 	 * @param o1 The first {@code FileLink}.
 	 * @param o2 The second {@code FileLink}.
 	 * @return Returns {@code true} if both {@code FileLink}s have a remote path
 	 *         which are equal.
 	 */
 	private static boolean isRemotePathEqual(FileLink o1, FileLink o2) {
 		return o1.isRemote() && o2.isRemote() && o1.getRemotePath().equals(o2.getRemotePath());
 	}

 	// ======================================================================
 	// Inner classes
 	// ======================================================================

 	/**
 	 * Used to format a number of bytes into a human readable size.
 	 */
 	public enum Format {

 		// ======================================================================
 		// Enum constants
 		// ======================================================================

 		/**
 		 * Counts 1000 bits as 1 byte, so formats 110592 to '110.6 kB'.
 		 */
 		DECIMAL(1000, "kMGTPE"),

 		/**
 		 * Counts 1024 bits as 1 byte, so formats 110592 to '108.0 KiB'.
 		 */
 		BINARY(1024, "KMGTPE");

 		// ======================================================================
 		// Inner classes
 		// ======================================================================

 		private final String prefixChars;
 		private final int unit;

 		// ======================================================================
 		// Constructors
 		// ======================================================================

 		/**
 		 * Constructor.
 		 *
 		 * @param unit        The unit.
 		 * @param prefixChars The prefix characters.
 		 */
 		private Format(int unit, String prefixChars) {
 			this.prefixChars = prefixChars;
 			this.unit = unit;
 		}

 		// ======================================================================
 		// Private methods
 		// ======================================================================

 		/**
 		 * Formats given file size in bytes into a human readable one.
 		 *
 		 * @param size The number of bytes.
 		 * @return Formatted file size is returned.
 		 */
 		private String getSize(long size) {
 			if (size < 0) {
 				return "UNKNOWN";
 			} else if (size < unit) {
 				return size + " B";
 			}

 			int exponent = (int) (Math.log(size) / Math.log(unit));
 			String prefixChar = prefixChars.charAt(exponent - 1) + (DECIMAL == this ? "" : "i");
 			return String.format("%.1f %sB", size / Math.pow(unit, exponent), prefixChar);
 		}
 	}

 	/**
 	 * Used to preserve the initial state of a {@link FileLink}.
 	 */
 	private enum State {

 		/**
 		 * {@link FileLink} was initially only remotely available.
 		 */
 		REMOTE,

 		/**
 		 * {@link FileLink} was initially only locally available.
 		 */
 		LOCAL

 	}

 }
	/********************************************************************************
	* Copyright (c) 2015-2020 Contributors to the Eclipse Foundation
	*
	* See the NOTICE file(s) distributed with this work for additional
	* information regarding copyright ownership.
	*
	* This program and the accompanying materials are made available under the
	* terms of the Eclipse Public License v. 2.0 which is available at
	* http://www.eclipse.org/legal/epl-2.0.
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	********************************************************************************/

	package org.eclipse.mdm.api.base.model;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.UnsupportedEncodingException;
	import java.net.URLDecoder;
	import java.nio.charset.StandardCharsets;
	import java.nio.file.Files;
	import java.nio.file.Path;
	import java.nio.file.Paths;

	/**
	* Utility class to manage links to externally stored files (local/remote).
	*
	* @since 1.0.0
	* @author Viktor Stoehr, Gigatronik Ingolstadt GmbH
	*/
	public final class FileLink {

	// ======================================================================
	// Instance variables
	// ======================================================================

	private final State state;

	private String remotePath;
	private MimeType mimeType;
	private String description;

	private InputStream localStream;
	private String localFileName;

	private long size = -1;

	// ======================================================================
	// Constructors
	// ======================================================================

	/**
	* Constructor.
	*
	* @param fileLink Will be copied.
	*/
	FileLink(FileLink fileLink) {
	remotePath = fileLink.remotePath;
	mimeType = fileLink.mimeType;
	description = fileLink.description;
	localStream = fileLink.localStream;
	size = fileLink.size;
	state = fileLink.state;
	}

	/**
	* Constructor.
	*
	* @param remotePath The remote path.
	* @param mimeType The MIME type of the linked file.
	*/
	private FileLink(String remotePath, MimeType mimeType) {
	this.remotePath = remotePath;
	this.mimeType = mimeType;

	state = State.REMOTE;
	}

	/**
	* Constructor.
	*
	* @param localPath The local {@link Path}.
	* @throws IOException Thrown in case of errors.
	*/
	private FileLink(InputStream localStream, String name, long size, MimeType mimeType, String description) throws IOException {
	this.localStream = localStream;
	this.mimeType = mimeType == null ? new MimeType("application/octet-stream") : mimeType;
	this.size = size;
	this.localFileName = name;
	this.description = description;
	state = State.LOCAL;
	}

	// ======================================================================
	// Public methods
	// ======================================================================

	/**
	* Creates a new {@link FileLink} instance which remotely available.
	*
	* @param remotePath The remote path.
	* @param mimeType The MIME type.
	* @param description Description of the file.
	* @return The created {@code FileLink} instance is returned.
	*/
	public static FileLink newRemote(String remotePath, MimeType mimeType, String description) {
	FileLink fileLink = new FileLink(remotePath, mimeType);
	fileLink.setDescription(description);
	return fileLink;
	}

	/**
	* Creates a new {@link FileLink} instance which locally available.
	*
	* @param localPath The local {@link Path} to the file.
	* @return The created {@code FileLink} instance is returned.
	* @throws IOException Thrown if unable to access file with given {@code
	* Path} .
	*/
	public static FileLink newLocal(InputStream localStream, String name, long size, MimeType mimeType, String description) throws IOException {
	return new FileLink(localStream, name, size, mimeType, description);
	}

	public static FileLink newLocal(Path localPath) throws IOException {
	if (Files.isDirectory(localPath)) {
	throw new IllegalArgumentException("Local path is a directory.");
	} else if (!Files.exists(localPath)) {
	throw new IllegalArgumentException("Local path does not exist.");
	} else if (!Files.isReadable(localPath)) {
	throw new IllegalArgumentException("Local path is not readable.");
	}

	InputStream localStream = Files.newInputStream(localPath);
	long size = Files.size(localPath);
	String name = localPath.getFileName().toString();
	String mimeType = Files.probeContentType(localPath);
	MimeType mimeT = mimeType == null ? null : new MimeType(mimeType);
	return new FileLink(localStream, name, size, mimeT, name);
	}

	/**
	* Returns the name of the linked file.
	*
	* @return Name of the file is returned.
	* @throws IllegalStateException Thrown if unable to retrieve the file name.
	*/
	public String getFileName() {
	Path fileNamePath = null;
	String fileName = null;
	if (isLocal()) {
	fileName = this.localFileName;
	} else if (isRemote()) {
	try {
	// on Windows, Paths.get() cannot handle file urls in the form
	// file://REMOTE_HOST/path/filename
	String fixedPath = remotePath.replaceFirst("file:", "");
	fileNamePath = Paths.get(URLDecoder.decode(fixedPath, StandardCharsets.UTF_8.name())).getFileName();
	} catch (UnsupportedEncodingException e) {
	throw new IllegalStateException("Unable to decode remote path due to: " + e.getMessage(), e);
	}

	if (fileNamePath == null) {
	throw new IllegalStateException("File name is unknown.");
	}
	fileName = fileNamePath.toString();
	}

	return fileName;
	}

	/**
	* Returns the MIME type of the linked file.
	*
	* @return The MIME type is returned.
	*/
	public MimeType getMimeType() {
	return mimeType;
	}

	/**
	* Checks whether a local {@link Path} is available for the linked file.
	*
	* @return Returns {@code true} if a local {@code Path} is available.
	*/
	public boolean isLocal() {
	return localStream != null;
	}

	/**
	* Returns the local {@link InputStream} to the linked file. Calling this method is
	* only allowed if calling {@link #isLocal()} returns {@code
	* true}.
	*
	* @return The local {@code Path} to the linked file is returned.
	*/
	public InputStream getLocalStream() {
	if (isLocal()) {
	return localStream;
	}

	throw new IllegalStateException("Local path is not available.");
	}

	/**
	* This method is called by API providers to set the local {@link InputStream} once the
	* remote file was downloaded.
	*
	* @param localPath The local {@code InputStream} of the downloaded file.
	* @throws IllegalStateException Thrown if this file link is 'LOCAL'.
	*/
	public void setLocalStream(InputStream localStream) {
	if (State.LOCAL == state) {
	throw new IllegalStateException("It is not allowed to replace an existing local path.");
	}

	this.localStream = localStream;
	}

	/**
	* Checks whether a remote path is available for for linked file.
	*
	* @return Returns {@code true} if a remote path is available.
	*/
	public boolean isRemote() {
	return remotePath != null && !remotePath.isEmpty();
	}

	/**
	* Returns the remote path to the linked file. Calling this method is only
	* allowed if calling {@link #isRemote()} returns {@code true}.
	*
	* @return The remote path to the linked file is returned.
	*/
	public String getRemotePath() {
	if (isRemote()) {
	return remotePath;
	}

	throw new IllegalStateException("Remote path is not available.");
	}

	/**
	* This method is called by API providers to set the remote path once the local
	* file has been uploaded.
	*
	* @param remotePath The remote path of the uploaded file.
	* @throws IllegalStateException Thrown if this file link is 'REMOTE'.
	*/
	public void setRemotePath(String remotePath) {
	if (State.REMOTE == state) {
	throw new IllegalStateException("It is not allowed to replace an existing remote path.");
	}
	this.remotePath = remotePath;
	}

	/**
	* Returns the description of the linked file.
	*
	* @return The description is returned.
	*/
	public String getDescription() {
	return description == null ? "" : description;
	}

	/**
	* Sets a new description for the linked file.
	*
	* @param description The new description.
	*/
	public void setDescription(String description) {
	this.description = description;
	}

	/**
	* Returns the size of the linked file or {@code -1} if unknown.
	*
	* @return The file size in bytes is returned.
	*/
	public long getSize() {
	return size;
	}

	/**
	* Returns the formatted file size of the linked file.
	*
	* @param format Used to format the size.
	* @return The formatted file size is returned.
	*/
	public String getSize(Format format) {
	return format.getSize(size);
	}

	/**
	* This method is called by API providers to set the file size for the linked
	* file.
	*
	* @param size The size of the file in bytes.
	*/
	public void setFileSize(long size) {
	this.size = size;
	}

	/**
	* {@inheritDoc}
	*/
	@Override
	public int hashCode() {
	if (State.LOCAL == state) {
	if (!isLocal()) {
	return "".hashCode();
	}
	return getLocalStream().hashCode();
	}
	if (!isRemote()) {
	return "".hashCode();
	}
	return getRemotePath().hashCode();
	}

	/**
	* {@inheritDoc}
	*/
	@Override
	public boolean equals(Object object) {
	if (object instanceof FileLink) {
	FileLink other = (FileLink) object;
	if (state == other.state) {
	if (State.LOCAL == state) {
	if (!isLocal()) {
	return !other.isLocal();
	}
	return getLocalStream().equals(other.getLocalStream());
	}
	if (!isRemote()) {
	return !other.isRemote();
	}
	return getRemotePath().equals(other.getRemotePath());
	}
	}

	return false;
	}

	/**
	* {@inheritDoc}
	*/
	@Override
	public String toString() {
	StringBuilder sb = new StringBuilder("FileLink(Description = ");

	if (!getDescription().isEmpty()) {
	sb.append(getDescription());
	}

	if (isLocal()) {
	sb.append(", LocalPath = ").append(getLocalStream());
	}

	if (isRemote()) {
	sb.append(", RemotePath = ").append(getRemotePath());
	}

	sb.append(", Size = ");
	if (getSize() > 0) {
	sb.append(getSize(Format.DECIMAL)).append(" / ").append(getSize(Format.BINARY));
	} else {
	sb.append("UNKNOWN");
	}

	return sb.append(')').toString();
	}

	// ======================================================================
	// Package methods
	// ======================================================================

	/**
	* Checks whether given {@link FileLink} may be treated as equal. This is the
	* case if either their local {@link Path}s or remote paths are equal.
	*
	* @param o1 The first {@code FileLink}.
	* @param o2 The second {@code FileLink}.
	* @return Returns {@code true} if either their local {@code Path}s or remote
	* paths are equal.
	*/
	static boolean areEqual(FileLink o1, FileLink o2) {
	return isLocalPathEqual(o1, o2) \|\| isRemotePathEqual(o1, o2);
	}

	// ======================================================================
	// Private methods
	// ======================================================================

	/**
	* Checks whether both {@link FileLink}s return {@code true} when
	* {@link #isLocal()} is called and their {@link Path}s are equal.
	*
	* @param o1 The first {@code FileLink}.
	* @param o2 The second {@code FileLink}.
	* @return Returns {@code true} if both {@code FileLink}s have a local
	* {@code Path} which are equal.
	*/
	private static boolean isLocalPathEqual(FileLink o1, FileLink o2) {
	return o1.isLocal() && o2.isLocal() && o1.getLocalStream().equals(o2.getLocalStream());
	}

	/**
	* Checks whether both {@link FileLink}s return {@code true} when
	* {@link #isRemote()} is called and their remote paths are equal.
	*
	* @param o1 The first {@code FileLink}.
	* @param o2 The second {@code FileLink}.
	* @return Returns {@code true} if both {@code FileLink}s have a remote path
	* which are equal.
	*/
	private static boolean isRemotePathEqual(FileLink o1, FileLink o2) {
	return o1.isRemote() && o2.isRemote() && o1.getRemotePath().equals(o2.getRemotePath());
	}

	// ======================================================================
	// Inner classes
	// ======================================================================

	/**
	* Used to format a number of bytes into a human readable size.
	*/
	public enum Format {

	// ======================================================================
	// Enum constants
	// ======================================================================

	/**
	* Counts 1000 bits as 1 byte, so formats 110592 to '110.6 kB'.
	*/
	DECIMAL(1000, "kMGTPE"),

	/**
	* Counts 1024 bits as 1 byte, so formats 110592 to '108.0 KiB'.
	*/
	BINARY(1024, "KMGTPE");

	// ======================================================================
	// Inner classes
	// ======================================================================

	private final String prefixChars;
	private final int unit;

	// ======================================================================
	// Constructors
	// ======================================================================

	/**
	* Constructor.
	*
	* @param unit The unit.
	* @param prefixChars The prefix characters.
	*/
	private Format(int unit, String prefixChars) {
	this.prefixChars = prefixChars;
	this.unit = unit;
	}

	// ======================================================================
	// Private methods
	// ======================================================================

	/**
	* Formats given file size in bytes into a human readable one.
	*
	* @param size The number of bytes.
	* @return Formatted file size is returned.
	*/
	private String getSize(long size) {
	if (size < 0) {
	return "UNKNOWN";
	} else if (size < unit) {
	return size + " B";
	}

	int exponent = (int) (Math.log(size) / Math.log(unit));
	String prefixChar = prefixChars.charAt(exponent - 1) + (DECIMAL == this ? "" : "i");
	return String.format("%.1f %sB", size / Math.pow(unit, exponent), prefixChar);
	}
	}

	/**
	* Used to preserve the initial state of a {@link FileLink}.
	*/
	private enum State {

	/**
	* {@link FileLink} was initially only remotely available.
	*/
	REMOTE,

	/**
	* {@link FileLink} was initially only locally available.
	*/
	LOCAL

	}

	}