Back to index...

	/*
	* Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.awt;

	import java.io.File;
	import java.io.IOException;
	import java.net.URISyntaxException;
	import java.net.URI;
	import java.net.URL;
	import java.net.MalformedURLException;
	import java.awt.AWTPermission;
	import java.awt.GraphicsEnvironment;
	import java.awt.HeadlessException;
	import java.awt.peer.DesktopPeer;
	import sun.awt.SunToolkit;
	import sun.awt.HeadlessToolkit;
	import java.io.FilePermission;
	import sun.security.util.SecurityConstants;

	/**
	* The {@code Desktop} class allows a Java application to launch
	* associated applications registered on the native desktop to handle
	* a {@link java.net.URI} or a file.
	*
	* <p> Supported operations include:
	* <ul>
	* <li>launching the user-default browser to show a specified
	* URI;</li>
	* <li>launching the user-default mail client with an optional
	* {@code mailto} URI;</li>
	* <li>launching a registered application to open, edit or print a
	* specified file.</li>
	* </ul>
	*
	* <p> This class provides methods corresponding to these
	* operations. The methods look for the associated application
	* registered on the current platform, and launch it to handle a URI
	* or file. If there is no associated application or the associated
	* application fails to be launched, an exception is thrown.
	*
	* <p> An application is registered to a URI or file type; for
	* example, the {@code "sxi"} file extension is typically registered
	* to StarOffice. The mechanism of registering, accessing, and
	* launching the associated application is platform-dependent.
	*
	* <p> Each operation is an action type represented by the {@link
	* Desktop.Action} class.
	*
	* <p> Note: when some action is invoked and the associated
	* application is executed, it will be executed on the same system as
	* the one on which the Java application was launched.
	*
	* @since 1.6
	* @author Armin Chen
	* @author George Zhang
	*/
	public class Desktop {

	/**
	* Represents an action type. Each platform supports a different
	* set of actions. You may use the {@link Desktop#isSupported}
	* method to determine if the given action is supported by the
	* current platform.
	* @see java.awt.Desktop#isSupported(java.awt.Desktop.Action)
	* @since 1.6
	*/
	public static enum Action {
	/**
	* Represents an "open" action.
	* @see Desktop#open(java.io.File)
	*/
	OPEN,
	/**
	* Represents an "edit" action.
	* @see Desktop#edit(java.io.File)
	*/
	EDIT,
	/**
	* Represents a "print" action.
	* @see Desktop#print(java.io.File)
	*/
	PRINT,
	/**
	* Represents a "mail" action.
	* @see Desktop#mail()
	* @see Desktop#mail(java.net.URI)
	*/
	MAIL,
	/**
	* Represents a "browse" action.
	* @see Desktop#browse(java.net.URI)
	*/
	BROWSE
	};

	private DesktopPeer peer;

	/**
	* Suppresses default constructor for noninstantiability.
	*/
	private Desktop() {
	peer = Toolkit.getDefaultToolkit().createDesktopPeer(this);
	}

	/**
	* Returns the <code>Desktop</code> instance of the current
	* browser context. On some platforms the Desktop API may not be
	* supported; use the {@link #isDesktopSupported} method to
	* determine if the current desktop is supported.
	* @return the Desktop instance of the current browser context
	* @throws HeadlessException if {@link
	* GraphicsEnvironment#isHeadless()} returns {@code true}
	* @throws UnsupportedOperationException if this class is not
	* supported on the current platform
	* @see #isDesktopSupported()
	* @see java.awt.GraphicsEnvironment#isHeadless
	*/
	public static synchronized Desktop getDesktop(){
	if (GraphicsEnvironment.isHeadless()) throw new HeadlessException();
	if (!Desktop.isDesktopSupported()) {
	throw new UnsupportedOperationException("Desktop API is not " +
	"supported on the current platform");
	}

	sun.awt.AppContext context = sun.awt.AppContext.getAppContext();
	Desktop desktop = (Desktop)context.get(Desktop.class);

	if (desktop == null) {
	desktop = new Desktop();
	context.put(Desktop.class, desktop);
	}

	return desktop;
	}

	/**
	* Tests whether this class is supported on the current platform.
	* If it's supported, use {@link #getDesktop()} to retrieve an
	* instance.
	*
	* @return <code>true</code> if this class is supported on the
	* current platform; <code>false</code> otherwise
	* @see #getDesktop()
	*/
	public static boolean isDesktopSupported(){
	Toolkit defaultToolkit = Toolkit.getDefaultToolkit();
	if (defaultToolkit instanceof SunToolkit) {
	return ((SunToolkit)defaultToolkit).isDesktopSupported();
	}
	return false;
	}

	/**
	* Tests whether an action is supported on the current platform.
	*
	* <p>Even when the platform supports an action, a file or URI may
	* not have a registered application for the action. For example,
	* most of the platforms support the {@link Desktop.Action#OPEN}
	* action. But for a specific file, there may not be an
	* application registered to open it. In this case, {@link
	* #isSupported} may return {@code true}, but the corresponding
	* action method will throw an {@link IOException}.
	*
	* @param action the specified {@link Action}
	* @return <code>true</code> if the specified action is supported on
	* the current platform; <code>false</code> otherwise
	* @see Desktop.Action
	*/
	public boolean isSupported(Action action) {
	return peer.isSupported(action);
	}

	/**
	* Checks if the file is a valid file and readable.
	*
	* @throws SecurityException If a security manager exists and its
	* {@link SecurityManager#checkRead(java.lang.String)} method
	* denies read access to the file
	* @throws NullPointerException if file is null
	* @throws IllegalArgumentException if file doesn't exist
	*/
	private static void checkFileValidation(File file) {
	if (!file.exists()) {
	throw new IllegalArgumentException("The file: "
	+ file.getPath() + " doesn't exist.");
	}
	}

	/**
	* Checks if the action type is supported.
	*
	* @param actionType the action type in question
	* @throws UnsupportedOperationException if the specified action type is not
	* supported on the current platform
	*/
	private void checkActionSupport(Action actionType){
	if (!isSupported(actionType)) {
	throw new UnsupportedOperationException("The " + actionType.name()
	+ " action is not supported on the current platform!");
	}
	}


	/**
	* Calls to the security manager's <code>checkPermission</code> method with
	* an <code>AWTPermission("showWindowWithoutWarningBanner")</code>
	* permission.
	*/
	private void checkAWTPermission(){
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	sm.checkPermission(new AWTPermission(
	"showWindowWithoutWarningBanner"));
	}
	}

	/**
	* Launches the associated application to open the file.
	*
	* <p> If the specified file is a directory, the file manager of
	* the current platform is launched to open it.
	*
	* @param file the file to be opened with the associated application
	* @throws NullPointerException if {@code file} is {@code null}
	* @throws IllegalArgumentException if the specified file doesn't
	* exist
	* @throws UnsupportedOperationException if the current platform
	* does not support the {@link Desktop.Action#OPEN} action
	* @throws IOException if the specified file has no associated
	* application or the associated application fails to be launched
	* @throws SecurityException if a security manager exists and its
	* {@link java.lang.SecurityManager#checkRead(java.lang.String)}
	* method denies read access to the file, or it denies the
	* <code>AWTPermission("showWindowWithoutWarningBanner")</code>
	* permission, or the calling thread is not allowed to create a
	* subprocess
	* @see java.awt.AWTPermission
	*/
	public void open(File file) throws IOException {
	file = new File(file.getPath());
	checkAWTPermission();
	checkExec();
	checkActionSupport(Action.OPEN);
	checkFileValidation(file);

	peer.open(file);
	}

	/**
	* Launches the associated editor application and opens a file for
	* editing.
	*
	* @param file the file to be opened for editing
	* @throws NullPointerException if the specified file is {@code null}
	* @throws IllegalArgumentException if the specified file doesn't
	* exist
	* @throws UnsupportedOperationException if the current platform
	* does not support the {@link Desktop.Action#EDIT} action
	* @throws IOException if the specified file has no associated
	* editor, or the associated application fails to be launched
	* @throws SecurityException if a security manager exists and its
	* {@link java.lang.SecurityManager#checkRead(java.lang.String)}
	* method denies read access to the file, or {@link
	* java.lang.SecurityManager#checkWrite(java.lang.String)} method
	* denies write access to the file, or it denies the
	* <code>AWTPermission("showWindowWithoutWarningBanner")</code>
	* permission, or the calling thread is not allowed to create a
	* subprocess
	* @see java.awt.AWTPermission
	*/
	public void edit(File file) throws IOException {
	file = new File(file.getPath());
	checkAWTPermission();
	checkExec();
	checkActionSupport(Action.EDIT);
	file.canWrite();
	checkFileValidation(file);

	peer.edit(file);
	}

	/**
	* Prints a file with the native desktop printing facility, using
	* the associated application's print command.
	*
	* @param file the file to be printed
	* @throws NullPointerException if the specified file is {@code
	* null}
	* @throws IllegalArgumentException if the specified file doesn't
	* exist
	* @throws UnsupportedOperationException if the current platform
	* does not support the {@link Desktop.Action#PRINT} action
	* @throws IOException if the specified file has no associated
	* application that can be used to print it
	* @throws SecurityException if a security manager exists and its
	* {@link java.lang.SecurityManager#checkRead(java.lang.String)}
	* method denies read access to the file, or its {@link
	* java.lang.SecurityManager#checkPrintJobAccess()} method denies
	* the permission to print the file, or the calling thread is not
	* allowed to create a subprocess
	*/
	public void print(File file) throws IOException {
	file = new File(file.getPath());
	checkExec();
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	sm.checkPrintJobAccess();
	}
	checkActionSupport(Action.PRINT);
	checkFileValidation(file);

	peer.print(file);
	}

	/**
	* Launches the default browser to display a {@code URI}.
	* If the default browser is not able to handle the specified
	* {@code URI}, the application registered for handling
	* {@code URIs} of the specified type is invoked. The application
	* is determined from the protocol and path of the {@code URI}, as
	* defined by the {@code URI} class.
	* <p>
	* If the calling thread does not have the necessary permissions,
	* and this is invoked from within an applet,
	* {@code AppletContext.showDocument()} is used. Similarly, if the calling
	* does not have the necessary permissions, and this is invoked from within
	* a Java Web Started application, {@code BasicService.showDocument()}
	* is used.
	*
	* @param uri the URI to be displayed in the user default browser
	* @throws NullPointerException if {@code uri} is {@code null}
	* @throws UnsupportedOperationException if the current platform
	* does not support the {@link Desktop.Action#BROWSE} action
	* @throws IOException if the user default browser is not found,
	* or it fails to be launched, or the default handler application
	* failed to be launched
	* @throws SecurityException if a security manager exists and it
	* denies the
	* <code>AWTPermission("showWindowWithoutWarningBanner")</code>
	* permission, or the calling thread is not allowed to create a
	* subprocess; and not invoked from within an applet or Java Web Started
	* application
	* @throws IllegalArgumentException if the necessary permissions
	* are not available and the URI can not be converted to a {@code URL}
	* @see java.net.URI
	* @see java.awt.AWTPermission
	* @see java.applet.AppletContext
	*/
	public void browse(URI uri) throws IOException {
	SecurityException securityException = null;
	try {
	checkAWTPermission();
	checkExec();
	} catch (SecurityException e) {
	securityException = e;
	}
	checkActionSupport(Action.BROWSE);
	if (uri == null) {
	throw new NullPointerException();
	}
	if (securityException == null) {
	peer.browse(uri);
	return;
	}

	// Calling thread doesn't have necessary priviledges.
	// Delegate to DesktopBrowse so that it can work in
	// applet/webstart.
	URL url = null;
	try {
	url = uri.toURL();
	} catch (MalformedURLException e) {
	throw new IllegalArgumentException("Unable to convert URI to URL", e);
	}
	sun.awt.DesktopBrowse db = sun.awt.DesktopBrowse.getInstance();
	if (db == null) {
	// Not in webstart/applet, throw the exception.
	throw securityException;
	}
	db.browse(url);
	}

	/**
	* Launches the mail composing window of the user default mail
	* client.
	*
	* @throws UnsupportedOperationException if the current platform
	* does not support the {@link Desktop.Action#MAIL} action
	* @throws IOException if the user default mail client is not
	* found, or it fails to be launched
	* @throws SecurityException if a security manager exists and it
	* denies the
	* <code>AWTPermission("showWindowWithoutWarningBanner")</code>
	* permission, or the calling thread is not allowed to create a
	* subprocess
	* @see java.awt.AWTPermission
	*/
	public void mail() throws IOException {
	checkAWTPermission();
	checkExec();
	checkActionSupport(Action.MAIL);
	URI mailtoURI = null;
	try{
	mailtoURI = new URI("mailto:?");
	peer.mail(mailtoURI);
	} catch (URISyntaxException e){
	// won't reach here.
	}
	}

	/**
	* Launches the mail composing window of the user default mail
	* client, filling the message fields specified by a {@code
	* mailto:} URI.
	*
	* <p> A <code>mailto:</code> URI can specify message fields
	* including <i>"to"</i>, <i>"cc"</i>, <i>"subject"</i>,
	* <i>"body"</i>, etc. See <a
	* href="http://www.ietf.org/rfc/rfc2368.txt">The mailto URL
	* scheme (RFC 2368)</a> for the {@code mailto:} URI specification
	* details.
	*
	* @param mailtoURI the specified {@code mailto:} URI
	* @throws NullPointerException if the specified URI is {@code
	* null}
	* @throws IllegalArgumentException if the URI scheme is not
	* <code>"mailto"</code>
	* @throws UnsupportedOperationException if the current platform
	* does not support the {@link Desktop.Action#MAIL} action
	* @throws IOException if the user default mail client is not
	* found or fails to be launched
	* @throws SecurityException if a security manager exists and it
	* denies the
	* <code>AWTPermission("showWindowWithoutWarningBanner")</code>
	* permission, or the calling thread is not allowed to create a
	* subprocess
	* @see java.net.URI
	* @see java.awt.AWTPermission
	*/
	public void mail(URI mailtoURI) throws IOException {
	checkAWTPermission();
	checkExec();
	checkActionSupport(Action.MAIL);
	if (mailtoURI == null) throw new NullPointerException();

	if (!"mailto".equalsIgnoreCase(mailtoURI.getScheme())) {
	throw new IllegalArgumentException("URI scheme is not \"mailto\"");
	}

	peer.mail(mailtoURI);
	}

	private void checkExec() throws SecurityException {
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	sm.checkPermission(new FilePermission("<<ALL FILES>>",
	SecurityConstants.FILE_EXECUTE_ACTION));
	}
	}
	}

Back to index...