EVALUATION
- "The problem with this is that enums are not extensible."
this has been considered, and here is the answer from Peter von der Ah??:
------------------8<----------------------------------
"> > - is it safe to declare an enum with some set of values, and then
> > extend this set of values later, in a future release?
>
> It is intended to work that way. I will be relying on this feature
> myself in JSR 199 and a low level compiler API to be included in
> mustang.
>
> A preliminary version of JLS's chapter 13 (Binary Compatibility) says:
>
> 13.4.26 Evolution of Enums
>
> Adding or reordering constants from an enum type will not break
> compatibility with pre-existing binaries.
> If a precompiled binary attempts to access an enum constant that
> no longer exists, the client will fail at runtime with a
> NoSuchFieldError. Therefore such a change is not recommended for
> widely distributed enums.
> In all other respects, the binary compatibility rules for enums
> are identical to those for classes.
>
> I guess that the wording might change slightly, but this is considered a
> very important aspect of enums.
------------------8<----------------------------------
- ... It would be useful to programatically have access to these verbs ...
This is already integrated in 6.0, as part of the JavaBeans Activation Framework.
http://java.sun.com/products/javabeans/jaf/index.jsp. Javadoc has not been yet generated,
however the code is there, you may find it by downloading source snapshot of the latest Mustang
build from mustang.dev.java.net, see package javax.activation
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EVALUATION
The API is being developed and implemented by JDIC engineers, current contact is Armin Chen.
###@###.### 2005-04-14 11:01:29 GMT
CCC: http://ccc.sfbay/6255196
###@###.### 2005-04-14 11:01:43 GMT
As of the latest JCG meeting, we don't plan to release it in Mustang.
###@###.### 2005-05-26 12:10:19 GMT
Actually, we decided to persue this feature for Mustang. The planned API looks as follows:
package java.awt;
/**
* 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 registereing, 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
};
/**
* 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()
/**
* 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()
/**
* 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)
/**
* 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 dosen'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
/**
* 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
/**
* 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
/**
* Launches the user default browser to display a URI if this is an URI the
* browser can handle. Otherwise, launches the default handler application
* for the URI depending on the protocol and path (as defined in the
* <code>URI</code> class).
*
* @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
* @see java.net.URI
* @see java.awt.AWTPermission
*/
public void browse(URI uri) throws IOException
/**
* 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
/**
* 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
}
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###@###.### 2005-06-26 04:28:49 GMT
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