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ptolemy.gui
Class GraphicalMessageHandler

java.lang.Object
 extended byptolemy.util.MessageHandler
 extended byptolemy.gui.GraphicalMessageHandler

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public class GraphicalMessageHandler

extends MessageHandler

This is a message handler that reports errors in a graphical dialog box. When an applet or application starts up, it should call setContext() to specify a component with respect to which the display window should be created. This ensures that if the application is iconified or deiconified, that the display window goes with it. If the context is not specified, then the display window is centered on the screen, but iconifying and deiconifying may not work as desired.

Note that to display a window with an error message, this graphical handler must be registered by calling MessageHandler.setMessageHandler(MessageHandler). For example:

 GraphicalMessageHandler handler = new GraphicalMessageHandler();
 GraphicalMessageHandler.setMessageHandler(handler);
 GraphicalMessageHandler.error("My error", new Exception("My Exception"));
 

If setMessageHandler() is not called, then the error() call will use the default handler and possibly display the message on standard error.

This class is based on (and contains code from) the diva GUIUtilities class.

Since:

Ptolemy II 1.0

Version:

$Id: GraphicalMessageHandler.java,v 1.54 2006年02月07日 00:46:24 cxh Exp $

Author:

Edward A. Lee, Steve Neuendorffer, John Reekie, and Elaine Cheong

Accepted Rating:

Red (reviewmoderator)

Proposed Rating:

Yellow (eal)

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Field Summary
protected static java.lang.ref.WeakReference	_context The context.

Constructor Summary

GraphicalMessageHandler()

Method Summary
protected void	_error(java.lang.String info) Show the specified error message.
protected void	_error(java.lang.String info, java.lang.Throwable throwable) Show the specified message and throwable information.
protected void	_message(java.lang.String info) Show the specified message in a modal dialog.
protected void	_warning(java.lang.String info) Show the specified message in a modal dialog.
protected void	_warning(java.lang.String info, java.lang.Throwable throwable) Show the specified message and throwable information in a modal dialog.
protected boolean	_yesNoCancelQuestion(java.lang.String question) Ask the user a yes/no/cancel question, and return true if the answer is yes.
protected boolean	_yesNoQuestion(java.lang.String question) Ask the user a yes/no question, and return true if the answer is yes.
static java.awt.Component	getContext() Get the component set by a call to setContext(), or null if none.
static void	setContext(java.awt.Component context) Set the component with respect to which the display window should be created.

Methods inherited from class ptolemy.util.MessageHandler

error, error, getMessageHandler, message, setMessageHandler, shortDescription, warning, warning, yesNoCancelQuestion, yesNoQuestion

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_context

protected static java.lang.ref.WeakReference _context

The context.

Constructor Detail

GraphicalMessageHandler

public GraphicalMessageHandler()

Method Detail

getContext

public static java.awt.Component getContext()

Get the component set by a call to setContext(), or null if none.

Returns:

The component with respect to which the display window is iconified, or null if none has been specified.

See Also:

setContext(Component)

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setContext

public static void setContext(java.awt.Component context)

Set the component with respect to which the display window should be created. This ensures that if the application is iconified or deiconified, that the display window goes with it. This is maintained in a weak reference so that the frame can be garbage collected.

Parameters:

context - The component context.

See Also:

getContext()

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_error

protected void _error(java.lang.String info)

Show the specified error message. This is deferred to execute in the swing event thread if it is called outside that thread.

Overrides:

_error in class MessageHandler

Parameters:

info - The message.

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_error

protected void _error(java.lang.String info,
 java.lang.Throwable throwable)

Show the specified message and throwable information. If the throwable is an instance of CancelException, then it is not shown. By default, only the message of the throwable is thrown. The stack trace information is only shown if the user clicks on the "Display Stack Trace" button. This is deferred to execute in the swing event thread if it is called outside that thread.

Overrides:

_error in class MessageHandler

Parameters:

info - The message.

throwable - The throwable.

See Also:

CancelException

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_message

protected void _message(java.lang.String info)

Show the specified message in a modal dialog. This is deferred to execute in the swing event thread if it is called outside that thread.

Overrides:

_message in class MessageHandler

Parameters:

info - The message.

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_warning

protected void _warning(java.lang.String info)
 throws CancelException

Show the specified message in a modal dialog. If the user clicks on the "Cancel" button, then throw an exception. This gives the user the option of not continuing the execution, something that is particularly useful if continuing execution will result in repeated warnings. NOTE: If this is called outside the swing event thread, then no cancel button is presented and no CancelException will be thrown. This is because the displaying of the message must be deferred to the swing event thread, according to the swing architecture, or we could get deadlock or rendering problems.

Overrides:

_warning in class MessageHandler

Parameters:

info - The message.

Throws:

CancelException - If the user clicks on the "Cancel" button.

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_warning

protected void _warning(java.lang.String info,
 java.lang.Throwable throwable)
 throws CancelException

Show the specified message and throwable information in a modal dialog. If the user clicks on the "Cancel" button, then throw an exception. This gives the user the option of not continuing the execution, something that is particularly useful if continuing execution will result in repeated warnings. By default, only the message of the throwable is shown. The stack trace information is only shown if the user clicks on the "Display Stack Trace" button. NOTE: If this is called outside the swing event thread, then no cancel button is presented and no CancelException will be thrown. This is because the displaying of the message must be deferred to the swing event thread, according to the swing architecture, or we could get deadlock or rendering problems.

Overrides:

_warning in class MessageHandler

Parameters:

info - The message.

throwable - The throwable.

Throws:

CancelException - If the user clicks on the "Cancel" button.

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_yesNoQuestion

protected boolean _yesNoQuestion(java.lang.String question)

Ask the user a yes/no question, and return true if the answer is yes.

Overrides:

_yesNoQuestion in class MessageHandler

Parameters:

question - The yes/no question.

Returns:

True if the answer is yes.

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_yesNoCancelQuestion

protected boolean _yesNoCancelQuestion(java.lang.String question)
 throws CancelException

Ask the user a yes/no/cancel question, and return true if the answer is yes.

Overrides:

_yesNoCancelQuestion in class MessageHandler

Parameters:

question - The yes/no/cancel question.

Returns:

True if the answer is yes.

Throws:

CancelException - If the user clicks on the "Cancel" button.

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