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Eclipse Platform
Release 3.5

org.eclipse.ui
Class Saveable

java.lang.Object
  extended by org.eclipse.ui.internal.InternalSaveable
      extended by 
org.eclipse.ui.Saveable
All Implemented Interfaces:
IAdaptable
Direct Known Subclasses:
AbstractTextEditor.TextEditorSavable, SaveableComparison

public abstract class Saveable
extends org.eclipse.ui.internal.InternalSaveable
implements IAdaptable

A Saveable represents a unit of saveability, e.g. an editable subset of the underlying domain model that may contain unsaved changes. Different workbench parts (editors and views) may present the same saveables in different ways. This interface allows the workbench to provide more appropriate handling of operations such as saving and closing workbench parts. For example, if two editors sharing the same saveable with unsaved changes are closed simultaneously, the user is only prompted to save the changes once for the shared saveable, rather than once for each editor.

Workbench parts that work in terms of saveables should implement ISaveablesSource.

Since:
3.2
See Also:
ISaveablesSource

Constructor Summary
Saveable ()
           
 
Method Summary
 void disableUI ( IWorkbenchPart[] parts, boolean closing)
          Disables the UI of the given parts containing this saveable if necessary.
abstract  void doSave ( IProgressMonitor monitor)
          Saves the contents of this saveable.
  IJobRunnable doSave ( IProgressMonitor monitor, IShellProvider shellProvider)
          Saves this saveable, or prepares this saveable for a background save operation.
 void enableUI ( IWorkbenchPart[] parts)
          Enables the UI of the given parts containing this saveable after a background save operation has finished.
abstract  boolean equals ( Object object)
          Clients must implement equals and hashCode as defined in Object.equals(Object) and Object.hashCode() .
  Object getAdapter ( Class adapter)
          This implementation of IAdaptable.getAdapter(Class) returns null.
abstract   ImageDescriptor getImageDescriptor ()
          Returns the image descriptor for this saveable.
abstract   String getName ()
          Returns the name of this saveable for display purposes.
abstract   String getToolTipText ()
          Returns the tool tip text for this saveable.
abstract  int hashCode ()
          Clients must implement equals and hashCode as defined in Object.equals(Object) and Object.hashCode() .
abstract  boolean isDirty ()
          Returns whether the contents of this saveable have changed since the last save operation.
 boolean show ( IWorkbenchPage page)
          Attempts to show this saveable in the given page and returns true on success.
 
Methods inherited from class java.lang. Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Saveable

public Saveable()
Method Detail

show

public boolean show(
IWorkbenchPage page)
Attempts to show this saveable in the given page and returns true on success. The default implementation does nothing and returns false.

Parameters:
page - the workbench page in which to show this saveable
Returns:
true if this saveable is now visible to the user
Since:
3.3

getName

public abstract 
String getName()
Returns the name of this saveable for display purposes.

Returns:
the model's name; never null.

getToolTipText

public abstract 
String getToolTipText()
Returns the tool tip text for this saveable. This text is used to differentiate between two inputs with the same name. For instance, MyClass.java in folder X and MyClass.java in folder Y. The format of the text varies between input types.

Returns:
the tool tip text; never null

getImageDescriptor

public abstract 
ImageDescriptor getImageDescriptor()
Returns the image descriptor for this saveable.

Returns:
the image descriptor for this model; may be null if there is no image

doSave

public abstract void doSave(
IProgressMonitor monitor)
                     throws 
CoreException
Saves the contents of this saveable.

If the save is cancelled through user action, or for any other reason, the part should invoke setCancelled on the IProgressMonitor to inform the caller.

This method is long-running; progress and cancellation are provided by the given progress monitor.

Parameters:
monitor - the progress monitor
Throws:
CoreException - if the save fails; it is the caller's responsibility to report the failure to the user

isDirty

public abstract boolean isDirty()
Returns whether the contents of this saveable have changed since the last save operation.

Note: this method is called frequently, for example by actions to determine their enabled status.

Returns:
true if the contents have been modified and need saving, and false if they have not changed since the last save

equals

public abstract boolean equals(
Object object)
Clients must implement equals and hashCode as defined in Object.equals(Object) and Object.hashCode() . Two saveables should be equal if their dirty state is shared, and saving one will save the other. If two saveables are equal, their names, tooltips, and images should be the same because only one of them will be shown when prompting the user to save.

Overrides:
equals in class Object
Parameters:
object -
Returns:
true if this Saveable is equal to the given object

hashCode

public abstract int hashCode()
Clients must implement equals and hashCode as defined in Object.equals(Object) and Object.hashCode() . Two saveables should be equal if their dirty state is shared, and saving one will save the other. If two saveables are equal, their hash codes MUST be the same, and their names, tooltips, and images should be the same because only one of them will be shown when prompting the user to save.

IMPORTANT: Implementers should ensure that the hashCode returned is sufficiently unique so as not to collide with hashCodes returned by other implementations. It is suggested that the defining plug-in's ID be used as part of the returned hashCode, as in the following example:

     int PRIME = 31;
     int hash = ...; // compute the "normal" hash code, e.g. based on some identifier unique within the defining plug-in
     return hash * PRIME + MY_PLUGIN_ID.hashCode();
 

Overrides:
hashCode in class Object
Returns:
a hash code

doSave

public 
IJobRunnable doSave(
IProgressMonitor monitor,
                           
IShellProvider shellProvider)
                    throws 
CoreException
Saves this saveable, or prepares this saveable for a background save operation. Returns null if this saveable has been successfully saved, or a job runnable that needs to be run to complete the save in the background. This method is called in the UI thread. If this saveable supports saving in the background, it should do only minimal work. However, since the job runnable returned by this method (if any) will not run on the UI thread, this method should copy any state that can only be accessed from the UI thread so that the job runnable will be able to access it.

The supplied shell provider can be used from within this method and from within the job runnable for the purpose of parenting dialogs. Care should be taken not to open dialogs gratuitously and only if user input is required for cases where the save cannot otherwise proceed - note that in any given save operation, many saveable objects may be saved at the same time. In particular, errors should be signaled by throwing an exception, or if an error occurs while running the job runnable, an error status should be returned.

If the foreground part of the save is cancelled through user action, or for any other reason, the part should invoke setCancelled on the IProgressMonitor to inform the caller. If the background part of the save is cancelled, the job should return a IStatus.CANCEL status.

This method is long-running; progress and cancellation are provided by the given progress monitor.

The default implementation of this method calls doSave(IProgressMonitor) and returns null.

Parameters:
monitor - a progress monitor used for reporting progress and cancellation
shellProvider - an object that can provide a shell for parenting dialogs
Returns:
null if this saveable has been saved successfully, or a job runnable that needs to be run to complete the save in the background.
Throws:
CoreException - if the save fails; it is the caller's responsibility to report the failure to the user
Since:
3.3

disableUI

public void disableUI(
IWorkbenchPart[] parts,
                      boolean closing)
Disables the UI of the given parts containing this saveable if necessary. This method is not intended to be called by clients. A corresponding call to

Saveables that can be saved in the background should ensure that the user cannot make changes to their data from the UI, for example by disabling controls, unless they are prepared to handle this case. This method is called on the UI thread after a job runnable has been returned from doSave(IProgressMonitor, IShellProvider) and before spinning the event loop. The closing flag indicates that this saveable is currently being saved in response to closing a workbench part, in which case further changes to this saveable through the UI must be prevented.

The default implementation calls setEnabled(false) on the given parts' composites.

Parameters:
parts - the workbench parts containing this saveable
closing - a boolean flag indicating whether the save was triggered by a request to close a workbench part, and all of the given parts will be closed after the save operation finishes successfully.
Since:
3.3

enableUI

public void enableUI(
IWorkbenchPart[] parts)
Enables the UI of the given parts containing this saveable after a background save operation has finished. This method is not intended to be called by clients.

The default implementation calls setEnabled(true) on the given parts' composites.

Parameters:
parts - the workbench parts containing this saveable
Since:
3.3

getAdapter

public 
Object getAdapter(
Class adapter)
This implementation of IAdaptable.getAdapter(Class) returns null. Subclasses may override. This allows two unrelated subclasses of Saveable to implement equals(Object) and hashCode() based on an underlying implementation class that is shared by both Saveable subclasses.

Specified by:
getAdapter in interface IAdaptable
Parameters:
adapter - the adapter class to look up
Returns:
a object castable to the given class, or null if this object does not have an adapter for the given class
Since:
3.3

Eclipse Platform
Release 3.5

Guidelines for using Eclipse APIs.

Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.


 
 
  Published under the terms of the Eclipse Public License Version 1.0 ("EPL") Design by Interspire