Eclipse Plug-in Developer Guide (Galileo) - IWorkbenchPart (Eclipse Platform API Specification)

A view is typically used to navigate a hierarchy of information (like the workspace), open an editor, or display properties for the active editor. Modifications made in a view are saved immediately.

An editor is typically used to edit or browse a document or input object. The input is identified using an IEditorInput. Modifications made in an editor part follow an open-save-close lifecycle model.

This interface may be implemented directly. For convenience, a base implementation is defined in WorkbenchPart.

The lifecycle of a workbench part is as follows:

When a part extension is created:
- instantiate the part
- create a part site
- call part.init(site)
When a part becomes visible in the workbench:
- add part to presentation by calling part.createControl(parent) to create actual widgets
- fire partOpened event to all listeners
When a part is activated or gets focus:
- call part.setFocus()
- fire partActivated event to all listeners
When a part is closed:
- if save is needed, do save; if it fails or is canceled return
- if part is active, deactivate part
- fire partClosed event to all listeners
- remove part from presentation; part controls are disposed as part of the SWT widget tree
- call part.dispose()

After createPartControl has been called, the implementor may safely reference the controls created. When the part is closed these controls will be disposed as part of an SWT composite. This occurs before the IWorkbenchPart.dispose method is called. If there is a need to free SWT resources the part should define a dispose listener for its own control and free those resources from the dispose listener. If the part invokes any method on the disposed SWT controls after this point an SWTError will be thrown.

The last method called on IWorkbenchPart is dispose. This signals the end of the part lifecycle.

An important point to note about this lifecycle is that following a call to init, createControl may never be called. Thus in the dispose method, implementors must not assume controls were created.

Workbench parts implement the IAdaptable interface; extensions are managed by the platform's adapter manager.

See Also:: IViewPart, IEditorPart

Field Summary

static int PROP_TITLE
          The property id for getTitle, getTitleImage and getTitleToolTip.

Method Summary

void addPropertyListener ( IPropertyListener listener)
          Adds a listener for changes to properties of this workbench part.

void createPartControl ( Composite parent)
          Creates the SWT controls for this workbench part.

void dispose ()
          Disposes of this workbench part.

IWorkbenchPartSite getSite ()
          Returns the site for this workbench part.

String getTitle ()
          Returns the title of this workbench part.

Image getTitleImage ()
          Returns the title image of this workbench part.

String getTitleToolTip ()
          Returns the title tool tip text of this workbench part.

void removePropertyListener ( IPropertyListener listener)
          Removes the given property listener from this workbench part.

void setFocus ()
          Asks this part to take focus within the workbench.

Methods inherited from interface org.eclipse.core.runtime. IAdaptable

getAdapter

Field Detail

PROP_TITLE

static final int PROP_TITLE

The property id for getTitle, getTitleImage and getTitleToolTip.

See Also:: Constant Field Values

Method Detail

addPropertyListener

void addPropertyListener(
IPropertyListener listener)

Adds a listener for changes to properties of this workbench part. Has no effect if an identical listener is already registered.

The property ids are defined in IWorkbenchPartConstants.

Parameters:: listener - a property listener

createPartControl

void createPartControl(
Composite parent)

Creates the SWT controls for this workbench part.

Clients should not call this method (the workbench calls this method when it needs to, which may be never).

For implementors this is a multi-step process:

Create one or more controls within the parent.
Set the parent layout as needed.
Register any global actions with the site's IActionBars.
Register any context menus with the site.
Register a selection provider with the site, to make it available to the workbench's ISelectionService (optional).

Parameters:: parent - the parent control

dispose

void dispose()

Disposes of this workbench part.

This is the last method called on the IWorkbenchPart. At this point the part controls (if they were ever created) have been disposed as part of an SWT composite. There is no guarantee that createPartControl() has been called, so the part controls may never have been created.

Within this method a part may release any resources, fonts, images, etc. held by this part. It is also very important to deregister all listeners from the workbench.

Clients should not call this method (the workbench calls this method at appropriate times).

getSite


IWorkbenchPartSite getSite()

Returns the site for this workbench part. The site can be null while the workbench part is being initialized. After the initialization is complete, this value must be non-null for the remainder of the part's life cycle.

Returns:: The part site; this value may be null if the part has not yet been initialized

getTitle


String getTitle()

Returns the title of this workbench part. If this value changes the part must fire a property listener event with PROP_TITLE.

The title is used to populate the title bar of this part's visual container.

Returns:: the workbench part title (not null)

getTitleImage


Image getTitleImage()

Returns the title image of this workbench part. If this value changes the part must fire a property listener event with PROP_TITLE.

The title image is usually used to populate the title bar of this part's visual container. Since this image is managed by the part itself, callers must not dispose the returned image.

Returns:: the title image

getTitleToolTip


String getTitleToolTip()

Returns the title tool tip text of this workbench part. An empty string result indicates no tool tip. If this value changes the part must fire a property listener event with PROP_TITLE.

The tool tip text is used to populate the title bar of this part's visual container.

Returns:: the workbench part title tool tip (not null)

removePropertyListener

void removePropertyListener(
IPropertyListener listener)

Removes the given property listener from this workbench part. Has no affect if an identical listener is not registered.

Parameters:: listener - a property listener

setFocus

void setFocus()

Asks this part to take focus within the workbench. Parts must assign focus to one of the controls contained in the part's parent composite.

Clients should not call this method (the workbench calls this method at appropriate times). To have the workbench activate a part, use IWorkbenchPage.activate(IWorkbenchPart) instead.