org.eclipse.gef
Interface EditPart
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All Known Subinterfaces:
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ConnectionEditPart,
GraphicalEditPart,
NodeEditPart,
RootEditPart,
TreeEditPart
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All Known Implementing Classes:
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AbstractConnectionEditPart,
AbstractEditPart,
AbstractGraphicalEditPart,
AbstractTreeEditPart,
GraphicalRootEditPart,
RootTreeEditPart,
SimpleRootEditPart
- public interface EditPart
EditParts are the building blocks of GEF Viewers. As the Controller, an
EditPart ties the application's model to a visual representation. EditParts are
responsible for making changes to the model. EditParts typically control a single
model object or a coupled set of object. Visual representations include
Figures and
TreeItems. Model objects are often composed of other objects that the User will
interact with. Similarly, EditParts can be composed of or have references to other
EditParts.
The creator of an EditPart should call only setModel(Object). The remaining API is
used mostly by Tools, EditPolicies, and other EditParts. CHANGES are made to the
model, not the EditPart.
Most interaction with EditParts is achieved using
Requests. A Request
specifies the type of interaction. Requests are used in
targeting, filtering the selection (using
understandsRequest(Request)), graphical
showSourceFeedback(Request)
feedback, and most importantly,
obtaining commands. Only
Commands should change the model.
IMPORTANT: This interface is not intended to be implemented by clients.
Clients should inherit from
AbstractEditPart. New
methods may be added in the future.
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Field Summary
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static int
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SELECTED
Used to indicate non-primary selection |
static int
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SELECTED_NONE
Used to indicate no selection |
static int
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SELECTED_PRIMARY
Used to indicate primary selection, or "Anchor" selection.
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SELECTED_NONE
public static final int SELECTED_NONE
- Used to indicate no selection
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See Also:
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Constant Field Values
SELECTED
public static final int SELECTED
- Used to indicate non-primary selection
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See Also:
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Constant Field Values
SELECTED_PRIMARY
public static final int SELECTED_PRIMARY
- Used to indicate primary selection, or "Anchor" selection.
Primary selection is defined as the last object selected.
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See Also:
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Constant Field Values
activate
public void activate()
- Activates the EditPart. EditParts that observe a dynamic model or support editing must
be active.
Called by the managing EditPart, or the Viewer in the case of the
RootEditPart.
This method may be called again once
deactivate() has been called.
During activation the receiver should:
- begin to observe its model if appropriate, and should continue the observation
until
deactivate() is called.
- activate all of its EditPolicies. EditPolicies may also observe the model,
although this is rare. But it is common for EditPolicies to contribute additional
visuals, such as selection handles or feedback during interactions. Therefore it is
necessary to tell the EditPolicies when to start doing this, and when to stop.
- call activate() on the EditParts it manages. This includes its children, and for
GraphicalEditParts, its source connections.
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addEditPartListener
public void addEditPartListener(
EditPartListener listener)
- Adds a listener to the EditPart.
Duplicate calls result in duplicate notification.
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Parameters:
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listener - the Listener
addNotify
public void addNotify()
- Called after the EditPart has been added to its parent. This is used to
indicate to the EditPart that it should refresh itself for the first time.
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deactivate
public void deactivate()
- Deactivates the EditPart. EditParts that observe a dynamic model or support editing
must be active.
deactivate() is guaranteed to be called when an
EditPart will no longer be used. Called by the managing EditPart, or the Viewer in the
case of the
RootEditPart. This method may be called multiple times.
During deactivation the receiver should:
- remove all listeners that were added in
activate()
- deactivate all of its EditPolicies. EditPolicies may be contributing
additional visuals, such as selection handles or feedback during interactions.
Therefore it is necessary to tell the EditPolicies when to start doing this, and
when to stop.
- call deactivate() on the EditParts it manages. This includes its children,
and for
GraphicalEditParts, its source connections.
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eraseSourceFeedback
public void eraseSourceFeedback(
Request request)
- Erases source feedback for the specified
Request. A Request is used to
describe the type of source feedback that should be erased. This method should only be
called once to erase feedback. It should only be called in conjunction with a prior
call to
showSourceFeedback(Request).
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Parameters:
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request - the type of feedback that is being erased
eraseTargetFeedback
public void eraseTargetFeedback(
Request request)
- Erases target feedback for the specified
Request. A Request is used to
describe the type of target feedback that should be erased. This method should only be
called once to erase feedback. It should only be called in conjunction with a prior
call to
showTargetFeedback(Request).
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Parameters:
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request - the type of feedback that is being erased
getChildren
public java.util.List getChildren()
- Returns the List of children
EditParts. This method should rarely be
called, and is only made public so that helper objects of this EditPart, such as
EditPolicies, can obtain the children. The returned List may be by reference, and
should never be modified.
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Returns:
- a
List of children
getCommand
public
Command getCommand(
Request request)
- Returns the
Command to perform the specified Request or null.
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Parameters:
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request - describes the Command being requested
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Returns:
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null or a Command
getDragTracker
public
DragTracker getDragTracker(
Request request)
- Returns a
DragTracker for dragging this EditPart. The
SelectionTool is the only Tool by default that
calls this method. The SelectionTool will use a
SelectionRequest to provide information such as which mouse
button is down, and what modifier keys are pressed.
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Parameters:
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request - a Request indicating the context of the drag
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Returns:
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null or a DragTracker
getEditPolicy
public
EditPolicy getEditPolicy(java.lang.Object key)
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Parameters:
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key - the key identifying the EditPolicy
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Returns:
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null or the EditPolicy installed with the given key
getModel
public java.lang.Object getModel()
- Returns the primary model object that this EditPart represents. EditParts may
correspond to more than one model object, or even no model object. In practice, the
Object returned is used by other EditParts to identify this EditPart. In addition,
EditPolicies probably rely on this method to build Commands that operate on the model.
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Returns:
- the primary model object
getParent
public
EditPart getParent()
- Returns the parent
EditPart. This method should only be called internally
or by helpers such as EditPolicies.
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Returns:
- the parent
getRoot
public
RootEditPart getRoot()
- Returns the
RootEditPart. This method should only be called internally or by
helpers such as edit policies. The Root can be used to get the Viewer.
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Returns:
- the
RootEditPart
getSelected
public int getSelected()
- Returns the selected state of this EditPart. This method should only be called
internally or by helpers such as EditPolicies.
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Returns:
- one of:
getTargetEditPart
public
EditPart getTargetEditPart(
Request request)
- Return the
EditPart that should be used as the target for the
specified Request. Tools will generally call this method with the mouse
location so that the receiver can implement drop targeting. Typically, if this EditPart
is not the requested target (for example, this EditPart is not a composite), it will
forward the call to its parent.
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Parameters:
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request - the type of target being requested
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Returns:
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null or the target
getViewer
public
EditPartViewer getViewer()
- Convenience method for returning the
EditPartViewer for this part.
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Returns:
- the EditPartViewer
hasFocus
public boolean hasFocus()
- Returns true if this EditPart has focus. The focus EditPart is a property of the
EditPartViewer. The Viewer keeps this property in sync with its focus.
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Returns:
- true if the EditPart has focus
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See Also:
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EditPartViewer.getFocusEditPart()
installEditPolicy
public void installEditPolicy(java.lang.Object role,
EditPolicy editPolicy)
- Installs an EditPolicy for a specified role. A role is is simply an
Object used to identify the EditPolicy. An example of a role is layout.
EditPolicy.LAYOUT_ROLE is generally used as the key for this EditPolicy.
null is a valid value for reserving a location.
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Parameters:
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role - an identifier used to key the EditPolicy -
editPolicy - the EditPolicy
isActive
public boolean isActive()
- returns
true if the EditPart is active. Editparts are active after
activate() is called, and until
deactivate() is called.
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Returns:
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true when active
isSelectable
public boolean isSelectable()
- Returns
true if the EditPart is selectable. A selectable EditPart may be
selected as a result of the
SelectionTool receiving a
mouse down, or as a result of the User pressing a key to change selection.
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Returns:
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true if the receiver can be selected
performRequest
public void performRequest(
Request request)
- Performs the specified Request. This method can be used to send a generic message
to an EditPart. If the EditPart interprets this request to mean make a change
in the model, it should still use
Commands and the
CommandStack so that the change is undoable. The CommandStack is available
from the EditDomain.
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Parameters:
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request - the request to be performed
refresh
public void refresh()
- Called to force a refresh of this EditPart. All visuals properties will be updated, as
well as structural features like children.
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removeEditPartListener
public void removeEditPartListener(
EditPartListener listener)
- Removes the first occurance of the specified listener from the list of listeners. Does
nothing if the listener was not present.
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Parameters:
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listener - the listener being removed
removeEditPolicy
public void removeEditPolicy(java.lang.Object role)
- Removes the EditPolicy for the given role. The EditPolicy is deactivated if it
is active. The position for that role is maintained with
null in the place
of the old EditPolicy.
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Parameters:
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role - the key identifying the EditPolicy to be removed -
See Also:
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installEditPolicy(Object, EditPolicy)
removeNotify
public void removeNotify()
- Called when the EditPart is being permanently removed from its
EditPartViewer.
This indicates that the EditPart will no longer be in the Viewer, and therefore should
remove itself from the Viewer. This method is not called when a Viewer is
disposed. It is only called when the EditPart is removed from its parent. This method
is the inverse of
addNotify()
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setFocus
public void setFocus(boolean hasFocus)
- Set the focus property to reflect the value in the EditPartViewer. Focus is
determined by the EditPartViewer.
Focus is considered to be part of the selected state, changing this value
will fire
EditPartListener.selectedStateChanged(EditPart).
IMPORTANT: This method should only be called by the EditPartViewer.
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Parameters:
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hasFocus - boolean indicating if this part has focus
setModel
public void setModel(java.lang.Object model)
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Sets the model. This method is made public to
facilitate the use of
EditPartFactories.
IMPORTANT: This method should only be called once.
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Parameters:
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model - the Model
setParent
public void setParent(
EditPart parent)
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Sets the parent. This should only be called by the
parent EditPart.
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Parameters:
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parent - the parent EditPart
setSelected
public void setSelected(int value)
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Sets the selected state property to reflect the
selection in the EditPartViewer. Fires selectedStateChanged(EditPart) to any
EditPartListeners. Selection is maintained by the EditPartViewer.
IMPORTANT: This method should only be called by the EditPartViewer.
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Parameters:
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value - an enum indicating the selected state -
See Also:
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getSelected()
showSourceFeedback
public void showSourceFeedback(
Request request)
- Shows or updates source feedback for the given request. This method may be called
multiple times so that the feedback can be updated for changes in the request, such as
the mouse location changing.
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Parameters:
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request - request describing the type of feedback
showTargetFeedback
public void showTargetFeedback(
Request request)
- Shows or updates target feedback for the given request. This method can be called
multiple times so that the feedback can be updated for changes in the request, such as
the mouse location changing.
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Parameters:
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request - request describing the type of feedback
understandsRequest
public boolean understandsRequest(
Request request)
- Used to filter EditParts out of the current selection. If an operation is going
to be performed on the current selection, the selection can first be culled to remove
EditParts that do not participate in the operation. For example, when aligning the
left edges of GraphicalEditParts, it makes sense to ignore any selected
ConnectionEditParts, as they cannot be aligned.
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Parameters:
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request - a Request describing an operation of some type
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Returns:
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true if Request is understood
Copyright (c) IBM Corp. and others 2000, 2007. All Rights Reserved.
