Eclipse GEF and Draw2d Plug-in Developer Guide (Galileo) - OrderedLayoutEditPolicy (Eclipse GEF API Specification)

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org.eclipse.gef.editpolicies
Class OrderedLayoutEditPolicy

java.lang.Object
  

org.eclipse.gef.editpolicies.AbstractEditPolicy
      

org.eclipse.gef.editpolicies.GraphicalEditPolicy
          

org.eclipse.gef.editpolicies.LayoutEditPolicy
              
org.eclipse.gef.editpolicies.OrderedLayoutEditPolicy

All Implemented Interfaces:: EditPolicy, RequestConstants

Direct Known Subclasses:: FlowLayoutEditPolicy

public abstract class OrderedLayoutEditPolicy
extends LayoutEditPolicy

A LayoutEditPolicy for use with LayoutManagers that take no constraints. Such layout managers typically position children in coordinates based on their order in getChildren(). Therefore, this EditPolicy must perform the inverse mapping. Given a mouse location from the User, the policy must determine the index at which the child[ren] should be added/created.

Since:: 2.0

Field Summary

Fields inherited from interface org.eclipse.gef. EditPolicy

COMPONENT_ROLE, CONNECTION_BENDPOINTS_ROLE, CONNECTION_ENDPOINTS_ROLE, CONNECTION_ROLE, CONTAINER_ROLE, DIRECT_EDIT_ROLE, GRAPHICAL_NODE_ROLE, LAYOUT_ROLE, NODE_ROLE, PRIMARY_DRAG_ROLE, SELECTION_FEEDBACK_ROLE, TREE_CONTAINER_ROLE

Fields inherited from interface org.eclipse.gef. RequestConstants

REQ_ADD, REQ_ALIGN, REQ_ALIGN_CHILDREN, REQ_CLONE, REQ_CONNECTION_END, REQ_CONNECTION_START, REQ_CREATE, REQ_CREATE_BENDPOINT, REQ_DELETE, REQ_DELETE_DEPENDANT, REQ_DIRECT_EDIT, REQ_MOVE, REQ_MOVE_BENDPOINT, REQ_MOVE_CHILDREN, REQ_OPEN, REQ_ORPHAN, REQ_ORPHAN_CHILDREN, REQ_RECONNECT_SOURCE, REQ_RECONNECT_TARGET, REQ_RESIZE, REQ_RESIZE_CHILDREN, REQ_SELECTION, REQ_SELECTION_HOVER

Constructor Summary

OrderedLayoutEditPolicy ()


Method Summary

protected abstract Command createAddCommand ( EditPart child, EditPart after)
          Returns the Command to add the specified child after a reference EditPart.

protected EditPolicy createChildEditPolicy ( EditPart child)
          Since Ordered layouts generally don't use constraints, a NonResizableEditPolicy is used by default for children.

protected abstract Command createMoveChildCommand ( EditPart child, EditPart after)
          Returns the Command to move the specified child before the given reference EditPart.

protected Command getAddCommand ( Request req)
          This method is overridden from the superclass to calculate the index at which the children should be added.

protected abstract EditPart getInsertionReference ( Request request)
          Calculates a reference EditPart using the specified Request.

protected Command getMoveChildrenCommand ( Request request)
          A move is interpreted here as a change in order of the children.

Methods inherited from class org.eclipse.gef.editpolicies. LayoutEditPolicy

activate, createListener, createSizeOnDropFeedback, deactivate, decorateChild, decorateChildren, eraseLayoutTargetFeedback, eraseSizeOnDropFeedback, eraseTargetFeedback, getCloneCommand, getCommand, getCreateCommand, getCreationFeedbackOffset, getDeleteDependantCommand, getLayoutContainer, getOrphanChildrenCommand, getSizeOnDropFeedback, getSizeOnDropFeedback, getTargetEditPart, setListener, showLayoutTargetFeedback, showSizeOnDropFeedback, showTargetFeedback, undecorateChild, undecorateChildren

Methods inherited from class org.eclipse.gef.editpolicies. GraphicalEditPolicy

addFeedback, getFeedbackLayer, getHostFigure, getLayer, removeFeedback

Methods inherited from class org.eclipse.gef.editpolicies. AbstractEditPolicy

debugFeedback, eraseSourceFeedback, getHost, setHost, showSourceFeedback, toString, understandsRequest

Methods inherited from class java.lang.Object

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

Constructor Detail

OrderedLayoutEditPolicy

public OrderedLayoutEditPolicy()

Method Detail

createAddCommand

protected abstract 
Command createAddCommand(
EditPart child,
                                            
EditPart after)

Returns the Command to add the specified child after a reference EditPart. If the reference is null, the child should be added as the first child.

Parameters:: child - the child being added; after - null or a reference EditPart
Returns:: a Command to add the child

createChildEditPolicy

protected 
EditPolicy createChildEditPolicy(
EditPart child)

Since Ordered layouts generally don't use constraints, a NonResizableEditPolicy is used by default for children. Subclasses may override this method to supply a different EditPolicy.

Specified by:: createChildEditPolicy in class LayoutEditPolicy

Parameters:: child - the child EditPart
Returns:: an EditPolicy to be installed as the EditPolicy.PRIMARY_DRAG_ROLE
See Also:: LayoutEditPolicy.createChildEditPolicy(EditPart)

createMoveChildCommand

protected abstract 
Command createMoveChildCommand(
EditPart child,
                                                  
EditPart after)

Returns the Command to move the specified child before the given reference EditPart. If the reference is null, the child should be moved in front of all children.

A move is a change in the order of the children, which indirectly causes a change in location on the screen.

Parameters:: child - the child being moved; after - null or the EditPart that should be after (or to the right of) the child being moved
Returns:: a Command to move the child

getAddCommand

protected 
Command getAddCommand(
Request req)

This method is overridden from the superclass to calculate the index at which the children should be added. The index is determined by finding a reference EditPart, and adding the new child[ren] after that reference part. null is used to indicate that the child[ren] should be added at the beginning.

Subclasses must override createAddCommand(EditPart, EditPart), and should not override this method.

Overrides:: getAddCommand in class LayoutEditPolicy

Parameters:: req - the ADD Request
Returns:: A command to perform the ADD.
See Also:: LayoutEditPolicy.getAddCommand(Request)

getInsertionReference

protected abstract 
EditPart getInsertionReference(
Request request)

Calculates a reference EditPart using the specified Request. The EditPart returned is used to mark the index coming after that EditPart. null is used to indicate the index that comes after no EditPart, that is, it indicates the very last index.

Parameters:: request - the Request
Returns:: null or a reference EditPart

getMoveChildrenCommand

protected 
Command getMoveChildrenCommand(
Request request)

A move is interpreted here as a change in order of the children. This method obtains the proper index, and then calls createMoveChildCommand(EditPart, EditPart), which subclasses must implement. Subclasses should not override this method.