org.eclipse.core.commands.operations
Interface IOperationApprover
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All Known Subinterfaces:
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IOperationApprover2
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All Known Implementing Classes:
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LinearUndoEnforcer,
LinearUndoViolationDetector,
LinearUndoViolationUserApprover,
NonLocalUndoUserApprover
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public interface IOperationApprover
IOperationApprover defines an interface for approving the undo or redo of a
particular operation within an operation history. Operations that are
candidates for undo or redo have already been validated against their current
state and according to the rules of the history.
By the time an IOperationApprover is consulted, the undo has already been
requested. Approvers should return an IStatus object with
severity OK if the operation should proceed, and any other
severity if it should not. When an operation is not approved, it is expected
that the object not allowing the operation has already consulted the user if
necessary or otherwise provided any necessary information to the user about
the fact that the operation is not approved.
Operation approvers must be prepared to receive the approval messages from a
background thread. Any UI access occurring inside the implementation must be
properly synchronized using the techniques specified by the client's widget
library.
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Since:
- 3.1
proceedRedoing
IStatus proceedRedoing(
IUndoableOperation operation,
IOperationHistory history,
IAdaptable info)
- Return a status indicating whether the specified operation should be
redone. Any status that does not have severity
IStatus.OK
will not be approved. Implementers should not assume that the redo will
be performed when the status is OK, since other operation
approvers may veto the redo.
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Parameters:
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operation - the operation to be redone -
history - the history redoing the operation -
info - the IAdaptable (or null) provided by the
caller in order to supply UI information for prompting the
user if necessary. When this parameter is not
null, it should minimally contain an adapter
for the org.eclipse.swt.widgets.Shell.class. Even if UI
information is provided, the implementation of this method
must be prepared for being called from a background thread.
Any UI access must be properly synchronized using the
techniques specified by the client's widget library.
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Returns:
- the IStatus describing whether the operation is approved. The
redo will not proceed if the status severity is not
OK, and the caller requesting the redo will be
returned the status that caused the rejection. Any other status
severities will not be interpreted by the history.
proceedUndoing
IStatus proceedUndoing(
IUndoableOperation operation,
IOperationHistory history,
IAdaptable info)
- Return a status indicating whether the specified operation should be
undone. Any status that does not have severity
IStatus.OK
will not be approved. Implementers should not assume that the undo will
be performed when the status is OK, since other operation
approvers can veto the undo.
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Parameters:
-
operation - the operation to be undone -
history - the history undoing the operation -
info - the IAdaptable (or null) provided by the
caller in order to supply UI information for prompting the
user if necessary. When this parameter is not
null, it should minimally contain an adapter
for the org.eclipse.swt.widgets.Shell.class. Even if UI
information is provided, the implementation of this method
must be prepared for being called from a background thread.
Any UI access must be properly synchronized using the
techniques specified by the client's widget library.
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Returns:
- the IStatus describing whether the operation is approved. The
undo will not proceed if the status severity is not
OK, and the caller requesting the undo will be
returned the status that caused the rejection. Any other status
severities will not be interpreted by the history.
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