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org.eclipse.core.commands.operations
Interface IUndoableOperation
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All Known Subinterfaces:
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ICompositeOperation
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All Known Implementing Classes:
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AbstractOperation,
AbstractWorkspaceOperation,
CopyProjectOperation,
CopyResourcesOperation,
CreateFileOperation,
CreateFolderOperation,
CreateMarkersOperation,
CreateProjectOperation,
DeleteMarkersOperation,
DeleteResourcesOperation,
MoveProjectOperation,
MoveResourcesOperation,
TriggeredOperations,
UpdateMarkersOperation
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public interface IUndoableOperation
IUndoableOperation defines an operation that can be executed, undone, and
redone. Operations typically have fully defined parameters. That is, they are
usually created after the user has been queried for any input needed to
define the operation.
Operations determine their ability to execute, undo, or redo according to the
current state of the application. They do not make decisions about their
validity based on where they occur in the operation history. That is left to
the particular operation history.
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Since:
- 3.1
addContext
void addContext(
IUndoContext context)
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Add the specified context to the operation. If a context equal to the
specified context is already present, do not add it again. Note that
determining whether a context is already present is based on equality,
not whether the context matches (
IUndoContext.matches(IUndoContext))
another context.
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Parameters:
-
context - the context to be added
canExecute
boolean canExecute()
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Returns whether the operation can be executed in its current state.
Note: The computation for this method must be fast, as it is called
frequently. If necessary, this method can be optimistic in its
computation (returning true) and later perform more time-consuming
computations during the actual execution of the operation, returning the
appropriate status if the operation cannot actually execute at that time.
-
-
Returns:
-
true if the operation can be executed;
false otherwise.
canRedo
boolean canRedo()
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Returns whether the operation can be redone in its current state.
Note: The computation for this method must be fast, as it is called
frequently. If necessary, this method can be optimistic in its
computation (returning true) and later perform more time-consuming
computations during the actual redo of the operation, returning the
appropriate status if the operation cannot actually be redone at that
time.
-
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Returns:
-
true if the operation can be redone;
false otherwise.
canUndo
boolean canUndo()
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Returns whether the operation can be undone in its current state.
Note: The computation for this method must be fast, as it is called
frequently. If necessary, this method can be optimistic in its
computation (returning true) and later perform more time-consuming
computations during the actual undo of the operation, returning the
appropriate status if the operation cannot actually be undone at that
time.
-
-
Returns:
-
true if the operation can be undone;
false otherwise.
dispose
void dispose()
- Dispose of the operation. This method is used when the operation is no
longer kept in the history. Implementers of this method typically
unregister any listeners.
-
execute
IStatus execute(
IProgressMonitor monitor,
IAdaptable info)
throws
ExecutionException
- Execute the operation. This method should only be called the first time
that an operation is executed.
-
-
Parameters:
-
monitor - the progress monitor (or null) to use for
reporting progress to the user. -
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.
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Returns:
- the IStatus of the execution. The status severity should be set
to
OK if the operation was successful, and
ERROR if it was not. Any other status is assumed
to represent an incompletion of the execution.
-
Throws:
-
ExecutionException
- if an exception occurred during execution.
getContexts
IUndoContext[] getContexts()
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Returns the array of contexts that have been assigned to the operation.
This method may be called by the operation history from inside a
synchronized block. To avoid deadlock conditions, implementers of this
method must avoid dispatching and waiting on threads that modify the
operation history during this method.
-
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Returns:
- the array of contexts
getLabel
String getLabel()
- Return the label that should be used to show the name of the operation to
the user. This label is typically combined with the command strings shown
to the user in "Undo" and "Redo" user interfaces.
-
-
Returns:
- the String label. Should never be
null.
hasContext
boolean hasContext(
IUndoContext context)
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Returns whether the operation has a matching context for the specified
context.
This method may be called by the operation history from inside a
synchronized block. To avoid deadlock conditions, implementers of this
method must avoid dispatching and waiting on threads that modify the
operation history during this method.
-
-
Parameters:
-
context - the context in question
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Returns:
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true if the context is present, false
if it is not. -
See Also:
-
IUndoContext.matches(IUndoContext)
redo
IStatus redo(
IProgressMonitor monitor,
IAdaptable info)
throws
ExecutionException
- Redo the operation. This method should only be called after an operation
has been undone.
-
-
Parameters:
-
monitor - the progress monitor (or null) to use for
reporting progress to the user. -
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.
-
Returns:
- the IStatus of the redo. The status severity should be set to
OK if the redo was successful, and
ERROR if it was not. Any other status is assumed
to represent an incompletion of the redo.
-
Throws:
-
ExecutionException
- if an exception occurred during redo.
removeContext
void removeContext(
IUndoContext context)
- Remove the specified context from the operation. This method has no
effect if the context is not equal to another context in the context
list. Note that determining whether a context is present when removing it
is based on equality, not whether the context matches (
IUndoContext.matches(IUndoContext)) another context.
-
-
Parameters:
-
context - the context to be removed
undo
IStatus undo(
IProgressMonitor monitor,
IAdaptable info)
throws
ExecutionException
- Undo the operation. This method should only be called after an operation
has been executed.
-
-
Parameters:
-
monitor - the progress monitor (or null) to use for
reporting progress to the user. -
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.
-
Returns:
- the IStatus of the undo. The status severity should be set to
OK if the redo was successful, and
ERROR if it was not. Any other status is assumed
to represent an incompletion of the undo.
-
Throws:
-
ExecutionException
- if an exception occurred during undo.
Guidelines for using Eclipse APIs.
Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.
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