Class CompositeChange

  • All Implemented Interfaces:
    IAdaptable

    public class CompositeChange
    extends Change
    Represents a composite change. Composite changes can be marked as synthetic. A synthetic composite changes might not be rendered in the refactoring preview tree to save display real-estate.

    Clients may subclass this class.

    Since:
    3.0
    See Also:
    Change
    • Constructor Detail

      • CompositeChange

        public CompositeChange​(String name)
        Creates a new composite change with the given name.
        Parameters:
        name - the human readable name of the change. Will be used to display the change in the user interface
      • CompositeChange

        public CompositeChange​(String name,
                               Change[] children)
        Creates a new composite change with the given name and array of children.
        Parameters:
        name - the human readable name of the change. Will be used to display the change in the user interface
        children - the initial array of children
    • Method Detail

      • isSynthetic

        public boolean isSynthetic()
        Returns whether this change is synthetic or not.
        Returns:
        trueif this change is synthetic; otherwise false
      • markAsSynthetic

        public void markAsSynthetic()
        Marks this change as synthetic.
      • getName

        public String getName()
        Description copied from class: Change
        Returns the human readable name of this change. The name MUST not be null.
        Specified by:
        getName in class Change
        Returns:
        the human readable name of this change
      • add

        public void add​(Change change)
        Adds the given change to the list of children. The change to be added can be null. Adding a "null" change does nothing.
        Parameters:
        change - the change to add
      • addAll

        public void addAll​(Change[] changes)
        Adds all changes in the given array to the list of children.
        Parameters:
        changes - the changes to add
      • merge

        public void merge​(CompositeChange change)
        Merges the children of the given composite change into this change. This means the changes are removed from the given composite change and added to this change.
        Parameters:
        change - the change to merge
      • remove

        public boolean remove​(Change change)
        Removes the given change from the list of children.
        Parameters:
        change - the change to remove
        Returns:
        true if the change contained the given child; otherwise false is returned
      • clear

        public Change[] clear()
        Removes all changes from this composite change.
        Returns:
        the list of changes removed from this composite change
        Since:
        3.1
      • getChildren

        public Change[] getChildren()
        Returns the children managed by this composite change.
        Returns:
        the children of this change or an empty array if no children exist
      • setEnabled

        public void setEnabled​(boolean enabled)
        Sets whether this change is enabled or not.

        The composite change sends setEnabled to all its children.

        Client are allowed to extend this method.

        Overrides:
        setEnabled in class Change
        Parameters:
        enabled - true to enable this change; false otherwise
      • initializeValidationData

        public void initializeValidationData​(IProgressMonitor pm)
        Hook method to initialize some internal state to provide an adequate answer for the isValid method. This method gets called after a change or a whole change tree has been created.

        Typically this method is implemented in one of the following ways:

        • the change hooks up a listener on some delta notification mechanism and marks itself as invalid if it receives a certain delta. Is this the case the implementor must take care of unhooking the listener in dispose.
        • the change remembers some information allowing to decide if a change object is still valid when isValid is called.

        For example, a change object that manipulates the content of an IFile could either listen to resource changes and detect that the file got changed or it could remember some content stamp and compare it with the actual content stamp when isValid is called.

        The composite change sends initializeValidationData to all its children.

        Client are allowed to extend this method.

        Specified by:
        initializeValidationData in class Change
        Parameters:
        pm - a progress monitor
      • isValid

        public RefactoringStatus isValid​(IProgressMonitor pm)
                                  throws CoreException
        Verifies that this change object is still valid and can be executed by calling perform. If a refactoring status with a severity of RefactoringStatus.FATAL is returned then the change has to be treated as invalid and can no longer be executed. Performing such a change produces an unspecified result and will very likely throw an exception.

        This method is also called by the UndoManager to decide if an undo or redo change is still valid and therefore can be executed.

        The composite change sends isValid to all its children until the first one returns a status with a severity of FATAL . If one of the children throws an exception the remaining children will not receive the isValid call.

        Client are allowed to extend this method.

        Specified by:
        isValid in class Change
        Parameters:
        pm - a progress monitor.
        Returns:
        a refactoring status describing the outcome of the validation check
        Throws:
        CoreException - if an error occurred during validation check. The change is to be treated as invalid if an exception occurs
      • perform

        public Change perform​(IProgressMonitor pm)
                       throws CoreException
        Performs this change. If this method is called on an invalid or disabled change object the result is unspecified. Changes should in general not respond to IProgressMonitor.isCanceled() since canceling a change tree in the middle of its execution leaves the workspace in a half changed state.

        The composite change sends perform to all its enabled children. If one of the children throws an exception the remaining children will not receive the perform call. In this case the method getUndoUntilException can be used to get an undo object containing the undo objects of all executed children.

        Client are allowed to extend this method.

        Specified by:
        perform in class Change
        Parameters:
        pm - a progress monitor
        Returns:
        the undo change for this change object or null if no undo is provided
        Throws:
        CoreException - if an error occurred during change execution
      • internalHandleException

        protected void internalHandleException​(Change change,
                                               Throwable t)
        Note: this is an internal method and should not be overridden outside of the refactoring framework.

        The method gets called if one of the changes managed by this composite change generates an exception when performed.

        Parameters:
        change - the change that caused the exception
        t - the exception itself
        Restriction:
        This method is not intended to be referenced by clients.
      • internalContinueOnCancel

        protected boolean internalContinueOnCancel()
        Note: this is an internal method and should not be overridden outside of the refactoring framework.

        The method gets called if one of the changes managed by this composite change generates an operation canceled exception when performed.

        Returns:
        true if performing the change should continue on cancel; otherwise false
        Since:
        3.1
        Restriction:
        This method is not intended to be referenced by clients.
      • internalProcessOnCancel

        protected boolean internalProcessOnCancel​(Change change)
        Note: this is an internal method and should not be overridden outside of the refactoring framework.

        The method gets called if the execution of this change got canceled, but internalContinueOnCancel returned true.

        Parameters:
        change - the change to perform
        Returns:
        true if the given change should be performed although the execution got canceled; otherwise false
        Since:
        3.1
        Restriction:
        This method is not intended to be referenced by clients.
      • dispose

        public void dispose()
        Disposes this change. Subclasses that override this method typically unregister listeners which got registered during the call to initializeValidationData.

        Subclasses may override this method.

        The composite change sends dispose to all its children. It is guaranteed that all children receive the dispose call.

        Overrides:
        dispose in class Change
      • getUndoUntilException

        public Change getUndoUntilException()
        Returns the undo object containing all undo changes of those children that got successfully executed while performing this change. Returns null if all changes were executed successfully or if there's nothing to undo.

        This method is not intended to be overridden or extended.

        Returns:
        the undo object containing all undo changes of those children that got successfully executed while performing this change, or null if all changes were executed successfully or if there's nothing to undo.
      • createUndoChange

        protected Change createUndoChange​(Change[] childUndos)
        Hook to create an undo change. The method should be overridden by clients which provide their own composite change to create a corresponding undo change.
        Parameters:
        childUndos - the child undo. The undo edits appear in the list in the reverse order of their execution. So the first change in the array is the undo change of the last change that got executed.
        Returns:
        the undo change
      • getAffectedObjects

        public Object[] getAffectedObjects()
        Description copied from class: Change
        Returns the elements affected by this change or null if the affected elements cannot be determined. Returns an empty array if the change doesn't modify any elements.

        This default implementation returns null to indicate that the affected elements are unknown. Subclasses should reimplement this method if they can compute the set of affected elements.

        Overrides:
        getAffectedObjects in class Change
        Returns:
        the elements affected by this change or null if the affected elements cannot be determined
      • getModifiedElement

        public Object getModifiedElement()
        Description copied from class: Change
        Returns the element modified by this Change. The method may return null if the change isn't related to an element.
        Specified by:
        getModifiedElement in class Change
        Returns:
        the element modified by this change