IChangePreviewViewer (Eclipse Platform API Specification)

```
public interface IChangePreviewViewer
```
Viewer to present the preview for a Change.
Viewers are associated with a change object via the extension point org.eclipse.ltk.ui.refactoring.changePreviewViewers. Implementors of this extension point must therefore implement this interface.

To ensure visual consistency across all provided preview viewers the widget hierarchy provided through the method createControl(Composite) has to use a ViewForm as its root widget.

Clients of this interface should call createControl before calling setInput.

Since:

3.0

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`createControl(Composite parent)`	Creates the preview viewer's widget hierarchy.
`Control`	`getControl()`	Returns the preview viewer's SWT control.
`void`	`setInput(ChangePreviewViewerInput input)`	Sets the preview viewer's input element.

- Method Detail
  - createControl
```
void createControl(Composite parent)
```
    Creates the preview viewer's widget hierarchy. This method is only called once. Method getControl() should be used to retrieve the widget hierarchy.
    
    Parameters:
    
    parent - the parent for the widget hierarchy
    
    See Also:
    
    getControl()
  - getControl
```
Control getControl()
```
    Returns the preview viewer's SWT control.
    
    Returns:
    
    the preview viewer's SWT control or null is the widget hierarchy hasn't been created yet
  - setInput
```
void setInput(ChangePreviewViewerInput input)
```
    Sets the preview viewer's input element.
    
    Parameters:
    
    input - the input element