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| Provides a framework for viewers, which are model-based |
| content adapters for SWT widgets. |
| <h2> |
| Package Specification</h2> |
| A viewer is a model-based adapter on an SWT widget. Each viewer has |
| four parts: |
| <blockquote> |
| <li> |
| an <b>input</b> - the object that serves as the viewer's model</li> |
| |
| <li> |
| a <b>widget</b> - the SWT control through which the viewer's model is displayed</li> |
| |
| <li> |
| a <b>content provider</b> - mediates between the model and viewer</li> |
| |
| <li> |
| a <b>label provider</b> - maps model objects to displayable labels containing |
| text and/or an image</li> |
| </blockquote> |
| This package contains the viewer framework. The viewer framework is an |
| independent JFace module. Using it requires a knowledge of SWT, but does |
| not require familiarity with any of the other JFace modules. The framework |
| consists of abstract base classes for viewers (<tt>Viewer</tt>, <tt>StructuredViewer</tt>, |
| <tt>AbstractTreeViewer</tt>) together with concrete viewer classes (<tt>ListViewer</tt>, |
| <tt>TreeViewer</tt>, |
| <tt>TableViewer</tt>, |
| <tt>TableTreeViewer</tt>, <tt>CheckboxTreeViewer</tt>, |
| and <tt>CheckboxTableViewer</tt>), |
| and various lesser support classes. The concrete structured viewer classes |
| are ready-to-use and have built-in support for drag-and-drop, filtering |
| (<tt>IViewerFilter</tt> and <tt>ViewerFilter</tt>), and sorting (<tt>IViewerSorter</tt> |
| and <tt>ViewerSorter</tt>); these classes may also be subclassed further |
| if required. |
| <p>In general terms, creating a viewer involves the following steps: |
| <ul> |
| <li> |
| instantiating a viewer on some pre-existing SWT widget,</li> |
| |
| <li> |
| setting the viewer's content provider (an object implementing <tt>IContentProvider</tt>),</li> |
| |
| <li> |
| setting the viewer's label provider (an object implementing |
| <tt>ILabelProvider</tt>),</li> |
| |
| <li> |
| and, finally, setting the viewer's input.</li> |
| </ul> |
| Once a viewer's input is set, the viewer becomes active. As the model changes, |
| it is the content provider's responsibility to respond to changes to the |
| model by telling the viewer what to change (done by calling add and remove |
| methods on the viewer). An existing viewer may be retargeted by giving |
| it a different object as input; the viewer is responsible for informing |
| the content provider of these kinds of wholesale changes (<tt>IContentProvider.inputChanged</tt>). |
| Also, each viewer registers with its label provider for notification of |
| changes that would affect what the viewer displays (see <tt>ILabelProviderListener.stateChanged</tt>). |
| <p>Note: None of the classes in this package maintain global state. |
| <br> |
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