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org.eclipse.jface.viewers
Class Viewer  

java.lang.Object
  org.eclipse.jface.viewers.Viewer

All Implemented Interfaces:

IInputProvider, IInputSelectionProvider, ISelectionProvider

Direct Known Subclasses:

ContentViewer

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public abstract class Viewer

extends java.lang.Object

implements IInputSelectionProvider

A viewer is a model-based adapter on a widget.

A viewer can be created as an adapter on a pre-existing control (e.g., creating a ListViewer on an existing List control). All viewers also provide a convenience constructor for creating the control.

Implementing a concrete viewer typically involves the following steps:

• create SWT controls for viewer (in constructor) (optional)
• initialize SWT controls from input (inputChanged)
• define viewer-specific update methods
• support selections (setSelection, getSelection)

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Field Summary
private  boolean	helpHooked           Remembers whether we've hooked the help listener on the control or not.
private  org.eclipse.swt.events.HelpListener	helpListener           Help listener for the control, created lazily when client's first help listener is added.
private  org.eclipse.jface.util.ListenerList	helpListeners           List of help request listeners (element type: org.eclipse.swt.events.HelpListener).
private  java.lang.String[]	keys           The names of this viewer's properties.
private  org.eclipse.jface.util.ListenerList	selectionChangedListeners           List of selection change listeners (element type: ISelectionChangedListener).
private  java.lang.Object[]	values           The values of this viewer's properties.
protected static java.lang.String	WIDGET_DATA_KEY           Unique key for associating element data with widgets.

 

Constructor Summary
protected	Viewer()           Creates a new viewer.

 

Method Summary
void	addHelpListener(org.eclipse.swt.events.HelpListener listener)           Adds a listener for help requests in this viewer.
void	addSelectionChangedListener(ISelectionChangedListener listener)           Adds a listener for selection changes in this selection provider.
protected  void	fireHelpRequested(org.eclipse.swt.events.HelpEvent event)           Notifies any help listeners that help has been requested.
protected  void	fireSelectionChanged(SelectionChangedEvent event)           Notifies any selection changed listeners that the viewer's selection has changed.
abstract  org.eclipse.swt.widgets.Control	getControl()           Returns the primary control associated with this viewer.
java.lang.Object	getData(java.lang.String key)           Returns the value of the property with the given name, or null if the property is not found.
abstract  java.lang.Object	getInput()           Returns the input.
abstract  ISelection	getSelection()           Returns the current selection for this provider.
protected  void	handleHelpRequest(org.eclipse.swt.events.HelpEvent event)           Handles a help request from the underlying SWT control.
protected  void	inputChanged(java.lang.Object input, java.lang.Object oldInput)           Internal hook method called when the input to this viewer is initially set or subsequently changed.
abstract  void	refresh()           Refreshes this viewer completely with information freshly obtained from this viewer's model.
void	removeHelpListener(org.eclipse.swt.events.HelpListener listener)           Removes the given help listener from this viewer.
void	removeSelectionChangedListener(ISelectionChangedListener listener)           Removes the given selection change listener from this selection provider.
org.eclipse.swt.widgets.Item	scrollDown(int x, int y)           Scrolls the viewer's control down by one item from the given display-relative coordinates.
org.eclipse.swt.widgets.Item	scrollUp(int x, int y)           Scrolls the viewer's control up by one item from the given display-relative coordinates.
void	setData(java.lang.String key, java.lang.Object value)           Sets the value of the property with the given name to the given value, or to null if the property is to be removed.
abstract  void	setInput(java.lang.Object input)           Sets or clears the input for this viewer.
void	setSelection(ISelection selection)           The viewer implementation of this ISelectionProvider method make the new selection for this viewer without making it visible.
abstract  void	setSelection(ISelection selection, boolean reveal)           Sets a new selection for this viewer and optionally makes it visible.

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

selectionChangedListeners

private org.eclipse.jface.util.ListenerList selectionChangedListeners

List of selection change listeners (element type: ISelectionChangedListener).

See Also:

fireSelectionChanged(org.eclipse.jface.viewers.SelectionChangedEvent) 55

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helpListeners

private org.eclipse.jface.util.ListenerList helpListeners

List of help request listeners (element type: org.eclipse.swt.events.HelpListener). Help request listeners.

See Also:

handleHelpRequest(org.eclipse.swt.events.HelpEvent) 55

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keys

private java.lang.String[] keys

The names of this viewer's properties. null if this viewer has no properties.

See Also:

setData(java.lang.String, java.lang.Object) 55

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values

private java.lang.Object[] values

The values of this viewer's properties. null if this viewer has no properties. This array parallels the value of the keys field.

See Also:

setData(java.lang.String, java.lang.Object) 55

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helpHooked

private boolean helpHooked

Remembers whether we've hooked the help listener on the control or not.

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helpListener

private org.eclipse.swt.events.HelpListener helpListener

Help listener for the control, created lazily when client's first help listener is added.

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WIDGET_DATA_KEY

protected static final java.lang.String WIDGET_DATA_KEY

Unique key for associating element data with widgets.

See Also:

Widget.setData(String, Object)>Widget.setData(String, Object) 55 , Constant Field Values

Constructor Detail

Viewer

protected Viewer()

Creates a new viewer.

Method Detail

addHelpListener

public void addHelpListener(org.eclipse.swt.events.HelpListener listener)

Adds a listener for help requests in this viewer. Has no effect if an identical listener is already registered.

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addSelectionChangedListener

public void addSelectionChangedListener(ISelectionChangedListener listener)

Description copied from interface: ISelectionProvider

Adds a listener for selection changes in this selection provider. Has no effect if an identical listener is already registered.

Specified by:

addSelectionChangedListener in interface ISelectionProvider

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fireHelpRequested

protected void fireHelpRequested(org.eclipse.swt.events.HelpEvent event)

Notifies any help listeners that help has been requested. Only listeners registered at the time this method is called are notified.

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fireSelectionChanged

protected void fireSelectionChanged(SelectionChangedEvent event)

Notifies any selection changed listeners that the viewer's selection has changed. Only listeners registered at the time this method is called are notified.

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getControl

public abstract org.eclipse.swt.widgets.Control getControl()

Returns the primary control associated with this viewer.

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getData

public java.lang.Object getData(java.lang.String key)

Returns the value of the property with the given name, or null if the property is not found.

The default implementation performs a (linear) search of an internal table. Overriding this method is generally not required if the number of different keys is small. If a more efficient representation of a viewer's properties is required, override both getData and setData.

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getInput

public abstract java.lang.Object getInput()

Description copied from interface: IInputProvider

Returns the input.

Specified by:

getInput in interface IInputProvider

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getSelection

public abstract ISelection getSelection()

Description copied from interface: ISelectionProvider

Returns the current selection for this provider.

Specified by:

getSelection in interface ISelectionProvider

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handleHelpRequest

protected void handleHelpRequest(org.eclipse.swt.events.HelpEvent event)

Handles a help request from the underlying SWT control. The default behavior is to fire a help request, with the event's data modified to hold this viewer.

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inputChanged

protected void inputChanged(java.lang.Object input,
                            java.lang.Object oldInput)

Internal hook method called when the input to this viewer is initially set or subsequently changed.

The default implementation does nothing. Subclassers may override this method to do something when a viewer's input is set. A typical use is populate the viewer.

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refresh

public abstract void refresh()

Refreshes this viewer completely with information freshly obtained from this viewer's model.

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removeHelpListener

public void removeHelpListener(org.eclipse.swt.events.HelpListener listener)

Removes the given help listener from this viewer. Has no affect if an identical listener is not registered.

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removeSelectionChangedListener

public void removeSelectionChangedListener(ISelectionChangedListener listener)

Description copied from interface: ISelectionProvider

Removes the given selection change listener from this selection provider. Has no affect if an identical listener is not registered.

Specified by:

removeSelectionChangedListener in interface ISelectionProvider

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scrollDown

public org.eclipse.swt.widgets.Item scrollDown(int x,
                                               int y)

Scrolls the viewer's control down by one item from the given display-relative coordinates. Returns the newly revealed Item, or null if no scrolling occurred or if the viewer doesn't represent an item-based widget.

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scrollUp

public org.eclipse.swt.widgets.Item scrollUp(int x,
                                             int y)

Scrolls the viewer's control up by one item from the given display-relative coordinates. Returns the newly revealed Item, or null if no scrolling occurred or if the viewer doesn't represent an item-based widget.

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setData

public void setData(java.lang.String key,
                    java.lang.Object value)

Sets the value of the property with the given name to the given value, or to null if the property is to be removed. If this viewer has such a property, its value is replaced; otherwise a new property is added.

The default implementation records properties in an internal table which is searched linearly. Overriding this method is generally not required if the number of different keys is small. If a more efficient representation of a viewer's properties is required, override both getData and setData.

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setInput

public abstract void setInput(java.lang.Object input)

Sets or clears the input for this viewer.

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setSelection

public void setSelection(ISelection selection)

The viewer implementation of this ISelectionProvider method make the new selection for this viewer without making it visible.

This method is equivalent to setSelection(selection,false).

Specified by:

setSelection in interface ISelectionProvider

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setSelection

public abstract void setSelection(ISelection selection,
                                  boolean reveal)

Sets a new selection for this viewer and optionally makes it visible.

Subclasses must implement this method.

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