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/*******************************************************************************
* Copyright (c) 2007 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
******************************************************************************/
package org.eclipse.jface.viewers;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Event;
/**
* This class implementation the strategy how the table is navigated using the
* keyboard.
*
* <p>
* <b>Subclasses can implement their custom navigation algorithms</b>
* </p>
*
* @since 3.3
*
*/
public class CellNavigationStrategy {
/**
* is the given event an event which moves the selection to another cell
*
* @param viewer
* the viewer we are working for
* @param event
* the key event
* @return <code>true</code> if a new cell is searched
*/
public boolean isNavigationEvent(ColumnViewer viewer, Event event) {
switch (event.keyCode) {
case SWT.ARROW_UP:
case SWT.ARROW_DOWN:
case SWT.ARROW_LEFT:
case SWT.ARROW_RIGHT:
case SWT.HOME:
case SWT.PAGE_DOWN:
case SWT.PAGE_UP:
case SWT.END:
return true;
default:
return false;
}
}
/**
* @param viewer
* the viewer we are working for
* @param cellToCollapse
* the cell to collapse
* @param event
* the key event
* @return <code>true</code> if this event triggers collapsing of a node
*/
public boolean isCollapseEvent(ColumnViewer viewer,
ViewerCell cellToCollapse, Event event) {
return false;
}
/**
* @param viewer
* the viewer we are working for
* @param cellToExpand
* the cell to expand
* @param event
* the key event
* @return <code>true</code> if this event triggers expanding of a node
*/
public boolean isExpandEvent(ColumnViewer viewer, ViewerCell cellToExpand,
Event event) {
return false;
}
/**
* @param viewer
* the viewer working for
* @param cellToExpand
* the cell the user wants to expand
* @param event
* the event triggering the expansion
*/
public void expand(ColumnViewer viewer, ViewerCell cellToExpand, Event event) {
}
/**
* @param viewer
* the viewer working for
* @param cellToCollapse
* the cell the user wants to collapse
* @param event
* the event triggering the expansion
*/
public void collapse(ColumnViewer viewer, ViewerCell cellToCollapse,
Event event) {
}
/**
* @param viewer
* the viewer we are working for
* @param currentSelectedCell
* the cell currently selected
* @param event
* the key event
* @return the cell which is highlighted next or <code>null</code> if the
* default implementation is taken. E.g. it's fairly impossible to
* react on PAGE_DOWN requests
*/
public ViewerCell findSelectedCell(ColumnViewer viewer,
ViewerCell currentSelectedCell, Event event) {
switch (event.keyCode) {
case SWT.ARROW_UP:
if (currentSelectedCell != null) {
return currentSelectedCell.getNeighbor(ViewerCell.ABOVE, false);
}
break;
case SWT.ARROW_DOWN:
if (currentSelectedCell != null) {
return currentSelectedCell.getNeighbor(ViewerCell.BELOW, false);
}
break;
case SWT.ARROW_LEFT:
if (currentSelectedCell != null) {
return currentSelectedCell.getNeighbor(ViewerCell.LEFT, true);
}
break;
case SWT.ARROW_RIGHT:
if (currentSelectedCell != null) {
return currentSelectedCell.getNeighbor(ViewerCell.RIGHT, true);
}
break;
}
return null;
}
/**
* This method is consulted to decide whether an event has to be canceled or
* not. By default events who collapse/expand tree-nodes are canceled
*
* @param viewer
* the viewer working for
* @param event
* the event
* @return <code>true</code> if the event has to be canceled
*/
public boolean shouldCancelEvent(ColumnViewer viewer, Event event) {
return event.keyCode == SWT.ARROW_LEFT
|| event.keyCode == SWT.ARROW_RIGHT;
}
/**
* This method is called by the framework to initialize this navigation
* strategy object. Subclasses may extend.
*/
protected void init() {
}
}
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