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/*******************************************************************************
* Copyright (c) 2012, 2013, 2014 Original authors 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:
* Original authors and others - initial API and implementation
* Dirk Fauth - added ITraversalStrategy handling
******************************************************************************/
package org.eclipse.nebula.widgets.nattable.selection;
import org.eclipse.nebula.widgets.nattable.command.ILayerCommand;
import org.eclipse.nebula.widgets.nattable.command.ILayerCommandHandler;
import org.eclipse.nebula.widgets.nattable.layer.ILayer;
import org.eclipse.nebula.widgets.nattable.selection.SelectionLayer.MoveDirectionEnum;
import org.eclipse.nebula.widgets.nattable.selection.command.MoveSelectionCommand;
/**
* Abstraction of the selection behavior during navigation in the grid.
* Implementations of this class specify what to select when the selection moves
* by responding to the {@link MoveSelectionCommand}.
*
* @param <T>
* The type of the {@link ILayerCommand} this
* {@link ILayerCommandHandler} handles. Needs to be a
* {@link MoveSelectionCommand} or subtype.
*
* @see MoveCellSelectionCommandHandler
* @see MoveRowSelectionCommandHandler
*/
public abstract class MoveSelectionCommandHandler<T extends MoveSelectionCommand> implements ILayerCommandHandler<T> {
/**
* The SelectionLayer instance which is needed to perform selection
* operations.
*/
protected final SelectionLayer selectionLayer;
/**
* The strategy to use on traversal. Specifies the behavior when the
* movement reaches a border.
*/
protected final ITraversalStrategy traversalStrategy;
/**
* Create a MoveSelectionCommandHandler for the given {@link SelectionLayer}
* . Uses the {@link ITraversalStrategy#AXIS_TRAVERSAL_STRATEGY} as default
* strategy for selection movement.
*
* @param selectionLayer
* The {@link SelectionLayer} on which the selection should be
* performed.
*/
public MoveSelectionCommandHandler(SelectionLayer selectionLayer) {
this(selectionLayer, ITraversalStrategy.AXIS_TRAVERSAL_STRATEGY);
}
/**
* Create a MoveSelectionCommandHandler for the given {@link SelectionLayer}
* .
*
* @param selectionLayer
* The {@link SelectionLayer} on which the selection should be
* performed.
* @param traversalStrategy
* The strategy that should be used for selection movements. Can
* not be <code>null</code>.
*/
public MoveSelectionCommandHandler(SelectionLayer selectionLayer, ITraversalStrategy traversalStrategy) {
if (traversalStrategy == null) {
throw new IllegalArgumentException("You need to specify an ITraversalStrategy!"); //$NON-NLS-1$
}
this.selectionLayer = selectionLayer;
this.traversalStrategy = traversalStrategy;
}
@Override
public boolean doCommand(ILayer targetLayer, T command) {
if (command.convertToTargetLayer(this.selectionLayer)) {
moveSelection(command.getDirection(), getTraversalStrategy(command),
command.isShiftMask(), command.isControlMask());
return true;
}
return false;
}
/**
* Determines the {@link ITraversalStrategy} that should be used to move the
* selection on handling the given command. The strategy is determined in
* the following way:
* <ol>
* <li>Return the {@link ITraversalStrategy} carried by the command</li>
* <li>If it doesn't contain a {@link ITraversalStrategy} but a carries a
* dedicated step count, create a temporary {@link ITraversalStrategy} that
* is configured with the locally configured {@link ITraversalStrategy} but
* returns the step count carried by the command.</li>
* <li>If the command doesn't carry a {@link ITraversalStrategy} and no
* dedicated step count, the {@link ITraversalStrategy} registered with this
* command handler is returned.</li>
* </ol>
*
* @param command
* The current handled command.
* @return The {@link ITraversalStrategy} that should be used to move the
* selection.
*/
protected ITraversalStrategy getTraversalStrategy(final T command) {
// if the command comes with a strategy we use it
ITraversalStrategy result = command.getTraversalStrategy();
if (result == null) {
if (command.getStepSize() != null) {
// command carries a step size, so we use the internal strategy
// with the transported step size this is mainly for backwards
// compatibility
result = new ITraversalStrategy() {
@Override
public TraversalScope getTraversalScope() {
return MoveSelectionCommandHandler.this.traversalStrategy.getTraversalScope();
}
@Override
public boolean isCycle() {
return MoveSelectionCommandHandler.this.traversalStrategy.isCycle();
}
@Override
public int getStepCount() {
return command.getStepSize();
}
};
}
else {
result = this.traversalStrategy;
}
}
return result;
}
/**
* Moves the selection from the current position into the given move
* direction.
*
* @param moveDirection
* The direction to move to.
* @param traversalStrategy
* the traversal strategy to determine the number of steps to
* move and the behavior on moving over the border
* @param withShiftMask
* boolean flag to indicate whether the shift key modifier is
* enabled or not
* @param withControlMask
* boolean flag to indicate whether the control key modifier is
* enabled or not
*/
protected void moveSelection(MoveDirectionEnum moveDirection, ITraversalStrategy traversalStrategy,
boolean withShiftMask, boolean withControlMask) {
switch (moveDirection) {
case UP:
moveLastSelectedUp(traversalStrategy, withShiftMask, withControlMask);
break;
case DOWN:
moveLastSelectedDown(traversalStrategy, withShiftMask, withControlMask);
break;
case LEFT:
moveLastSelectedLeft(traversalStrategy, withShiftMask, withControlMask);
break;
case RIGHT:
moveLastSelectedRight(traversalStrategy, withShiftMask, withControlMask);
break;
default:
break;
}
}
/**
* Moves the selection from the current position to the right.
*
* @param traversalStrategy
* the traversal strategy to determine the number of steps to
* move and the behavior on moving over the border
* @param withShiftMask
* boolean flag to indicate whether the shift key modifier is
* enabled or not
* @param withControlMask
* boolean flag to indicate whether the control key modifier is
* enabled or not
*/
protected abstract void moveLastSelectedRight(ITraversalStrategy traversalStrategy,
boolean withShiftMask, boolean withControlMask);
/**
* Moves the selection from the current position to the left.
*
* @param traversalStrategy
* the traversal strategy to determine the number of steps to
* move and the behavior on moving over the border
* @param withShiftMask
* boolean flag to indicate whether the shift key modifier is
* enabled or not
* @param withControlMask
* boolean flag to indicate whether the control key modifier is
* enabled or not
*/
protected abstract void moveLastSelectedLeft(ITraversalStrategy traversalStrategy,
boolean withShiftMask, boolean withControlMask);
/**
* Moves the selection from the current position up.
*
* @param traversalStrategy
* the traversal strategy to determine the number of steps to
* move and the behavior on moving over the border
* @param withShiftMask
* boolean flag to indicate whether the shift key modifier is
* enabled or not
* @param withControlMask
* boolean flag to indicate whether the control key modifier is
* enabled or not
*/
protected abstract void moveLastSelectedUp(ITraversalStrategy traversalStrategy,
boolean withShiftMask, boolean withControlMask);
/**
* Moves the selection from the current position down.
*
* @param traversalStrategy
* the traversal strategy to determine the number of steps to
* move and the behavior on moving over the border
* @param withShiftMask
* boolean flag to indicate whether the shift key modifier is
* enabled or not
* @param withControlMask
* boolean flag to indicate whether the control key modifier is
* enabled or not
*/
protected abstract void moveLastSelectedDown(ITraversalStrategy traversalStrategy,
boolean withShiftMask, boolean withControlMask);
}
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