org.eclipse.jface.text.ITextViewer#getTextOperationTarget ( )源码实例Demo

/**
 * The <code>TextOperationAction</code> implementation of this <code>IUpdate</code> method discovers the operation
 * through the current editor's <code>ITextOperationTarget</code> adapter, and sets the enabled state accordingly.
 */
@Override
public void update() {
	if (!fAllowUpdate)
		return;

	super.update();

	if (!fRunsOnReadOnly && !canModifyViewer()) {
		setEnabled(false);
		return;
	}

	ITextViewer viewer = getTextViewer();
	if (fOperationTarget == null && viewer != null && fOperationCode != -1)
		fOperationTarget = viewer.getTextOperationTarget();

	boolean isEnabled = (fOperationTarget != null && fOperationTarget.canDoOperation(fOperationCode));
	setEnabled(isEnabled);
}
 

@Override
public void update() {
	super.update();
	if (!isEnabled())
		return;

	if (!canModifyViewer()) {
		setEnabled(false);
		return;
	}

	ITextViewer viewer = getTextViewer();
	if (fOperationTarget == null && viewer != null && fOperationCode != -1)
		fOperationTarget = viewer.getTextOperationTarget();

}
 

@Override
public boolean isEnabled(boolean isWritable) {

	if (!isWritable)
		return false;

	/*
	 * Note that this implementation still honors the result returned by canDoOperation.
	 * I.e. if the viewer is set to read-only, this method still returns false.
	 * It covers the case in which the viewer is also writable.
	 *
	 */
	ITextViewer viewer = getTextViewer();
	if (fOperationTarget == null && viewer != null && fOperationCode != -1)
		fOperationTarget = viewer.getTextOperationTarget();

	return (fOperationTarget != null && fOperationTarget.canDoOperation(fOperationCode));
}
 

public TextViewerAction(ITextViewer viewer, int operationCode) {
	this.operationCode = operationCode;
	operationTarget = viewer.getTextOperationTarget();
	update();
}
 

/**
 * Creates a new action.
 * 
 * @param viewer
 *            the viewer
 * @param operationCode
 *            the opcode
 */
public TextViewerAction(ITextViewer viewer, int operationCode) {
	fOperationCode = operationCode;
	fOperationTarget = viewer.getTextOperationTarget();
	update();
}
 

/**
 * Creates a new action.
 *
 * @param viewer the viewer
 * @param operationCode the opcode
 */
public TextViewerAction(ITextViewer viewer, int operationCode) {
	fOperationCode= operationCode;
	fOperationTarget= viewer.getTextOperationTarget();
	update();
}