Throws an <code>SWTException</code> if the receiver can not
be accessed by the caller. This may include both checks on
the state of the receiver and more generally on the entire
execution context. This method <em>should</em> be called by
device implementors to enforce the standard SWT invariants.
<p>
Currently, it is an error to invoke any method (other than
<code>isDisposed()</code> and <code>dispose()</code>) on a
device that has had its <code>dispose()</code> method called.
</p><p>
In future releases of SWT, there may be more or fewer error
checks and exceptions may be thrown for different reasons.
<p>
@exception SWTException <ul>
<li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
</ul>
Throws an <code>SWTException</code> if the receiver can not be accessed by the caller. This may include both checks on the state of the receiver and more generally on the entire execution context. This method <em>should</em> be called by device implementors to enforce the standard SWT invariants. <p> Currently, it is an error to invoke any method (other than <code>isDisposed()</code> and <code>dispose()</code>) on a device that has had its <code>dispose()</code> method called. </p><p> In future releases of SWT, there may be more or fewer error checks and exceptions may be thrown for different reasons. <p>
@exception SWTException <ul> <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> </ul>