Bug 161738 [Undo] - API - promote ability to quietly compute status to operations API
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/undo/AbstractWorkspaceOperation.java
* @param quiet
	 *            <code>true</code> if it is inappropriate to consult the user
	 *            while computing status, and <code>false</code> if the user
	 *            may be consulted.
	 * 
	 * @see #computeExecutionStatus(IProgressMonitor)
	 * @see #computeUndoableStatus(IProgressMonitor)
	 * @see #computeRedoableStatus(IProgressMonitor)
	 */
	public void setQuietCompute(boolean quiet) {
		quietCompute = quiet;
	}
	/*
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		StringBuffer text = new StringBuffer(super.toString());
		text.append("\n"); 
		text.append(this.getClass().getName());
		appendDescriptiveText(text);
		return text.toString();
	}
	/**
	 * Append any descriptive text to the specified string buffer to be shown in
	 * the receiver's {@link #toString()} text.
	 * 
	 * @param text
	 *            the StringBuffer on which to append the text
	 */
	protected void appendDescriptiveText(StringBuffer text) {