Bug 137849 Unable to set comparator in StructuredViewer
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
*/
	public void setContentProvider(IContentProvider provider) {
		assertContentProviderType(provider);
		super.setContentProvider(provider);
	}
	/**
	 * Assert that the content provider is of one of the
	 * supported types.
	 * @param provider
	 */
	protected void assertContentProviderType(IContentProvider provider) {
		Assert.isTrue(provider instanceof IStructuredContentProvider);
	}
	/*
	 *  (non-Javadoc)
	 * @see org.eclipse.jface.viewers.Viewer#setInput(java.lang.Object)
	 */
	public final void setInput(Object input) {
		try {
			
			unmapAllElements();
			super.setInput(input);
		} finally {
			
		}
	}
	/*
	 *  (non-Javadoc)
	 * @see org.eclipse.jface.viewers.Viewer#setSelection(org.eclipse.jface.viewers.ISelection, boolean)
	 */