Bug 89971 [Viewers] Viewers that use IViewerLabelProvider do too many instanceof checks
M6 Checking our viewer the calls to buildLabel are doing too many instanceof checks. As a result certain viewers (such as the table viewer) are twice as slow as they were in 3.0 due to these checks. I have written some performance suites to test the Table, Tree, List and Combo viewers. Table and Tree have this issue.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StructuredViewer.java
}
	}
	/**
	 * Sets the comparator to use for comparing elements, or <code>null</code>
	 * to use the default <code>equals</code> and <code>hashCode</code>
	 * methods on the elements themselves.
	 * 
	 * @param comparer
	 *            the comparator to use for comparing elements or
	 *            <code>null</code>
	 */
	public void setComparer(IElementComparer comparer) {
		this.comparer = comparer;
		if (elementMap != null) {
			elementMap = new CustomHashtable(elementMap, comparer);
		}
	}
	/**
	 * Hook for testing.
	 * @param element
	 * @return Widget
	 */
	public Widget testFindItem(Object element) {
		return findItem(element);
	}
	/**
	 * Removes all elements from the map.
	 * <p>
	 * This method is internal to the framework; subclassers should not call
	 * this method.