Bug 89947 [search] polish filters for rules & potential matches
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/search/MatchFilter.java
public boolean filters(JavaElementMatch match) {
		return match.getElement() instanceof IImportDeclaration;
	}
	public String getName() {
		return SearchMessages.MatchFilter_ImportFilter_name; 
	}
	public String getActionLabel() {
		return SearchMessages.MatchFilter_ImportFilter_actionLabel; 
	}
	public String getDescription() {
		return SearchMessages.MatchFilter_ImportFilter_description; 
	}
	
	public boolean isApplicable(JavaSearchQuery query) {
		QuerySpecification spec= query.getSpecification();
		if (spec instanceof ElementQuerySpecification) {
			ElementQuerySpecification elementSpec= (ElementQuerySpecification) spec;
			return elementSpec.getElement() instanceof IType;
		} else if (spec instanceof PatternQuerySpecification) {
			PatternQuerySpecification patternSpec= (PatternQuerySpecification) spec;
			return patternSpec.getSearchFor() == IJavaSearchConstants.TYPE;
		}
		return false;
	}
	public String getID() {
		return "filter_imports"; 
	}
}
abstract class FieldFilter extends MatchFilter {