### Question:
UnaryFilter extends AbstractFilter { public static UnaryFilter not() { return new UnaryFilter(); } private  UnaryFilter(); static UnaryFilter not(); static UnaryFilter not( Filter filter ); @Override StringBuilder build( StringBuilder builder );  }### Answer:
@Test public void testNot() { AttributeDescriptionFilter attributeFilter = AttributeDescriptionFilter.present( "objectClass" ); assertEquals( "(!" + attributeFilter.build().toString() + ")", UnaryFilter.not( attributeFilter ).build().toString() ); AttributeValueAssertionFilter attributeValueAssertionFilter = AttributeValueAssertionFilter.equal( "objectClass", "person" ); assertEquals( "(!" + attributeValueAssertionFilter.build().toString() + ")", UnaryFilter.not( attributeValueAssertionFilter ).build().toString() ); }