Names of design patterns appear in small capitals: e.g., ADAPTER. Page numbers in bold indicate the definition of a term. Numbers in italics indicate a diagram for the term. Letters after a diagram's page number indicate the kind of diagram: a "c" denotes a class diagram, an "i" denotes an interaction diagram, and an "o" denotes an object diagram. For example, 88co means that a class and object diagram appears on page 88.

U

undo/redo 59-60, 62-64, 235, 238, 283, 287
avoiding error accumulation during 239
Unidraw
use of ADAPTER 143
use of CHAIN OF RESPONSIBILITY 232
use of COMMAND 232, 242
use of FACTORY METHOD 111
use of ITERATOR 270
use of MEDIATOR 282
use of MEMENTO 289
use of OBSERVER 303
use of PROTOTYPE 126
use of STATE 313
UnsharedConcreteFlyweight
participant of FLYWEIGHT 199
updates
encapsulating complex 299
limiting unexpected 296
protocol for in OBSERVER 296
triggering 297