文档介绍：Motivation
Design P atterns and F ramew o rks
fo r Object-o riente d
Developing ecient , robust , extensible , and
Communicatio n Systems
munication soft w a re is ha rd
It is essential to understand essful tech-
Douglas C. Schmidt
niques that have p roven e ective to solve
common development challenges
.ed u/ s chmi dt/
Design patterns and framew o rks help to cap-
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ture, a rticulate, and instantiate these suc-
cessful techniques
W ashington Universit y , St. Louis
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Observations
Design P atterns
Develop ers munication soft w a re con-
Design patterns rep resent solutions to p rob-
front recurring challenges that a re la rgely
lems that a rise when developing soft w a re
application-indep endent
within a pa rticula r context
{ . , service initiali za tion and distribution, erro r
{ . ,\P atterns == p roblem/solution pairs in a con-
handling,
o w control, event demultipl exing, con-
text"
currency control
P atterns capture the static and dynamic struc-
essful develop ers resolve these challenges
ture and collab o ration among k ey pa rtici-
pants in soft w a re designs
b y applying app rop riate design patterns
{ They a re pa rticula r ly useful fo r a rticulating ho w
and why to resolve non-functional fo rces
Ho w ever, these patterns have traditionally
b een either:
1. Lo ck ed inside heads of exp ert develop ers
P atterns facilitate reuse of essful soft-
w a re a rchitectures and designs
2. Buried in source co de
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Pro xy P attern
Graphical Notation
1: METHOD
: BROKER CALL
: QUOTER
4: METHOD OBJECT
PROXY
RETURN PROCESS : CLASS
2: FORWARD THREAD
REQUEST
3: RESPONSE
CLASS
CLIENT CLASS TEMPLATE UTILITY
: QUOTER CLASS
NETWORK
CLASS
CATEGORY INHERITS INSTANTIATES
SERVER
ABSTRACT
CLASS
A CONTAINS USES
Intent : p rovide a surrogate fo r another ob-
ject that controls access to it
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