Pub-Sub Pattern Initialization Indirect Communication: Publisher- Subscriber
5.2.2 Proxy
Proxy is needed when the logistics of accessing another object’s services sending messages to it is overly complex and requires great expertise. In such cases, the code surrounding the other object’s method invocation becomes comparable or even greater in size than the code of the object’s primary expertise. Instead of making the client object invoker more complex, we can introduce a proxy of the server object subject, see Figure 5-10. Proxy is a surrogate used to stand in for the actual subject object and controlenhance access to it. The causes of access complexity include: • Receiver is located in a remote address space, e.g., on a remote host, in which case the invocation requires following complex networking protocols • Receiver access should be filtered for security purposes or to enforce certain constraints, such as an upper limit on the number of accesses a b ActionType1Cmd + execute + unexecute + isReversible ActionType2Cmd + execute + unexecute + isReversible Receiver1 + doAction1 Receiver2 + doAction2 Invoker Invoker «interface» Command + execute + unexecute + isReversible : boolean receiver receiver Command Knowing Responsibilities: • Knows receiver of action request • Knows whether action is reversible Doing Responsibilities: • Executes an action • Undoes a reversible action Figure 5-8: a Command object employee card. b The Command design pattern class diagram. The base Command class is usually implemented as an interface.Parts
» | Komputasi | Suatu Permulaan
» Why Software Engineering Is Difficult
» Book Organization What is Software Engineering?
» Symbol Language Software Engineering Lifecycle
» Requirements Analysis and System Specification
» Object-Oriented Analysis and the Domain Model
» Object-Oriented Design Software Engineering Lifecycle
» Case Study 1: From Home Access Control to Adaptive Homes
» Case Study 2: Personal Investment Assistant
» Relationships and Communication Object Model
» Design of Objects Object Model
» PROPHASE 2. METAPHASE TELOPHASE 3. ANAPHASE
» Project 2: Restaurant Automation Student Team Projects
» Stock Market Investment Fantasy League
» Web-based Stock Forecasters Student Team Projects
» Summary and Bibliographical Notes
» Agile Development Software Development Methods
» Types of Requirements Requirements Analysis and Use Cases
» Use Cases Requirements Analysis and Use Cases
» Requirements Elicitation through Use Cases
» Modeling System Workflows Requirements Analysis and Use Cases
» Why Software Engineering Is Difficult 1
» Identifying Concepts Analysis: Building the Domain Model
» Concept Associations and Attributes
» Contracts: Preconditions and Postconditions
» Design Principles for Assigning Responsibilities
» Class Diagram Design: Assigning Responsibilities
» Why Software Engineering Is Difficult 2
» Software Architecture | Komputasi | Suatu Permulaan
» Implementation | Komputasi | Suatu Permulaan
» World Phenomena and Their Abstractions
» Events, Signals, and Messages
» Context Diagrams and Domains
» Systems and System Descriptions
» Basic Formalisms for Specifications
» UML Object Constraint Language OCL
» TLA+ Notation Notations for System Specification
» Problem Frame Notation Problem Frames
» Problem Decomposition into Frames
» Composition of Problem Frames
» Specifying Goals Summary and Bibliographical Notes
» Measurement Theory Fundamentals of Measurement Theory
» What to Measure? | Komputasi | Suatu Permulaan
» Cyclomatic Complexity Measuring Complexity
» Internal Cohesion or Syntactic Cohesion
» Semantic Cohesion Measuring Module Cohesion
» Algorithmic Information Content Psychological Complexity
» Applications of Publisher-Subscriber Indirect Communication: Publisher- Subscriber
» Control Flow Indirect Communication: Publisher- Subscriber
» Pub-Sub Pattern Initialization Indirect Communication: Publisher- Subscriber
» Exclusive Resource Access—Exclusion Synchronization
» Cooperation between Threads—Condition
» Concurrent Programming Example Concurrent Programming
» Broker Pattern Broker and Distributed Computing
» Java Remote Method Invocation RMI
» Symmetric and Public-Key Cryptosystems
» Release publicly the public key, which is the pair of numbers n and E, K
» Syntax Structure of XML Documents
» Document Type Definition DTD
» Namespaces Structure of XML Documents
» XML Parsers Structure of XML Documents
» XML Schema Basics XML Schemas
» Models for Structured Content
» XPointer and Xpath Indexing and Linking
» Document Transformation and XSL
» Components, Ports, and Events
» Property Access Event Firing
» Custom Methods JavaBeans: Interaction with Components
» Run-Time Type Identification Computational Reflection
» Automatic Component Binding Computational Reflection
» State Persistence for Transport
» Port Interconnections A Component Framework
» Levels of A Component Framework
» Service Oriented Architecture | Komputasi | Suatu Permulaan
» The SOAP Section 5 Encoding Rules
» SOAP Communication SOAP Communication Protocol
» Binding SOAP to a Transport Protocol
» The WSDL 2.0 Building Blocks
» Defining a Web Service’s Abstract Interface
» Binding a Web Service Implementation
» Using WSDL to Generate SOAP Binding
» Non-functional Descriptions and Beyond WSDL
» UDDI for Service Discovery and Integration
» Server-side Development with Axis
» Client-side Development with Axis
» OMG Reusable Asset Specification Summary and Bibliographical Notes
» Aspect-Oriented Programming | Komputasi | Suatu Permulaan
» OMG MDA | Komputasi | Suatu Permulaan
» Autonomic Computing | Komputasi | Suatu Permulaan
» Software-as-a-Service SaaS End User Software Development
Show more