Sun Certified Enterprise Architect for Java EE Study Guide

Acknowledgments . . . xv

About the Authors . . . xvii

Chapter 1 What Is Architecture? . . . 1

Introduction . . . 1

Prerequisite Review . . . 1

Discussion . . . 2

Understanding Architecture . . . 2

Role of the Architect . . . 5

More Detail on the Exam Itself . . . 6

Part I: Multiple Choice . . . 7

Part II: Solving the Business Problem . . . 8

Part III: Defending Your Solution . . . 9

Preparing for the Exam . . . 10

Preparing for Part I . . . 10

Preparing for Part II . . . 11

Preparing for Part III . . . 11

Essential Points . . . 11

Review Your Progress . . . 11

Chapter 2 Architecture Decomposition . . . 13

Introduction . . . 13

Prerequisite Review . . . 14

Discussion . . . 14

Decomposition Strategies . . . 14

Layering . . . 15

Distribution . . . 15

Exposure . . . 16

Functionality . . . 16

Generality . . . 16

Coupling and Cohesion . . . 16

Volatility . . . 16

Configuration . . . 16

Planning and Tracking . . . 17

Work Assignment . . . 17

Tiers . . . 17

Client . . . 17

Web . . . 18

Business . . . 18

Integration . . . 18

Resource . . . 18

Layers . . .18

Application . . . 19

Virtual Platform (Component APIs) . . . 19

Application Infrastructure (Containers) . . . 19

Enterprise Services (OS and Virtualization) . . . 19

Compute and Storage . . . 19

Networking Infrastructure . . . 20

Service-Level Requirements . . . 20

Performance . . . 20

Scalability . . . 20

Reliability . . . 21

Availability . . . 21

Extensibility . . . 22

Maintainability . . . 22

Manageability . . . 22

Security . . . 22

Impact of Dimensions on Service-Level Requirements . . . 23

Capacity . . . 23

Redundancy . . . 23

Modularity . . . 23

Tolerance . . . 24

Workload . . . 24

Heterogeneity . . . 24

Common Practices for Improving Service-Level Requirements . . . 24

Introducing Redundancy to the System Architecture . . . 24

Improving Performance . . . 27

Improving Availability . . . 28

Improving Extensibility . . . 29

Improving Scalability . . . 30

Tiers in Architecture . . . 30

Two-Tier Systems . . . 31

Advantages . . . 31

Disadvantages . . . 31

Three- and Multi-Tier Systems . . . 31

Advantages . . . 32

Disadvantages . . . 32

Essential Points . . . 32

Review Your Progress . . . 33

Chapter 3 Web Tier Technologies . . . 35

Introduction . . . 35

Prerequisite Review . . . 36

Model View Controller (MVC) . . . 36

Web Container . . . 36

Servlets . . . 37

Filters . . . 38

Listeners . . . 39

JavaServer Pages (JSP) . . . 39

Java Standard Tag Library (JSTL) . . . 40

Unified Expression Language (EL) . . . 40

Managing Sessions . . . 40

JavaServer Faces (JSF) . . . 41

Templating Frameworks . . . 41

Web Frameworks . . . 42

Discussion . . . 42

JSPs and Servlets-Standard Uses . . . 42

JSF-Standard Uses . . . 43

Web-Centric Implementations . . . 43

EJB-Centric Implementations . . . 44

Rationale for Choosing Between EJB-Centric and Web-Centric Implementations . . . 45

The Future of Client-Server Communication . . . 46

Essential Points . . . 46

Review Your Progress . . . 47

Chapter 4 Business Tier Technologies . . . 51

Introduction . . . 51

Prerequisite Review . . . 52

Enterprise Java Bean . . . 53

Session Bean . . . 54

Stateless Session Bean . . . 54

Stateful Session Bean . . . 55

Entity Beans . . . 56

CMP Entity Bean . . . 56

BMP Entity Bean . . . 57

Entity Class . . . 57

Persistence Strategies . . . 58

Message-Driven Bean . . . 58

Discussion . . . 59

EJB Advantages and Disadvantages . . . 59

Scalability . . . 59

Security . . . 60

Contrasting Persistence Strategies . . . 60

Ease of Development . . . 60

Performance . . . 60

Extensibility . . . 61

EJB and Web Services . . . 61

EJBs as Web Service End Points . . . 61

EJBs Consuming Web Services . . . 61

Advantages and Disadvantages . . . 62

EJB 3 . . . 62

Ease of Development . . . 63

Container in EJB 3 . . . 63

JPA in EJB 3 . . . 63

Essential Points . . . 64

Review Your Progress . . . 65

Chapter 5 Integration and Messaging . . . 69

Introduction . . . 69

Prerequisite Review . . . 70

Web Services . . . 71

SOAP . . . 71

WSDL . . . 72

JAX-RPC . . . 72

JAX-WS . . . 72

JAXB . . . 72

JAXR . . . 73

JMS . . . 73

JCA . . . 74

Discussion . . . 75

Java to Java Integration . . . 75

Java Messaging Service (JMS) . . . 76

Java to Non-Java Integration . . . 76

Web Services . . . 76

Java Connector Architecture (JCA) . . . 77

Essential Points . . . 78

Review Your Progress . . . 78

Chapter 6 Security . . . 83

Introduction . . . 83

Prerequisite Review . . . 84

JRE . . . 85

JAAS . . . 85

Credential . . . 85

Principal . . . 86

Authentication . . . 86

Authorization . . . 86

Discussion . . . 86

Client-Side Security . . . 87

Server-Side Security . . . 88

EJB Container . . . 88

Web Container . . . 88

Putting the EJB Container and Web Container Together . . . 89

Web Service Security . . . 90

How Security Behavior Is Defined . . . 91

Declarative Security . . . 91

Programmatic Security . . . 92

Commonly Encountered Security Threats . . . 93

Defining a Security Model . . . 94

Essential Points . . . 95

Review Your Progress . . . 95

Chapter 7 Applying Patterns . . . 99

Introduction . . . 99

Prerequisite Review . . . 100

Discussion . . . 101

Creational Patterns . . . 101

Abstract Factory Pattern . . . 101

Builder Pattern . . . 103

Factory Method Pattern . . . 104

Prototype Pattern . . . 105

Singleton Pattern . . . 106

Structural Patterns . . . 107

Adapter Pattern . . . 107

Bridge Pattern . . . 108

Composite Pattern . . . 109

Decorator Pattern . . . 111

Facade Pattern . . . 112

Flyweight Pattern . . . 113

Proxy Pattern . . . 114

Behavioral Patterns . . . 115

Chain of Responsibility Pattern . . . 115

Command Pattern . . . 116

Interpreter Pattern . . . 117

Iterator Pattern . . . 118

Mediator Pattern . . . 119

Memento Pattern . . . 120

Observer Pattern . . . 121

State Pattern . . . 122

Strategy Pattern . . . 123

Template Method Pattern . . . 124

Visitor Pattern . . . 125

Core Java EE Patterns . . . 126

Presentation Tier . . . 126

Intercepting Filter . . . 126

Context Object . . . 127

Front Controller . . . 128

Application Controller . . . 129

View Helper . . . 129

Composite View . . . 130

Dispatcher View . . . 131

Service to Worker . . . 132

Business Tier . . . 132

Business Delegate . . . 133

Service Locator . . . 133

Session Facade . . . 134

Application Service . . . 135

Business Object . . . 136

Composite Entity . . . 136

Transfer Object . . . 137

Transfer Object Assembler . . . 138

Value List Handler . . . 139

Integration Tier . . . 139

Data Access Object . . . 140

Service Activator . . . 140

Domain Store . . . 141

Web Service Broker . . . 142

Essential Points . . . 143

Review Your Progress . . . 146

Chapter 8 Documenting an Architecture . . . 149

Introduction . . . 149

Prerequisite Review . . . 149

Discussion . . . 150

Building Blocks of UML . . . 150

Elements . . . 151

Structural Elements . . . 151

Behavioral Elements . . . 152

Grouping Element . . . 153

Annotational Elements . . . 153

Relationships . . . 154

Common Mechanisms . . . 155

Specifications . . . 155

Adornments . . . 155

Common Divisions . . . 156

Extensibility Mechanisms . . . 156

UML Diagrams . . . 157

Structure Diagrams . . . 157

Class Diagram . . . 157

Component Diagram . . . 157

Deployment Diagram . . . 159

Package Diagram . . . 159

Behavior Diagrams . . . 160

Activity Diagram . . . 160

Statechart Diagram . . . 161

Use-Case Diagram . . . 162

Interaction Diagrams . . . 163

Essential Points . . . 164

Review Your Progress . . . 164

Chapter 9 Tackling Parts II and III . . . 167

Introduction . . . 167

Prerequisite Review . . . 167

Discussion . . . 168

Scenario . . . 168

Worked Solution . . . 170

Class Diagram . . . 170

Component Diagram . . . 173

Deployment Diagram . . . 174

Sequence Diagrams . . . 176

Comments on Diagrams . . . 178

Identified Risks and Mitigations . . . 178

Part III-Defending Your Architecture . . . 179

Essential Points . . . 180

Index . . . 181