Frank Buschmann, Siemens AG, Germany Kevlin Henney, Curbralan, Bristol, UK Douglas C. Schmidt, Vanderbilt University, Nashville, Tennessee, USA

• Foreword xvAbout This Book xviiAbout The Authors xxiiiGuide To The Reader xxviiPart I Some Concepts 11 On Patterns and Pattern Languages 31.1 Patterns Introduced 41.2 Inside Patterns 61.3 Between Patterns 101.4 Into Pattern Languages 131.5 Patterns Connected 152 On Distributed Systems 172.1 Benefits of Distribution 182.2 Challenges of Distribution 202.3 Technologies for Supporting Distribution 222.4 Limitations of Middleware 323 On the Pattern Language 333.1 Intent, Scope, and Audience 343.2 Origins and Genesis 353.3 Structure and Content 363.4 Presentation 443.5 Practical Use 49Part II A Story 534 Warehouse Management Process Control 574.1 System Scope 584.2 Warehouse Management Process Control 605 Baseline Architecture 655.1 Architecture Context 665.2 Partitioning the Big Ball of Mud 675.3 Decomposing the Layers 685.4 Accessing Domain Object Functionality 715.5 Bridging the Network 725.6 Separating User Interfaces 765.7 Distributing Functionality 795.8 Supporting Concurrent Domain Object Access 825.9 Achieving Scalable Concurrency 855.10 Crossing the Object-Oriented/Relational Divide 875.11 Configuring Domain Objects at Runtime 895.12 Baseline Architecture Summary 906 Communication Middleware 956.1 A Middleware Architecture for Distributed Systems 966.2 Structuring the Internal Design of the Middleware 1006.3 Encapsulating Low-level System Mechanisms 1036.4 Demultiplexing ORB Core Events 1056.5 Managing ORB Connections 1086.6 Enhancing ORB Scalability 1116.7 Implementing a Synchronized Request Queue 1146.8 Interchangeable Internal ORB Mechanisms 1166.9 Consolidating ORB Strategies 1186.10 Dynamic Configuration of ORBs 1216.11 Communication Middleware Summary 1247 Warehouse Topology 1297.1 Warehouse Topology Baseline 1307.2 Representing Hierarchical Storage 1317.3 Navigating the Storage Hierarchy 1337.4 Modeling Storage Properties 1357.5 Varying Storage Behavior 1377.6 Realizing Global Functionality 1407.7 Traversing the Warehouse Topology 1427.8 Supporting Control Flow Extensions 1447.9 Connecting to the Database 1467.10 Maintaining In-Memory Storage Data 1477.11 Configuring the Warehouse Topology 1497.12 Detailing the Explicit Interface 1517.13 Warehouse Topology Summary 1538 The Story Behind The Pattern Story 157Part III The Language 1639 From Mud To Structure 167Domain Model ** 182Layers ** 185Model-View-Controller ** 188Presentation-Abstraction-Control 191Microkernel ** 194Reflection * 197Pipes and Filters ** 200Shared Repository ** 202Blackboard 205Domain Object ** 20810 Distribution Infrastructure 211Messaging ** 221Message Channel ** 224Message Endpoint ** 227Message Translator ** 229Message Router ** 231Publisher-Subscriber ** 234Broker ** 237Client Proxy ** 240Requestor ** 242Invoker ** 244Client Request Handler ** 246Server Request Handler ** 24911 Event Demultiplexing and Dispatching 253Reactor ** 259Proactor * 262Acceptor-Connector ** 265Asynchronous Completion Token ** 26812 Interface Partitioning 271Explicit Interface ** 281Extension Interface ** 284Introspective Interface ** 286Dynamic Invocation Interface * 288Proxy ** 290Business Delegate ** 292Facade ** 294Combined Method ** 296Iterator ** 298Enumeration Method ** 300Batch Method ** 30213 Component Partitioning 305Encapsulated Implementation ** 313Whole-Part ** 317Composite ** 319Master-Slave * 321Half-Object plus Protocol ** 324Replicated Component Group * 32614 Application Control 329Page Controller ** 337Front Controller ** 339Application Controller ** 341Command Processor ** 343Template View ** 345Transform View ** 347Firewall Proxy ** 349Authorization ** 35115 Concurrency 353Half-Sync/Half-Async ** 359Leader/Followers ** 362Active Object ** 365Monitor Object ** 36816 Synchronization 371Guarded Suspension ** 380Future ** 382Thread-Safe Interface * 384Double-Checked Locking 386Strategized Locking ** 388Scoped Locking ** 390Thread-Specific Storage 392Copied Value ** 394Immutable Value ** 39617 Object Interaction 399Observer ** 405Double Dispatch ** 408Mediator * 410Command ** 412Memento ** 414Context Object ** 416Data Transfer Object ** 418Message ** 42018 Adaptation and Extension 423Bridge ** 436Object Adapter ** 438Chain of Responsibility * 440Interpreter 442Interceptor ** 444Visitor ** 447Decorator 449Execute-Around Object ** 451Template Method * 453Strategy ** 455Null Object ** 457Wrapper Facade ** 459Declarative Component Configuration * 46119 Modal Behavior 463Objects for States * 467Methods for States * 469Collections for States ** 47120 Resource Management 473Container * 488Component Configurator * 490Object Manager ** 492Lookup ** 495Virtual Proxy ** 497Lifecycle Callback ** 499Task Coordinator * 501Resource Pool ** 503Resource Cache ** 505Lazy Acquisition ** 507Eager Acquisition ** 509Partial Acquisition * 511Activator ** 513Evictor ** 515Leasing ** 517Automated Garbage Collection ** 519Counting Handle ** 522Abstract Factory ** 525Builder * 527Factory Method ** 529Disposal Method ** 53121 Database Access 533Database Access Layer ** 538Data Mapper ** 540Row Data Gateway ** 542Table Data Gateway ** 544Active Record 54622 A Departing Thought 549Glossary 553References 573Index of Patterns 587Index of Names 593Subject Index 595

"The authors' decision to include a real-life use case was a good strategy it illustrate the application of the pattern language." (Computing Reviews, February 15, 2008)

Frank Buschmann, Siemens AG, Germany Kevlin Henney, Curbralan, Bristol, UK Douglas C. Schmidt, Vanderbilt University, Nashville, Tennessee, USA

• Foreword xvAbout This Book xviiAbout The Authors xxiiiGuide To The Reader xxviiPart I Some Concepts 11 On Patterns and Pattern Languages 31.1 Patterns Introduced 41.2 Inside Patterns 61.3 Between Patterns 101.4 Into Pattern Languages 131.5 Patterns Connected 152 On Distributed Systems 172.1 Benefits of Distribution 182.2 Challenges of Distribution 202.3 Technologies for Supporting Distribution 222.4 Limitations of Middleware 323 On the Pattern Language 333.1 Intent, Scope, and Audience 343.2 Origins and Genesis 353.3 Structure and Content 363.4 Presentation 443.5 Practical Use 49Part II A Story 534 Warehouse Management Process Control 574.1 System Scope 584.2 Warehouse Management Process Control 605 Baseline Architecture 655.1 Architecture Context 665.2 Partitioning the Big Ball of Mud 675.3 Decomposing the Layers 685.4 Accessing Domain Object Functionality 715.5 Bridging the Network 725.6 Separating User Interfaces 765.7 Distributing Functionality 795.8 Supporting Concurrent Domain Object Access 825.9 Achieving Scalable Concurrency 855.10 Crossing the Object-Oriented/Relational Divide 875.11 Configuring Domain Objects at Runtime 895.12 Baseline Architecture Summary 906 Communication Middleware 956.1 A Middleware Architecture for Distributed Systems 966.2 Structuring the Internal Design of the Middleware 1006.3 Encapsulating Low-level System Mechanisms 1036.4 Demultiplexing ORB Core Events 1056.5 Managing ORB Connections 1086.6 Enhancing ORB Scalability 1116.7 Implementing a Synchronized Request Queue 1146.8 Interchangeable Internal ORB Mechanisms 1166.9 Consolidating ORB Strategies 1186.10 Dynamic Configuration of ORBs 1216.11 Communication Middleware Summary 1247 Warehouse Topology 1297.1 Warehouse Topology Baseline 1307.2 Representing Hierarchical Storage 1317.3 Navigating the Storage Hierarchy 1337.4 Modeling Storage Properties 1357.5 Varying Storage Behavior 1377.6 Realizing Global Functionality 1407.7 Traversing the Warehouse Topology 1427.8 Supporting Control Flow Extensions 1447.9 Connecting to the Database 1467.10 Maintaining In-Memory Storage Data 1477.11 Configuring the Warehouse Topology 1497.12 Detailing the Explicit Interface 1517.13 Warehouse Topology Summary 1538 The Story Behind The Pattern Story 157Part III The Language 1639 From Mud To Structure 167Domain Model ** 182Layers ** 185Model-View-Controller ** 188Presentation-Abstraction-Control 191Microkernel ** 194Reflection * 197Pipes and Filters ** 200Shared Repository ** 202Blackboard 205Domain Object ** 20810 Distribution Infrastructure 211Messaging ** 221Message Channel ** 224Message Endpoint ** 227Message Translator ** 229Message Router ** 231Publisher-Subscriber ** 234Broker ** 237Client Proxy ** 240Requestor ** 242Invoker ** 244Client Request Handler ** 246Server Request Handler ** 24911 Event Demultiplexing and Dispatching 253Reactor ** 259Proactor * 262Acceptor-Connector ** 265Asynchronous Completion Token ** 26812 Interface Partitioning 271Explicit Interface ** 281Extension Interface ** 284Introspective Interface ** 286Dynamic Invocation Interface * 288Proxy ** 290Business Delegate ** 292Facade ** 294Combined Method ** 296Iterator ** 298Enumeration Method ** 300Batch Method ** 30213 Component Partitioning 305Encapsulated Implementation ** 313Whole-Part ** 317Composite ** 319Master-Slave * 321Half-Object plus Protocol ** 324Replicated Component Group * 32614 Application Control 329Page Controller ** 337Front Controller ** 339Application Controller ** 341Command Processor ** 343Template View ** 345Transform View ** 347Firewall Proxy ** 349Authorization ** 35115 Concurrency 353Half-Sync/Half-Async ** 359Leader/Followers ** 362Active Object ** 365Monitor Object ** 36816 Synchronization 371Guarded Suspension ** 380Future ** 382Thread-Safe Interface * 384Double-Checked Locking 386Strategized Locking ** 388Scoped Locking ** 390Thread-Specific Storage 392Copied Value ** 394Immutable Value ** 39617 Object Interaction 399Observer ** 405Double Dispatch ** 408Mediator * 410Command ** 412Memento ** 414Context Object ** 416Data Transfer Object ** 418Message ** 42018 Adaptation and Extension 423Bridge ** 436Object Adapter ** 438Chain of Responsibility * 440Interpreter 442Interceptor ** 444Visitor ** 447Decorator 449Execute-Around Object ** 451Template Method * 453Strategy ** 455Null Object ** 457Wrapper Facade ** 459Declarative Component Configuration * 46119 Modal Behavior 463Objects for States * 467Methods for States * 469Collections for States ** 47120 Resource Management 473Container * 488Component Configurator * 490Object Manager ** 492Lookup ** 495Virtual Proxy ** 497Lifecycle Callback ** 499Task Coordinator * 501Resource Pool ** 503Resource Cache ** 505Lazy Acquisition ** 507Eager Acquisition ** 509Partial Acquisition * 511Activator ** 513Evictor ** 515Leasing ** 517Automated Garbage Collection ** 519Counting Handle ** 522Abstract Factory ** 525Builder * 527Factory Method ** 529Disposal Method ** 53121 Database Access 533Database Access Layer ** 538Data Mapper ** 540Row Data Gateway ** 542Table Data Gateway ** 544Active Record 54622 A Departing Thought 549Glossary 553References 573Index of Patterns 587Index of Names 593Subject Index 595

"The authors' decision to include a real-life use case was a good strategy it illustrate the application of the pattern language." (Computing Reviews, February 15, 2008)

Frank Buschmann, Siemens AG, Germany Kevlin Henney, Curbralan, Bristol, UK Douglas C. Schmidt, Vanderbilt University, Nashville, Tennessee, USA

• Foreword xvAbout This Book xviiAbout The Authors xxiiiGuide To The Reader xxviiPart I Some Concepts 11 On Patterns and Pattern Languages 31.1 Patterns Introduced 41.2 Inside Patterns 61.3 Between Patterns 101.4 Into Pattern Languages 131.5 Patterns Connected 152 On Distributed Systems 172.1 Benefits of Distribution 182.2 Challenges of Distribution 202.3 Technologies for Supporting Distribution 222.4 Limitations of Middleware 323 On the Pattern Language 333.1 Intent, Scope, and Audience 343.2 Origins and Genesis 353.3 Structure and Content 363.4 Presentation 443.5 Practical Use 49Part II A Story 534 Warehouse Management Process Control 574.1 System Scope 584.2 Warehouse Management Process Control 605 Baseline Architecture 655.1 Architecture Context 665.2 Partitioning the Big Ball of Mud 675.3 Decomposing the Layers 685.4 Accessing Domain Object Functionality 715.5 Bridging the Network 725.6 Separating User Interfaces 765.7 Distributing Functionality 795.8 Supporting Concurrent Domain Object Access 825.9 Achieving Scalable Concurrency 855.10 Crossing the Object-Oriented/Relational Divide 875.11 Configuring Domain Objects at Runtime 895.12 Baseline Architecture Summary 906 Communication Middleware 956.1 A Middleware Architecture for Distributed Systems 966.2 Structuring the Internal Design of the Middleware 1006.3 Encapsulating Low-level System Mechanisms 1036.4 Demultiplexing ORB Core Events 1056.5 Managing ORB Connections 1086.6 Enhancing ORB Scalability 1116.7 Implementing a Synchronized Request Queue 1146.8 Interchangeable Internal ORB Mechanisms 1166.9 Consolidating ORB Strategies 1186.10 Dynamic Configuration of ORBs 1216.11 Communication Middleware Summary 1247 Warehouse Topology 1297.1 Warehouse Topology Baseline 1307.2 Representing Hierarchical Storage 1317.3 Navigating the Storage Hierarchy 1337.4 Modeling Storage Properties 1357.5 Varying Storage Behavior 1377.6 Realizing Global Functionality 1407.7 Traversing the Warehouse Topology 1427.8 Supporting Control Flow Extensions 1447.9 Connecting to the Database 1467.10 Maintaining In-Memory Storage Data 1477.11 Configuring the Warehouse Topology 1497.12 Detailing the Explicit Interface 1517.13 Warehouse Topology Summary 1538 The Story Behind The Pattern Story 157Part III The Language 1639 From Mud To Structure 167Domain Model ** 182Layers ** 185Model-View-Controller ** 188Presentation-Abstraction-Control 191Microkernel ** 194Reflection * 197Pipes and Filters ** 200Shared Repository ** 202Blackboard 205Domain Object ** 20810 Distribution Infrastructure 211Messaging ** 221Message Channel ** 224Message Endpoint ** 227Message Translator ** 229Message Router ** 231Publisher-Subscriber ** 234Broker ** 237Client Proxy ** 240Requestor ** 242Invoker ** 244Client Request Handler ** 246Server Request Handler ** 24911 Event Demultiplexing and Dispatching 253Reactor ** 259Proactor * 262Acceptor-Connector ** 265Asynchronous Completion Token ** 26812 Interface Partitioning 271Explicit Interface ** 281Extension Interface ** 284Introspective Interface ** 286Dynamic Invocation Interface * 288Proxy ** 290Business Delegate ** 292Facade ** 294Combined Method ** 296Iterator ** 298Enumeration Method ** 300Batch Method ** 30213 Component Partitioning 305Encapsulated Implementation ** 313Whole-Part ** 317Composite ** 319Master-Slave * 321Half-Object plus Protocol ** 324Replicated Component Group * 32614 Application Control 329Page Controller ** 337Front Controller ** 339Application Controller ** 341Command Processor ** 343Template View ** 345Transform View ** 347Firewall Proxy ** 349Authorization ** 35115 Concurrency 353Half-Sync/Half-Async ** 359Leader/Followers ** 362Active Object ** 365Monitor Object ** 36816 Synchronization 371Guarded Suspension ** 380Future ** 382Thread-Safe Interface * 384Double-Checked Locking 386Strategized Locking ** 388Scoped Locking ** 390Thread-Specific Storage 392Copied Value ** 394Immutable Value ** 39617 Object Interaction 399Observer ** 405Double Dispatch ** 408Mediator * 410Command ** 412Memento ** 414Context Object ** 416Data Transfer Object ** 418Message ** 42018 Adaptation and Extension 423Bridge ** 436Object Adapter ** 438Chain of Responsibility * 440Interpreter 442Interceptor ** 444Visitor ** 447Decorator 449Execute-Around Object ** 451Template Method * 453Strategy ** 455Null Object ** 457Wrapper Facade ** 459Declarative Component Configuration * 46119 Modal Behavior 463Objects for States * 467Methods for States * 469Collections for States ** 47120 Resource Management 473Container * 488Component Configurator * 490Object Manager ** 492Lookup ** 495Virtual Proxy ** 497Lifecycle Callback ** 499Task Coordinator * 501Resource Pool ** 503Resource Cache ** 505Lazy Acquisition ** 507Eager Acquisition ** 509Partial Acquisition * 511Activator ** 513Evictor ** 515Leasing ** 517Automated Garbage Collection ** 519Counting Handle ** 522Abstract Factory ** 525Builder * 527Factory Method ** 529Disposal Method ** 53121 Database Access 533Database Access Layer ** 538Data Mapper ** 540Row Data Gateway ** 542Table Data Gateway ** 544Active Record 54622 A Departing Thought 549Glossary 553References 573Index of Patterns 587Index of Names 593Subject Index 595

"The authors' decision to include a real-life use case was a good strategy it illustrate the application of the pattern language." (Computing Reviews, February 15, 2008)