OSGi in Action. RICHARD S. HALL KARL PAULS STUART McCULLOCH DAVID SAVAGE CREATING MODULAR APPLICATIONS IN JAVA MANNING. Greenwich (74 w. long.

Transcription

1 OSGi in Action CREATING MODULAR APPLICATIONS IN JAVA RICHARD S. HALL KARL PAULS STUART McCULLOCH DAVID SAVAGE 11 MANNING Greenwich (74 w. long.)

2 contents foreword xiv preface xvii acknowledgments xix about this book xx about the authors xxv PART 1 INTRODUCING OSGI: MODULARITY, LIFECYCLE, AND SERVICES OSGi revealed The what and why of OSGi 4 Java's modularity limitations 5 Can OSGi help you? An architectural overview of OSGi 9 The OSGi framework 9 Putting it all together "Hello, world!" examples 12 Module layer example 12 Lifecycle layer example 14 Service layer example 16 Setting the stage 18

3 1.4 Putting OSGi in context 19 Java Enterprise Edition 19 Jini 20' NetBeans 20 Java Management Extensions 20 Lightweight containers 21 Java Business Integration 21 JSR JSR Service Component Architecture 22.NET Summary 23 Mastering modularity What is modularity? 25 Modularity vs. object orientation Why modularize? Modularizing a simple paint program Introducing bundles 31 The bundle's role in physical modularity 32 The bundle's role in logical modularity Defining bundles with metadata 34 Human-readable information 35 Bundle identification 36 Code visibility 39 Class-search order Finalizing the paint program design 50 Improving the paint program's modularization 51 Launching the new paint program OSGi dependency resolution 53 Resolving dependencies automatically 53 Ensuring consistency with uses constraints Reviewing the benefits of the modular paint program Summary 68 Learning lifecycle Introducing lifecycle management 70 What is lifecycle management? 70 Why lifecycle management? OSGi bundle lifecycle 72 Introducing lifecycle to the paint program 73 The OSGi framework's role in the lifecycle 75 The bundle activator manifest entry 76 Introducing the lifecycle API 77 Lifecycle state diagram 83 Bundle cache and framework restarts Using the lifecycle API in your bundles 85 Configuring bundles 86 Deploying bundles 88 Inspecting framework state 92 Persisting bundle state 93 Listening for events 96 Bundle suicide 99

4 3.4 Dynamically extending the paint program Lifecycle and modularity 108 Resolving bundles 108 Refreshing bundles 110 When updating isn 't updated Summary 115 A Studying services 117 * 4.1 The what, why, and when of services 118 What is a service? 118- Why use services? 119 When to use services 123 When not to use services 124 Still not sure? OSGi services in action 125 Publishing a service 126 Finding and binding services Dealing with dynamics 132 Avoiding common pitfalls 133 Listening for services 136 Tracking services Using services in the paint example 143 Defining a shape service 144 Publishing a shape service 144 Tracking shape services Relating services to modularity and lifecycle 146 Why can't I see my service? 147 Can I provide a bundle-specific service? 147' When should 1unget a service? 148 When should I unregister my service? 148 Should I bundle interfaces separately? Delving 4.6 Standard services 149 Core services 150 Compendium services Summary 152 deeper into modularity Managing your exports 155 Importing your exports 155 Implicit export attributes 158 Mandatory export attributes 160 Export filtering 161 Duplicate exports Loosening your imports 164 Optional imports 164 Dynamic imports 165 Optional vs. dynamic imports 166 Logging example Requiring bundles 171 Declaring bundle dependencies 171 Aggregating split packages 173 Issues with bundle dependencies 176

5 5.4 Dividing bundles into fragments 177 Understanding fragments 177 Using fragments for localization Dealing with your environment 183 Requiring execution environments 184 Bundling native libraries Summary 187 PART 2 OSGi IN PRACTICE., Moving toward bundles TurningJARs into bundles 192 Choosing an identity 192 Exporting packages 195 Discovering what to import 199 Embedding vs. importing 203 Adding lifecycle support 204 JAR file to bundle cheat sheet Splitting an application into bundles 206 Making a mega bundle 206 Slicing code into bundles 216 Loosening things up 221 To bundle or not to bundle? Summary 229 Testing applications Migrating tests to OSGi 231 In-container testing 231 Bundling tests 232 Covering all the bases Mocking OSGi 237 Testing expected behavior 237 Mocking in action 238 Mocking unexpected situations 240 Coping with multithreaded tests 241 Exposing race conditions Advanced OSGi testing 244 OSGi test tools 245 Running tests on multiple frameworks 246 Unit testing 250 Integration testing 251 Management testing Summary 257 Debugging applications Debugging bundles 259 Debugging in action 261 Making things right with HotSwap 266

6 8.2 Solving class-loading issues 271 ClassNotFoundException vs. NoClassDefFoundError 272 Casting problems 274- Using uses constraints 275' Staying clear of Class.forName() 278 Following the Thread Context Class Loader Tracking down memory leaks 283 Analyzing OSGi heap dumps Dangling services 287 Finding a dangling service 287 Protecting against dangling services Summary 290 Managing bundles Versioning packages and bundles 293 Meaningful versioning 293 Package versioning 295 Bundle versioning Configuring bundles 299 Configuration Admin Service 299 Metaiype Service 309 Preferences Service Starting bundles lazily 314 Understanding activation policies 315 Using activation policies Summary 317 ~f/i Managing applications 319 JL\J 10.1 Deploying bundles 320 Introducing management agents 320 OSGi Bundle Repository 321 Deployment Admin Ordering bundle activation 337 Introducing the Start Level Service 338 Using the Start Level Service Summary 342 PART 3 ADVANCED TOPICS 343 Component models and frameworks Understanding component orientation 346 What are components? 346 Why do we want components? 348

7 11.2 OSGi and components 349 OSGi's service-oriented component model 349 Improving upon OSGi's component model 351 Painting with components Declarative Services 355 Building Declarative Services components 356 Providing services with Declarative Services 357 Consuming services with Declarative Services 359 Declarative Services component lifecycle Summary 371 Advanced component frameworks Blueprint Container 374 Blueprint architecture 374 Providing services with Blueprint 375 Consuming services with Blueprint 378 Blueprint component lifecycle 382 Advanced Blueprint features Apache Felix ipojo 391 Building ipojo components 392 Providing services with ipojo 393 Consuming services with ipojo 395 ipojo component lifecycle 400 Instantiating components with ipojo Mix and match Summary 411 Launching and embedding an OSGi framework Standard launching and embedding 413 Framework API overview 413 Creating a framework instance 415 Configuring a framework 417 Starting a framework instance 419 Stopping a framework instance Launching the framework 421 Determining which bundles to install 422 Shutting down cleanly 422 Configuring, creating, and starting the framework 423 Installing the bundles 424 Starting the bundles 424 Starting the main bundle 425 Waiting for shutdown Embedding the framework 427 Inside vs. outside 427 Who's in control? 431 Embedded framework example Summary 437 Securing your applications To secure or not to secure 439

8 14.2 Security:justdoit 440 Java and OSGi security OSGi-specific permissions 444 PackagePermission 444 BundlePermission 445 Admin- Permission 446 ServicePermission 447 Relative file permissions Managing permissions with Conditional Permission Admin 449 Conditional permissions 449 Introducing the Conditional Permission Admin Service 450 Bundle location condition 451 Using ConditionalPermissionAdmin 452 Implementing a policy-file reader Digitally signed bundles 457 Learning the terminology 458 Creating certificates and signing bundles 458 BundleSignerCondition Local permissions Advanced permission management 465 Custom conditions overview 465 Date-based condition 466 User-input condition Bringing it all back home Summary 475 Web applications and web services Creating web applications 478 Using the HTTP Service specification 479 Using the Web Applications specification 488 Standard WARs: the Web URL Handler Providing and consuming web services 493 Providing a web service 494 Consuming a web service 499 Distributing services Summary 510 appendix A Building bundles 513 appendix B OSGi standard services 528 index 531