Programming Grails - Cdn.oreilly.com

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Monitoring and the Cloud Foundry UI Plugin 271 Heroku 275 Database Applications 275 Scaling 280 Build Packs 281 Other Providers 282 Other Uses for Cloud Services 282 11. AOP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 Grails Filters 284 HTTP Filters 286 Groovy AOP 287 Registering Metaclass Interceptors 290 Error Code URL Mappings 291 Spring AOP 291 Enabling Spring AOP 293 Defining AspectJ-Annotated Aspects 294 Compile-Time Weaving 297 12. Upgrading Applications and Plugins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 Why Doesn’t the Upgrade Script Do More? 308 A General Approach to Upgrading 310 Upgrading Petclinic: A Case Study 311 A Short History of Grails 320 Grails 1.2 320 Grails 1.2.2 321 Grails 1.2.4 321 Grails 1.3 322 Grails 1.3.1 323 Grails 1.3.2 323 Grails 1.3.4 323 Grails 1.3.6 324 Grails 1.3.7 324 Grails 1.3.8 324 Grails 1.3.9 324 Grails 2.0 325 Grails 2.0.2 331 Grails 2.1.x 331 Grails 2.2.x 331 Notes on Upgrading 331 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 Table of Contents | ix
CHAPTER 1 Introduction to Groovy We can’t talk much about Grails without a solid understanding of Groovy, because it’s so integral to how Grails works. Groovy is a JVM language with a primary goal of extending Java. By adding a Meta Object Protocol (MOP) to enable metaprogramming, Groovy adds powerful capabili‐ ties that enable dynamic programming (changing and adding behavior at runtime), domain-specific languages (DSLs), and a huge number of convenience methods and approaches that simplify your code and make it more powerful. Groovy compiles to bytecode just like Java does (although it creates different bytecode). As Java developers, we tend to think that only javac can compile source code to cre‐ ate .class files, but there are many JVM languages that do as well (including Groovy, JRuby, Jython, and hundreds more). There are also libraries such as BCEL that you can use to programmatically create bytecode. As a result, Groovy and Java interoperate well; you can call Java methods from Groovy and vice versa, a Java class can extend a Groovy class or implement a Groovy interface, and in general, you don’t need to even think about interoperability because it “just works.” The Groovy equivalent of javac is groovyc, and because it compiles both Groovy and Java code, it’s simple to use for your project code. Of course in Grails applications, we rarely even think about this process (except when it fails) because Grails scripts handle that, but if you’re manually compiling code (e.g., in a Gradle build or with Gant), it’s about as simple as working with Java code. Installing Groovy Ordinarily, Grails developers don’t install a Groovy distribution, because each version of Grails ships with the groovy-all JAR with which it was developed. Groovy is a fundamental part of Grails, so using it in a Grails application is trivial. But it’s easy to install if you want to use Groovy outside of Grails, for example, for scripting or to run 1
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Page 4 and 5: Table of Contents Preface. . . . .
Page 6 and 7: Data Validation 69 Custom Validatio
Page 8 and 9: Custom Configurations 148 Mapping V
Page 12 and 13: standalone utility applications. Ju
Page 14 and 15: Collections and Maps Creating and p
Page 16 and 17: The default scope for classes, fiel
Page 18 and 19: Decompiling with JD-GUI I highly re
Page 20 and 21: println hello.getClass().superclass
Page 22 and 23: } }; This can be invoked from Groov
Page 24 and 25: You’ve already seen how property
Page 26 and 27: with: String s = someMethod(...) if
Page 28 and 29: or you could just skip the whole fo
Page 30 and 31: Using a StringBuilder (the preferre
Page 32 and 33: Every Groovy class implements the g
Page 34 and 35: You called add with args [2, 3] nul
Page 36 and 37: The output from the above code is:
Page 38 and 39: assert [alJones, jedSmith, zakJones
Page 40 and 41: } def leftShift(Person child) { chi
Page 42 and 43: def strings = [] but when the right
Page 44 and 45: See the Groovy 2.0 release notes an

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