Industrial Strength
Groovy
Tools for the Professional
Groovy Developer
Dr Paul King
ASERT
Brisbane, Australia
Draft Only – Updated Version will be on gr8conf site and/or SlideShare

Topics
 Testing: JUnit, TestNG, EasyB, Spock, Instinct
 Mocking: MockFor, GMock, Spock, EasyMock
 Injection: Spring, Guice
 Coverage: Cobertura
 Code style: CodeNarc, IntelliJ
 Duplication: Simian
 Documentation: GroovyDoc
 Builds: Maven, Ant, Gant, Graven, Gradle, Hudson
 Modularisation: Grapes, OSGi

Groovy’s Appeal
 Innovators/Thought leaders
 Ideas, power, flexibility, novelty, thinking community
 Early adopters
 Productivity benefits and collegiate community
 Leverage JVM and potential for mainstream
 Mainstream
 Leverage existing Java skills, low learning curve
 Leverage JVM and production infrastructure
 Professional community
 Tools, tools, tools

Testing: JUnit, TestNG, EasyB,
Spock, Instinct

Mocking: MockFor, GMock, Spock,
EasyMock

Dependency Injection
 Hollywood Principle
 Don’t call us, we’ll call you
 “All problems in computer science can
be solved by another level of indirection”
 "...except for the problem of too many
layers of indirection“
 For attributions, see
http://en.wikipedia.org/wiki/Inversion_of_control

Dependency Injection
 Pattern for loosely coupled & testable objects
class Client { class Client {
Calculator calc = Calculator calc
new CalculatorImpl() def executeCalc(a, b) {
def executeCalc(a, b) { calc.add(a, b)
calc.add(a, b) }
} }
}
 Need to select setter,
 Service locator/factory constructor, field style
 Tightly coupled?  Can add complexity
 Hard to test?  Manage configuration
 Easy to understand?  Direct or framework
 Refactoring/navigation?  Consistency/lifecycle

Dependency Injection: Guice
import com.google.inject.*
@ImplementedBy(CalculatorImpl)
interface Calculator {
def add(a, b)
}
@Singleton
class CalculatorImpl implements Calculator {
private total = 0
def add(a, b) { total++; a + b }
def getTotalCalculations() { 'Total Calculations: ' + total }
String toString() { 'Calc: ' + hashCode()}
}
class Client {
@Inject Calculator calc
// ...
}
def injector = Guice.createInjector()
// ...

Dependency Injection:
Metaprogramming Style
class Calculator {
def total = 0
def add(a, b) { total++; a + b }
}
def INSTANCE = new Calculator()
Calculator.metaClass.constructor = { -> INSTANCE }
def c1 = new Calculator()
def c2 = new Calculator()
assert c1.add(1, 2) == 3
assert c2.add(3, 4) == 7
assert c1.is(c2)
assert [c1, c2].total == [2, 2]

Coverage: Cobertura

Code style: CodeNarc, IntelliJ

Duplication: Simian
Similarity Analyser 2.2.23 -
http://www.redhillconsulting.com.au/products/simian/index.html
Copyright (c) 2003-08 RedHill Consulting Pty. Ltd. All rights reserved.
Simian is not free unless used solely for non-commercial or evaluation
purposes.
{failOnDuplication=true, ignoreCharacterCase=true, ignoreCurlyBraces=true,
ignoreIdentifierCase=true, ignoreModifiers=true, ignoreStringCase=true,
threshold=6}
Found 6 duplicate lines in the following files:
Between lines 201 and 207 in
/Users/haruki_zaemon/Projects/redhill/simian/build/dist/src/java/awt/image/W
ritableRaster.java
...
Found 66375 duplicate lines in 5949 blocks in 1260 files
Processed a total of 390309 significant (1196065 raw) lines in 4242 files
Processing time: 9.490sec

Documentation: GroovyDoc

Builds: Maven, Ant, Gant, Graven,
Gradle, Hudson

Modularisation: Grapes, OSGi