In a Grails application we can organize our controllers into packages, but if we use the same name for multiple controllers, placed in different packages, then Grails cannot resolve the correct controller name. Grails ignores the package name when finding a controller by name. But with namespace support since Grails 2.3 we can have controllers with the same name, but we can use a namespace property to distinguish between the different controllers.

We can add a new static property to a controller class with the name namespace. The value of this property defines the namespace. We can then write new URL mappings in the grails-app/conf/UrlMappings.groovy file and use the namespace value as a mapping attribute.

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In a previous blog post we learned how we can unit test a template or view independently. But what if we want to unit test a controller that uses the render() method and a template with the template key instead of a view? Normally the view and model are stored in the modelAndView property of the response. We can even use shortcuts in our test code like view and model to check the result. But a render() method invocation with a template key will simply execute the template (also in test code) and the result is put in the response. With the text property of the response we can check the result.

In the following sample controller we use the header template and pass a username model property to render output.

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Grails uses Spring and we can piggyback on the Spring support for resource loading to find for examples files in the classpath of our application. We can use the Spring org.springframework.core.io.Resource or org.springframework.core.io.ResourceLoader interface to find resources in our application.

And since Grails 2.0 we can also use the org.codehaus.groovy.grails.core.io.ResourceLocator interface. In our code we can use the grailsResourceLocator service which implements the ResourceLocator interface. We must inject the grailsResourceLocator service into our code and we use the method findResourceForURI(String) to find a resource. The advantage of the grailsResourceLocator service is that it knows about a Grails application. For example resources in plugins can also be accessed.

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Grails adds a couple of methods and properties to our controller classes automatically. One of the methods is the header() method. With this method we can set a response header with a name and value. The methods accepts two arguments: the first argument is the header name and the second argument is the header value.

In the following controller we invoke the header() method to set the header X-Powered-By with the Grails and Groovy version.

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NOTE: this blog post was written for version 0.8 of the Karma test runner. An updated blog post for the new Karma 0.10 can be found here.

For my current project we are using Maven to build our AngularJS application. Furthermore we use Sonar (recently renamed to SonarCube) to monitor our code standards / best practices and unit test coverage. In this blog post we describe how to integrate the Karma (Testacular) test runner with Maven and how to add your AngularJS (or any JavaScript) application to SonarQube.

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When we want to clone an object there are several ways to do this For instance we can implement Clonable, which makes it possible to duplicate an object. We also can create a new object manually by calling each setter or use a parameterised constructor. In case we want to clone a Hibernate object, there is an extra option available which is more elegant: the Hibernate3BeanReplicator. The Hibernate3BeanReplicator is provided by Beanlib (http://beanlib.sourceforge.net/) and it supports deep clones, so we can also clone related one-to-one objects easily. For example we want to clone the Student object, including all child (one-to-one) objects.

Student student = studentDao.getStudentById(1);

HibernateBeanReplicator replicator = new Hibernate3BeanReplicator();
Student studentCopy = replicator.deepCopy(student);

studentCopy.setId(null);
studentCopy.getRelatedObject().setId(null);

studentDao.save(studentCopy);

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Say you have a arbitrary class under test, which is dependent on a class DataProcessor which has a method with the following signature:

 String processData(String data, MultivaluedMap  params, Token token)

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Gradle already has a powerful DSL, but Gradle wouldn't be Gradle if we couldn't extend the DSL ourselves. Maybe we have our own naming conventions in our company or we have a special problem domain we want to express in a Gradle build script. We can use the ExtensionContainer, available via project.extensions, to add new concepts to our build scripts. In the Standardizing your enterprise build environment webinar by Luke Daley some examples are shown on how to extend the DSL. Also in the samples folder of the Gradle distribution are examples on how to create a custom DSL.

Let's first create a simple DSL extension. We first define a new class CommonDependencies with methods to define dependencies in a Java project. We want to use these methods with descriptive names in our build scripts. To add the class we use the create() method of the ExtensionContainer. The first argument is a name that needs to be unique within the build. The name can be used together with a configuration block in the script to invoke methods on the class we pass as the second argument. Finally we can pass constructor arguments for the class as last arguments of the create() method.

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Groovy 2.1 introduced the @DelegatesTo annotation. With this annotation we can document a method and tell which class is responsible for executing the code we pass into the method. If we use @TypeChecked or @CompileStatic then the static type checker of the compiler will use this information to check at compile-time if the code is correct. And finally this annotation allows an IDE to give extra support like code completion.

Suppose we have the following class Reservation with the method submit(). The method accepts a closure with methods that need to be applied with the instance of the Reservation class. This is a very common pattern for writing simple DSLs in Groovy.

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Apache Wicket is a populair web framework. There are a many reasons why I like to use Wicket, for instance: it offers a great mark-up/logic separation and using Wicket it’s very easy to implement AJAX functionality without writing one line of Javascript.

To provide you with simple and short tips and tricks for Wicket I write this series of blogs. In this first blog of the series I will show you how to create a download link in several ways.

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NOTE: version 7 of WebStorm already comes with built-in Karma support.
However IntelliJ IDEA 12 users will have to wait for v. 13, making this article still relevant for them.

Recently I started using the Karma (previously called Testacular) test runner for JavaScript, as an alternative for the “Jasmine Maven Plugin”. The primary reason for switching is that Karma uses actual browsers (like Chrome, Firefox, Safari and even IE) to execute the tests instead of the emulated Mozilla Rhino JavaScript engine. To increase productivity I wondered if I could also integrate Karma into WebStorm / IDEA. Currently WebStorm doesn't offer out of the box support the Karma test runner. However it does support executing any kind of NodeJS application (like Karma). Installing the NodeJS plugin (only needed when using IDEA Ultimate) When using IntelliJ IDEA Ultimate you first have to manually install the NodeJS plugin. To install this plugin:

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Arthur Arts wrote an blog post about Using ArgumentCaptor for generic collections with Mockito. With the ArgumentCaptor in Mockito the parameters of a method call to a mock are captured and can be verified with assertions. In Spock we can also get a hold on the arguments that are passed to a method call of a mock and we can write assertions to check the parameters for certain conditions. When we create a mock in Spock and invoke a method on the mock the arguments are matched using the equals() implementation of the argument type. If they are not equal Spock will tell us by showing a message that there are too few invocations of the method call. Let’s show this with an example. First we create some classes we want to test:

package com.jdriven.spock

class ClassUnderTest {

    private final Greeting greeting

    ClassUnderTest(final Greeting greeting) {
        this.greeting = greeting
    }

    String greeting(final List<Person> people) {
        greeting.sayHello(people)
    }
}

package com.jdriven.spock

interface Greeting {
    String sayHello(final List<Person> people)
}

package com.jdriven.spock

@groovy.transform.Canonical
class Person {
    String name
}

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