About mrhaki

My name is Hubert A. Klein Ikkink also known as mrhaki. I work at the great IT company JDriven. Here I work on projects with Groovy & Grails, Gradle and Spring. At JDriven we focus on SpringSource technologies. All colleagues want to learn new technologies, support craftmanship and are very eager to learn. This is truly a great environment to work in. You can contact me via Google+ or @mrhaki.

Awesome Asciidoctor: Using Filename Starting With Dot As Block Title

Adding a block title in Asciidoctor is easily done by adding a line at the top of the block that starts with a dot (.). The text following the dot is then used as the title of the block. But if the text of the title itself starts with a dot (.) Asciidoctor get’s confused. For example if we want to use a filename that starts with a dot (.filename) we must use different syntax to set the block title with the filename.

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Gradle Goodness: Run Task Ignoring Up-to-date Checks

Gradle builds are fast because Gradle supports incremental tasks. This means Gradle can determine if input or output of task has changed, before running the task. If nothing has changed a task is marked a up-to-date and the task is not executed, otherwise the task is executed. If we want execute a task even if it is up-to-date we must use the command line option --rerun-tasks.

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Spring Sweets: Add (Extra) Build Information To Info Endpoint

With Spring Boot Actuator we get some useful endpoints in our application to check on our application when it is running. One of the endpoints is the /info endpoint. We can add information about our application if Spring Boot finds a file META-INF/build-info.properties in the classpath of our application. With the Gradle Spring Boot plugin we can generate the build-info.properties file. When we apply the Gradle Spring Boot plugin to our project we get a Gradle extension springBoot in our build file. With this extension we can configure Spring Boot for our project. To generate project information that is used by the /info endpoint we must add the method statement buildInfo() inside the springBoot extension. With this method statement the Gradle Spring Boot plugin generates a file build/main/resources/META-INF/build-info.properties..

Let’s run our application and send a request for /info:

To override the default properties or to add new properties we must provide a configuration closure to the buildInfo method. If we a built-in key as the name of the property it is overridden with a new value, otherwise the key is added as a new property. In the following example we add some extra properties and override the properties time and name:

We restart the application and invoke the /info endpoint to get more results for the build:

Written with Spring Boot 1.4.2.RELEASE.

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Spring Sweets: Add Git Info To Info Endpoint

With Spring Boot Actuator we get some endpoints that display information about our application. One of the endpoints is the /info endpoint. If our project uses Git we can add information about Git to the /info endpoint. By default Spring Boot will look for a file git.properties in the classpath of our application. The file is a Java properties file with keys that start with git. and have values like the branch name, commit identifier and commit message. Spring Boot uses this information and when we request the /info endpoint we get a response with the information. This can be very useful to check the Git information that was used to build the application. To create the git.properties file we can use a Gradle (or Maven) plugin that will do the work for us.

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PlantUML Pleasantness: Get PlantUML Definition From PNG

When we generate a PNG version of our PlantUML definition the original definition is stored in the PNG image. We can extract the definition using the command line option -metadata. We need to provide the PNG file and in the output we see the original PlantUML definition.

The following PNG image (activity.png) is created with PlantUML:

Next we run PlantUML from the command line using the option -metadata:

At the top we see the section @startuml..@enduml with the PlantUML syntax that was used to generate the PNG image.

Written with PlantUML 8051.

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PlantUML Pleasantness: Change Line Style And Color

We can change the line style and color when we “draw” the line in our PlantUML definition. We must set the line style and color between square brackets ([]). We can choose the following line styles: bold, plain, dotted and dashed. The color is either a color name or a hexadecimal RGB code prefixed with a hash (#).

In the following example activity diagram we apply different styles and colors to the lines:

When we generate the activity diagram we see the different line styles and colors:

Written with PlantUML 8051.

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Gradle Goodness: Passing Environment Variable Via Delegate Run Action In IntelliJ IDEA

IntelliJ IDEA 2016.3 introduced the option to delegate the run action to Gradle. This means when we have a run Configuration for our Java or Groovy classes we can use the Run action and IDEA will use Gradle to run the application. Actually IntelliJ IDEA creates a new task of type JavaExec dynamically for our specific run configuration with the main property set to the class we want to run.

In the Edit Configuration dialog window we can set the command line argument and Java system properties. These are passed on to the dynamically created JavaExec task and are accessible from within the class that runs. The environment variables that can be set in the Edit Configuration dialog windows are not passed to the JavaExec task configuration. But we can do it ourselves in the build script file of our project. We look for the dynamically created task and use the environment method to add a environment variable that can be access in the Java or Groovy class that is executed.

We start our example with a simple Groovy class that can be executed using JavaExec. We simply print out the given input arguments, all Java system properties that start with sampleApp and finally all environment variables that start with SAMPLE_APP:

We create a new Run/Debug Configuration for our SampleApp class:

When we click on OK to save the configuration we are ready to use the Run ‘SampleApp’ action. When we look at the output we get the following result:

Notice the Gradle tasks that are invoked and the dynamically created run SampleApp task. We see our Java system property is passed on, together with the program arguments. The environment variable is not passed on. We must add some extra configuration to the dynamically created task run Sample in our build.gradle file:

Now we re-run our application and we get the following output:

Written with IntelliJ IDEA 2016.3 and Gradle 3.2.1.

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Awesome Asciidoctor: Change Number Style For Ordered Lists

To write a (nested) ordered lists in Asciidoctor is easy. We need to start the line with a dot (.) followed by a space and the list item text. The number of dots reflects the levels of nesting. So with two dots (..) we have a nested list item. By default each nested level has a separate numbering style. The first level has arabic numbering, the second lower case alphanumeric, the third upper case alphanumeric, the fourth lower case roman and the fifth (which is maximum depth of nested levels in Asciidoctor) has style upper case roman. But we can change this by setting a block style for each nested level block. The name of the block style is arabic, loweralpha, upperalpha, lowerromann or upperroman. With the HTML5 backend we can also use decimal and lowergreek.

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Grails Goodness: Writing Log Messages With Grails 3.2 (Slf4J)

Grails 3.2 changed the logging implementation for the log field that is automatically injected in the Grails artefacts, like controllers and services. Before Grails 3.2 the log field was from Jakarta Apache Commons Log class, but since Grails 3.2 this has become the Logger class from Slf4J API. A big difference is the fact that the methods for logging on the Logger class don’t accepts an Object as the first argument. Before there would be an implicit toString invocation on an object, but that doesn’t work anymore.

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