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.
In the following example we try to use an object as the first argument of the debug method in a controller class:
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With the command line option -checkversion we can see if we have the latest PlantUML version.
The command prints to the console our current PlantUML version and latest version that is available.
Inside a PlantUML definition we can use the command checkversion and generate for example a PNG image with information about our PlantUML version and the latest version that can be downloaded.
First we use the command line option -checkversion for an out-of-date version:
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If we want to know which version of PlantUML we are using we can use the command line option -version.
PlantUML will print the version and also some extra information like the machine name, memory and more.
But we can also create a PlantUML definition with the command version and we can transform it to a graphical presentation like a PNG image.
This can be handy if we use PlantUML in an environment like Asciidoctor with diagram support and we want to know which version of PlantUML is used.
In our first example we run PlantUML from the command line and use the -version option:
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PlantUML has a fun command to create a Sudoku puzzle.
We must use sudoku in our PlantUML definition and a random puzzle is generated.
We can even give a seed value for a given Sudoku so it is generated again.
In the following example PlantUML definition we use the sudoku command:
@startuml
sudoku
@enduml
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With PlantUML we can include external files in our definition with the !include directive.
We specify the file name and the content is included in our PlantUML definition.
The included file can also have multiple @startuml ... @enduml sections and we can refer to individual sections with the !include directive.
We must append to the include file name an exclamation mark (!) followed by either a number or identifier.
If we use a number we specify which section we want to include, where section are numbered starting from 0.
So to get the second section from a file commons.puml we would write !include commons.puml!1.
Alternatively we can use identifiers in the include file.
We append to @startuml an identifier as (id=idValue).
Then from the definition that is including the file we refer to the identifier after an exclamation mark (!).
If our included file commons.puml has a section with id user then we would include it as !include commons.puml!user.
In the following example PlantUML definition we define the file to be included.
We have two sections with @startuml ... @enduml which both have an identifier:
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To change the styling of our generated diagrams with PlantUML we can use the skinparam command. We can set for example font size, style, color, background colors and much more. We can change the style for a specific element or for the whole diagram. We can even set specific styling options for stereotypes. The settings for the stereotype are then applied to all elements in our diagram with that stereotype. We must append <<stereotype name>> to the skin parameter name.
In the following example PlantUML description we apply custom background colors to each stereotype:
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When we write a PlantUML definition the generated graphical diagram is laid out by PlantUML.
In a previous post we learned how to move elements using the length of the connection.
But we can also use a together block with all elements that should be at the same level.
PlantUML will try to keep the elements together when the diagram is drawn.
In the following sample PlantUML definition we want the PostgresDB and Mail elements to be at the same level, so we group them using a together block:
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My colleague, Erik Timmers, and I often have discussions about programming and related technologies.
This blog post is the result of one of those discussions.
We discovered that the function Promise.race didn’t exactly do what we expected.
So we tested it, figured out how it worked, found out what we thought was wrong, and finally created a version of the Promise.race function that does what we expected.
After that we went a little bit further…and added some functionality to the function.
Please note that this code shouldn’t be used in production, or at the very least, it should be tested a bit more.
We did it “because we could”, but also because we wanted to understand the functionality.
If you would like to view, extend, learn from the actual code, the source code is also available on GitHub.
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By default elements in a PlantUML generated diagram have shadows.
To disable shadows we must set the skin parameter shadowing to the value false.
PlantUML will then not create shadows on elements.
In the following sample PlantUML definition we use the value false for the skin parameter shadowing:
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The default colors of PlantUML use red and yellow to draw the diagram elements.
If we want our diagram to be in black, grey and white we can simply set skin parameter monochrome to true.
The generated graphical diagram will now have black, grey and white colors.
In the following sample PlantUML definition we set the diagram skin parameter monochrone to true:
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