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:
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:
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.
In PlantUML we can use the special variable %date% to get the current date and time.
The default format shows day of the week, date, time and timezone.
We can change the date format by specifying our format with the Java SimpleDateFromat symbols.
For example to only get the hours and minutes we would write %date[HH:mm]%.
In the following example we use the %date% variable as is and with a custom format:
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:
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:
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:
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
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:
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:
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:
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:
