‘global’ keyword is used to define and access global variables. Example !global $counter = 1 !global $counter = $counter + 1   globalVariables.txt @startuml !global $counter = 1 !function $sum($a, $b) !global $counter = $counter + 1 !return $a + $b !endfunction !function $sub($a, $b) !global $counter = $counter + 1 !return $a - $b !endfunction !$a = 20 !$b = 5 sys1 -> sys2 : $counter. Sum of $a and $b is $sum(20, 5) sys1 -> sys2 : $counter. Sub of $a and $b is $sub(20, 5) !$a = 25 !$b = 15 sys1 -> sys2 : $counter. Sum of $a and $b is $su ..read more

Using the keyword !startsub, !endsub, !includesub, you can specify subparts and include them in a file. Define part !startsub SubPart1 S1 -> S2 : SubPart1 msg1 S1 -> S3 : SubPart1 msg2 S1 -> S4 : SubPart1 msg3 !endsub Use the part !includesub parts.txt!SubPart1   parts.txt @startuml !startsub SubPart1 S1 -> S2 : SubPart1 msg1 S1 -> S3 : SubPart1 msg2 S1 -> S4 : SubPart1 msg3 !endsub !startsub SubPart2 D1 -> D2 : SubPart2 msg1 D1 -> D3 : SubPart3 msg2 D1 -> D4 : SubPart3 msg3 !endsub @e ..read more

‘includeurl’ directive include the ‘plantuml’ data from given url this file includeURL.txt @startuml !define AWSPUML https://raw.githubusercontent.com/milo-minderbinder/AWS-PlantUML/release/18-2-22/dist !includeurl AWSPUML/common.puml !includeurl AWSPUML/Storage/AmazonS3/AmazonS3.puml !includeurl AWSPUML/Storage/AmazonS3/bucket/bucket.puml AMAZONS3(s3_internal) AMAZONS3(s3_partner,"Vendor's S3") s3_internal <-- s3_partner @enduml   Above snippet generate below diagram.      Previous               ..read more

  What is a data center? Data centers are gaint buildings that hosts tens of thousands of interconnected servers and an array of cooling systems. Due to security concerns, access to these facilities is typically restricted to very few employees.   Core components of Data center 1. Network Infrastructure The network infrastructure acts as the central nervous system of the data center, connecting various components such as physical and virtual servers, storage units, data center services, and external connections to reach end-user destinations.   2. Storage Infrastructure Storage ..read more

!include directive We can include files in our program using !include directive. This feature is helpful in reusing the components in many diagrams.   For example, let’s define list.txt file.   list.txt interface Collection{ } interface Iterable { Iterator iterator() } interface List{ int size() void clear() boolean add(E e) void add(int index, E element) addAll(Collection<? extends E> c) void clear() boolean contains(Object o) } Collection <|-- List Iterable <|-- List   Let’s use the conte ..read more

Functions, procedures can also be called using keyword arguments, i.e, by using argument names. Example !function $sum($a, $b) !global $counter = $counter + 1 !return $a + $b !endfunction   Above function can be called in following ways. $sum($b=45, $a=5) $sum($b=45, 5) $sum(5, 45) keywordArguments.txt @startuml !global $counter = 1 !function $sum($a, $b) !global $counter = $counter + 1 !return $a + $b !endfunction sys1 -> sys2 : $counter. sum of 5 and 45 is $sum($b=45, $a=5) sys1 -> sys2 : $counter. sum of 5 and 45 is $sum($b=45, 5) sys1 -> ..read more

You can assign default values to function or procedure parameters. !function $sum($a=5, $b=6) !global $counter = $counter + 1 !return $a + $b !endfunction $sum() : Since I do not pass any arguments, a =5, b=6 are used here $sum(20): a= 20, b=6 $sum(20, 30): a=20, b=30  defaultValues.txt   @startuml !global $counter = 1 !function $sum($a=5, $b=6) !global $counter = $counter + 1 !return $a + $b !endfunction sys1 -> sys2 : $counter. sum() is $sum() sys1 -> sys2 : $counter. sum(20) is $sum(20) sys1 -> sys2 : $counter. sum(20, 30) is $sum(20 ..read more

A function name should starts with $ and all the argument names should start with $.   Unlike procedures, a function can return a value.   A function can be called from other function and can be called from other procedure.   functions.txt @startuml !function $sum($a, $b) !return $a + $b !endfunction !function $sub($a, $b) !return $a - $b !endfunction !$a = 20 !$b = 5 sys1 -> sys2 : Sum of $a and $b is $sum(20, 5) sys1 -> sys2 : Sub of $a and $b is $sub(20, 5) @enduml Above snippet generate below diagram.   If a function has one liner body ..read more

PlantUML support procedures, where you can define once and reuse.   a.   Procedure names should start with a $ b.   Argument names should start with a $ c.    Procedures can call other procedures   procedures.txt @startuml !procedure $fib($arg) !$a = 0 !$b = 1 !$counter = 0 !$fib = 0 !while $counter < $arg #DarkSalmon:for the iteration $counter; #palegreen:a=$a, b=$b; !$fib = $a + $b !$a = $b !$b = $fib #pa ..read more

!while, !endwhile keywords are used to define loops. loops.txt @startuml !procedure $fib($arg) !$a = 0 !$b = 1 !$counter = 0 !$fib = 0 !while $counter < $arg #DarkSalmon:for the iteration $counter; #palegreen:a=$a, b=$b; !$fib = $a + $b !$a = $b !$b = $fib #palegreen:fib=$fib; !$counter = $counter + 1 !endwhile !endprocedure start $fib(5) end @enduml Above snippet shows what is happening in each iteration of fibo ..read more