Groovy

Apache Groovy is a powerful, optionally typed and dynamic language, with static-typing and static compilation capabilities, for the Java platform aimed at improving developer productivity thanks to a concise, familiar and easy to learn syntax

Install

   1 cd  ~/
   2 wget https://groovy.jfrog.io/artifactory/dist-release-local/groovy-zips/apache-groovy-binary-4.0.26.zip 
   3 unzip apache-groovy-binary-4.0.26.zip 
   4 
   5 nano ~/.bashrc
   6 # export GROOVY_HOME=$HOME/groovy-4.0.26
   7 # export PATH=$PATH:$GROOVY_HOME/bin
   8 . ~/.bashrc 
   9 groovysh
  10 # a = 1
  11 # print("aaa $a")
  12 # :q
  13 groovyConsole # opens window that allows to run groovy code
  14

groovyc - compiler

nano MyClass.groovy

   1 class X{
   2   int amount
   3 }
   4 
   5 def x = new X()
   6 x.amount = 1
   7 println("${x.amount}")

   1 groovyc MyClass.groovy # compile
   2 java -cp . -jar $GROOVY_HOME/lib/groovy-4.0.26.jar MyClass # run code
   3 java -jar $GROOVY_HOME/lib/groovy-4.0.26.jar MyClass # run code
   4

swing - groovy

   1 import groovy.swing.SwingBuilder
   2 import java.awt.BorderLayout as BL
   3 
   4 count = 0
   5 
   6 def actionPerformedFn(){
   7   count++; 
   8   textlabel.text = "Clicked ${count} time(s)."
   9   println "clicked"
  10 }
  11 
  12 def quitFn(){
  13   System.exit(0) 
  14 }
  15 
  16 new SwingBuilder().edt {
  17   frame(title: 'Frame', size: [300, 300], show: true) {
  18     borderLayout()
  19     textlabel = label(text: 'Click the button!', constraints: BL.NORTH)
  20     button(text:'Click Me', actionPerformed: {actionPerformedFn()}, constraints:BL.WEST)
  21     button(text:'Quit', actionPerformed: {quitFn()}, constraints:BL.EAST)
  22   }
  23 }

   1 groovy swing.groovy # run with groovy
   2 groovyc swing.groovy  # compile code
   3 # run compiled code with java
   4 java -cp .:$GROOVY_HOME/lib/groovy-4.0.26.jar:$GROOVY_HOME/lib/groovy-swing-4.0.26.jar swing

Map example - map.groovy

   1 /*
   2 run: groovy map.groovy
   3 compile and run with java
   4   groovyc map.groovy 
   5   java -cp .:$GROOVY_HOME/lib/groovy-4.0.26.jar map
   6 */
   7 def map=[:]
   8 map.x = 1
   9 map["y"] = "ab"
  10 print("Serialized map $map \n")
  11 
  12 print("Keys size: ${map.keySet().size()} \n")
  13 for(key in map.keySet()){
  14   print "$key: ${map["$key"]}\n"
  15 }