Groovy Programming Examples

Monitoring the JVM

groovy

import java.lang.management.*

def os = ManagementFactory.operatingSystemMXBean 
println """OPERATING SYSTEM: 
\tOS architecture = $os.arch 
\tOS name = $os.name 
\tOS version = $os.version 
\tOS processors = $os.availableProcessors 
""" 
 
def rt = ManagementFactory.runtimeMXBean 
println """RUNTIME: 
   \tRuntime name = $rt.name 
   \tRuntime spec name = $rt.specName 
   \tRuntime vendor = $rt.specVendor 
   \tRuntime spec version = $rt.specVersion 
   \tRuntime management spec version = $rt.managementSpecVersion 
   """ 

def mem = ManagementFactory.memoryMXBean 
def heapUsage = mem.heapMemoryUsage 
def nonHeapUsage = mem.nonHeapMemoryUsage 

println """MEMORY: 
   HEAP STORAGE: 
      \tMemory committed = $heapUsage.committed 
      \tMemory init = $heapUsage.init 
      \tMemory max = $heapUsage.max 
      \tMemory used = $heapUsage.used NON-HEAP STORAGE: 
      \tNon-heap memory committed = $nonHeapUsage.committed 
      \tNon-heap memory init = $nonHeapUsage.init 
      \tNon-heap memory max = $nonHeapUsage.max 
      \tNon-heap memory used = $nonHeapUsage.used 
   """
  
println "GARBAGE COLLECTION:" 
ManagementFactory.garbageCollectorMXBeans.each { gc ->
   println "\tname = $gc.name"
   println "\t\tcollection count = $gc.collectionCount"
   println "\t\tcollection time = $gc.collectionTime"
   String[] mpoolNames =   gc.memoryPoolNames
	
   mpoolNames.each { 
      mpoolName -> println "\t\tmpool name = $mpoolName"
   } 
}

JsonOutput

groovy

import groovy.json.JsonOutput  
class Example {
   static void main(String[] args) {
      def output = JsonOutput.toJson([ new Student(name: 'John',ID:1),
         new Student(name: 'Mark',ID:2)])
      println(output);  
   } 
}
 
class Student {
   String name
   int ID; 
}

Monitoring the JVM

groovy

import java.lang.management.*

def os = ManagementFactory.operatingSystemMXBean 
println """OPERATING SYSTEM: 
\tOS architecture = $os.arch 
\tOS name = $os.name 
\tOS version = $os.version 
\tOS processors = $os.availableProcessors 
""" 
 
def rt = ManagementFactory.runtimeMXBean 
println """RUNTIME: 
   \tRuntime name = $rt.name 
   \tRuntime spec name = $rt.specName 
   \tRuntime vendor = $rt.specVendor 
   \tRuntime spec version = $rt.specVersion 
   \tRuntime management spec version = $rt.managementSpecVersion 
   """ 

def mem = ManagementFactory.memoryMXBean 
def heapUsage = mem.heapMemoryUsage 
def nonHeapUsage = mem.nonHeapMemoryUsage 

println """MEMORY: 
   HEAP STORAGE: 
      \tMemory committed = $heapUsage.committed 
      \tMemory init = $heapUsage.init 
      \tMemory max = $heapUsage.max 
      \tMemory used = $heapUsage.used NON-HEAP STORAGE: 
      \tNon-heap memory committed = $nonHeapUsage.committed 
      \tNon-heap memory init = $nonHeapUsage.init 
      \tNon-heap memory max = $nonHeapUsage.max 
      \tNon-heap memory used = $nonHeapUsage.used 
   """
  
println "GARBAGE COLLECTION:" 
ManagementFactory.garbageCollectorMXBeans.each { gc ->
   println "\tname = $gc.name"
   println "\t\tcollection count = $gc.collectionCount"
   println "\t\tcollection time = $gc.collectionTime"
   String[] mpoolNames =   gc.memoryPoolNames
	
   mpoolNames.each { 
      mpoolName -> println "\t\tmpool name = $mpoolName"
   } 
}

entire XML document

groovy

import groovy.xml.MarkupBuilder 

class Example {
   static void main(String[] args) {
      def mp = [1 : ['Enemy Behind', 'War, Thriller','DVD','2003', 
         'PG', '10','Talk about a US-Japan war'],
         2 : ['Transformers','Anime, Science Fiction','DVD','1989', 
         'R', '8','A scientific fiction'],
         3 : ['Trigun','Anime, Action','DVD','1986', 
         'PG', '10','Vash the Stam pede'],
         4 : ['Ishtar','Comedy','VHS','1987', 'PG', 
         '2','Viewable boredom ']] 
			
      def mB = new MarkupBuilder()  
		
      // Compose the builder
      def MOVIEDB = mB.collection('shelf': 'New Arrivals') {
         mp.each {
            sd -> 
            mB.movie('title': sd.value[0]) {  
               type(sd.value[1])
               format(sd.value[2])
               year(sd.value[3]) 
               rating(sd.value[4])
               stars(sd.value[4]) 
               description(sd.value[5]) 
            }
         }
      }
   } 
}

XML Markup Builder

groovy

import groovy.xml.MarkupBuilder 

class Example {
   static void main(String[] args) {
      def mB = new MarkupBuilder()
		
      // Compose the builder
      mB.collection(shelf : 'New Arrivals') {
         movie(title : 'Enemy Behind')
         type('War, Thriller')
         format('DVD')
         year('2003')
         rating('PG')
         stars(10)
         description('Talk about a US-Japan war') 
      }
   } 
}

Groovy collect()

groovy

class Example {
   static void main(String[] args) {
      def lst = [1,2,3,4];
      def newlst = [];
      newlst = lst.collect {element -> return element * element}
      println(newlst);
   } 
}

Groovy every()

groovy

class Example {
   static void main(String[] args) {
      def lst = [1,2,3,4];
      def value;
		
      // Are all value above 2
      value = lst.every{element -> element > 2}
      println(value);
		
      // Are all value above 4 
      value = lst.every{element -> element > 4}
      println(value);  
      def largelst = [4,5,6];
		
      // Are all value above 2
      value = largelst.every{element -> element > 2}
      println(value);
   } 
}

Groovy any()

groovy

class Example {
   static void main(String[] args) {
      def lst = [1,2,3,4];
      def value;
		
      // Is there any value above 2
      value = lst.any{element -> element > 2}
      println(value);
		
      // Is there any value above 4
      value = lst.any{element -> element > 4}
      println(value); 
   } 
}

Groovy findAll()

groovy

class Example {
   static void main(String[] args) {
      def lst = [1,2,3,4];
      def value;
		
      value = lst.findAll{element -> element > 2}
      value.each {println it}
   } 
}

Groovy find()

groovy

class Example {
   static void main(String[] args) {
      def lst = [1,2,3,4];
      def value;
		
      value = lst.find {element -> element > 2}
      println(value);
   } 
}

Follow

Newsletter