luksrn

Object.metaClass.miau = {-> println "Miau!!!"}

"String".miau()

145.miau()

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public interface GroovyObject {
  Object invokeMethod(String name, Object args);
  Object getProperty(String property);
  void setProperty(String property, Object newValue);
  MetaClass getMetaClass();
  void setMetaClass(MetaClass metaClass);
}

luksrn

class DemoController implements DatabaseExceptionHandler {
  // todos os métodos de manipuação de exceção são definidos
  // em DatabaseExceptionHandler serão adicionados
  // nesta classe em tempo de execução
}

luksrn

package com.demo
trait DatabaseExceptionHandler {
    def handleSQLException(SQLException e) {
           // manipular SQLException
    }
    def handleBatchUpdateException(BatchUpdateException e) {
           // manipular BatchUpdateException
    }
}

luksrn

package demo
class DemoController {
  def someAction() {
         // do some work
  }
  def handleSQLException(SQLException e) {
         render 'A SQLException Was Handled'
  }
  def handleBatchUpdateException(BatchUpdateException e) {
         redirect controller: 'logging', action: 'batchProblem'

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class ComponenteCustomizado implements WebAttributes {
     def meuMetodo() {
       println "params: " + params
     }
}

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trait Controller implements ResponseRenderer, 
                            ResponseRedirector, 
                            RequestForwarder, 
                            DataBinder, 
                            WebAttributes, 
                            ServletAttributes {
//...
}

luksrn

    class C implements A,B {
        String exec() { A.super.exec() }
    }

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trait A {
  String exec() { 'A' }
}
trait B {
  String exec() { 'B' }
}
class C implements A,B {}
def c = new C()
println c.exec()

luksrn

@Grapes(
 @Grab(group='log4j', module='log4j', version='1.2.16')
)
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.Log;
trait Loggable {
  private Log logger
  Log getLog() {
        if( !logger )
                 logger = LogFactory.getLog( this.getClass() )