Interface IManagedProgramInstance

All Superinterfaces:
IProgramInstance
public interface IManagedProgramInstance extends IProgramInstance
The intention for this interface is to provide a lifecycle API for a user-defined base class of a program. The use-case is as follows: 
MyProgram.gsp
-------------

extends MyBase

doSomething()


MyBase.gs
---------

package abc

class MyBase implements IManagedProgramInstance {
  override function beforeExecution() : boolean {
    // determine if the program should execute
  }
  override function afterExecution( t: Throwable ) {
    // handle the Throwable, do what you need to cleanup
  }
}
Internally the Gosu compiler generates the evaluate() method like so: 
  function evaluate( map: IExternalSymbolMap ) : Object {
    var $failure : Throwable
    if( this.beforeExecution() ) {
      try {
        [method-body] // returns result
      }
      catch( $catchFailure: Throwable ) {
        $failure = $catchFailure
      }
      finally {
        this.afterExecution( $failure )
      }
    }
    return null // only get here if exception not rethrown in afterExecution()
  }

  • Method Details

    • beforeExecution

      boolean beforeExecution()
      Called before IProgramInstance#evaluate().
      Returns:
      false if the program should not be executed i.e., don't call IProgramInstance#evaluate(), true if the program should execute normally.

    • afterExecution

      void afterExecution(Throwable error)
      Called after IProgramInstance#evaluate().
      Parameters:
      error - The exception or error if IProgramInstance#evaluate() terminates abnormally, otherwise null.