//==================================
//x2031     groovy smart objects w expando events



println "//x2031     ex-expando-events-gen-v1.groovy"

println """
    ex-expando-events-gen-v1.groovy
          x111c groovy bound property example - https://blog.mrhaki.com/2009/08/groovy-goodness-bound-and-constrained.html
        shows the flexibility of event messaging in requirements modeling using bound property event listeners
           in the example
           the toyota vehicle has bound properties
           the owner listens for changes in the toyota properties 
        this model has 2 independent objects, one listening for events on the other in a single Java process 
        for modeling purposes, this simple method can proxy the concept of independent processes linked by event messages 
            jim mason - jmason900@yahoo.com 
"""
import groovy.beans.*

class Owner implements PropertyChangeListener {
    boolean carPriceChange
    Car aCar
    String name
    String toString() {
        "owner = $this.name and the car is ${aCar.toString()} "
    } 
    public void propertyChange(PropertyChangeEvent e) {
        String propertyName = e.getPropertyName();
        println "debug>> e = ${e.toString()}"
        if ("price".equals(propertyName)) {
           println "\n Event >> Owner $this.name detected car ${e.source.brand} price changed to: ${e.newValue} from: ${e.oldValue} \n\t the car is ${aCar.toString()} \n"
        }
        if ("automatic".equals(propertyName)) {
           println "\n Event >> Owner $this.name detected car ${e.source.brand} automatic transmission type changed to: ${e.newValue} from: ${e.oldValue} \n\t the car is ${aCar.toString()} \n"
        }
    }
}

@Bindable
class Car {
   int numberOfDoors
   @Vetoable String model
   @Vetoable String brand
   @Bindable boolean automatic
   @Bindable double price
  
   String toString() {
     "[Car details => brand: '${brand}', model: '${model}', #doors: '${numberOfDoors}', automatic: '${automatic}', price: '${price}']"
   }
}

import groovy.beans.*
import java.beans.*
 
def toyota = new Car(brand: 'Toyota', model: 'Verso', price: 28919, numberOfDoors: 5, automatic: false)
toyota.propertyChange = {
 if (it.propertyName == 'price') {
  println "The price has changed. Inform sales the new price is '${it.newValue}'."
 }
}
toyota.vetoableChange = { PropertyChangeEvent pce ->
 if (pce.propertyName == "brand") {
  if (!(pce.newValue in ['Toyota', 'Lexus'])) {
   throw new PropertyVetoException('New value is not Toyota or Lexus', pce)
  }
 }
 if (pce.propertyName == "model") {
  if (pce.newValue ==~ /.*\d+.*/) {
   throw new PropertyVetoException('No numbers in model names allowed.', pce)
  }
 }
}
 
toyota.price = 30995
assert 30995 == toyota.price
 
toyota.brand = 'Lexus'
assert 'Lexus' == toyota.brand
 
try {
 toyota.brand = 'AUDI'
 assert false: 'We should not be able to set this value.'
} catch (PropertyVetoException e) {
 assert true
 println " could not set brand to AUDI. car brand is ${toyota.brand}"
}
 
try {
 toyota.model = 'A5'
 assert false: 'We should not be able to set this value.'
} catch (PropertyVetoException e) {
 assert true
 println " could not set model to A5. car model is ${toyota.model}"
}

def anOwner = new Owner()
anOwner.name = "Jim"
println anOwner.toString()
anOwner.aCar = toyota
println "\n car was purchased \n    ${ anOwner.toString() }  \n "

// how to add an propertyChangeListener to an object in groovy

toyota.addPropertyChangeListener(anOwner)
toyota.automatic = true
toyota.price = 44000
toyota.automatic = true              // no pce fired because the attribute state is the same