Setting a class property to an Enum value - groovy

Question

I have a abstract groovy class that I would like to have an attribute that is of type Enum. However, I'm not clear on how to get it set up.
I have This:
abstract class Person {
protected int heightFeet, heightInches, weight
protected String firstName, lastName
protected OccupationType occupation
protected Person(int hf, hi, w, string fn, string ln, int ocp){
this.heightFeet = hf
this.heightInches = hi
this.weight = w
this.firstName = fn
this.lastName = ln
this.occupation.value = ocp
}
and the Enum looks like this :
public enum OccupationType {
Teacher(1), Administrator(2), Counselor(3), Doctor(4), Nurse(5), ...
OccupationsType(int value) {this.value = value}
private final int value
public int value() {return value}
}
So I Typically get some sort of NullPointerException that it cannot set a value to null object. Not sure what I'm missing, or if this is at all possible.
java.lang.NullPointerException: Cannot set property 'value' on null object
at org.codehaus.groovy.runtime.NullObject.setProperty(NullObject.java:66)
at org.codehaus.groovy.runtime.InvokerHelper.setProperty(InvokerHelper.java:192)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.setProperty(ScriptBytecodeAdapter.java:480)
at ***.****.***.****.<init>(**.groovy:30)
at ****.***.***.****.<init>(***.groovy:10)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.codehaus.groovy.reflection.CachedConstructor.invoke(CachedConstructor.java:77)
at org.codehaus.groovy.runtime.callsite.ConstructorSite$ConstructorSiteNoUnwrapNoCoerce.callConstructor(ConstructorSite.java:102)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:57)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:182)
at buchwalter.oldschoolgame.characters.FighterTest.getFullConcrete(FighterTest.groovy:18)
at buchwalter.oldschoolgame.characters.PlayerTest.shouldReturnGenderType(PlayerTest.groovy:114)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Answer 1

The problem is in your Person constructor. You can't set the attribute of an enumeration. You just pass the enumeration object to the constructor OR you pass the integer value attribute and find the enumeration object which has that value. I've cleaned your example, but it should work when you add the remaining constructor parameters:
// this won't work because 'this.occupation' IS null
protected Person(int ocp) {
this.occupation.value = ocp
}
So either pass the enumeration object:
protected Person(OccupationType type) {
this.occupation = type
}
OR receive an int attribute and find it:
protected Person(int ocp) {
this.occupation = OccupationType.find { it.value == ocp }
}