Help with objects in ArrayList

[BiteMuncher]

Hi, can someone please help.
I have 4 external classes called Cat, Dog etc.
My test program instantiates them i.e. Cat cat = new Cat();
Afterwards I placed them in an ArrayList called 'animals':

animals.add(cat);
""
"'
""

I then created an enhanced 'for' loop:
The idea is to loop through each object and call its public methods.

for(Obect obj : animals)
{
obj.methodName(); //(The idea is that obj represents 'cat')
}

This creates an error. Is it even possible?
Thanks in advance.

[masijade]

Yes, if you define an "Animal" base class and have them extend that (or interface and have them implement that) and then use that class/interface instead of "Object".

[BiteMuncher]

The four external classes in the ArrayList all extend and implement an abstract class called Animal. I cannot create an instance of Animal as it is abstract.

[masijade]

No, but you can reference one. Try it. Change Object to Animal both in the generics definition of the List, and in the for loop.

[JosAH]

The four external classes in the ArrayList all extend and implement an abstract class called Animal. I cannot create an instance of Animal as it is abstract.

Also use a generic List<Animal>; such a list stores animal objects in contrast with a 'raw' List (as you're probably are using now) that stores just Objects.

kind regards,

Jos

[BiteMuncher]

I've now got:

for(Animal : animals)
{
System.out.print("This is: "); Animal.describe();
}

Error: incompatible types
required: Animal
found: java.lang.Object

Don't know if I've got this right.

[BiteMuncher]

Also use a generic List<Animal>; such a list stores animal objects in contrast with a 'raw' List (as you're probably are using now) that stores just Objects.

kind regards,

Jos

Thanks, this seems to have solved it!!

[goldest]

for(Animal : animals)

Does this even work? It should be something like

for(Animal [COLOR="Red"]a[/COLOR]: animals)

Post the whole code if it's not too much lengthy.

Goldest