Tuesday Mar 10, 2009
Tomacco
I had another programmer come over and ask me a question that centered around inheritance. Specifically, trying to understand how/why subclass Bletch could see property 'bar' from superclass Foo:
public class Foo {
int bar;
...
}
public class Bletch extends Foo {
public int count() {
return bar++;
}
...
}
I reminded him how inheritance works (he is new to OO), but we also discussed composition. As an example I worked up to the Tomacco plant: it extends Tomato, but contains an instance of Tobacco so that it can respond to hasNicotine():
public class Tomacco extends Tomato {
Tobacco t = new Tobacco();
public boolean hasNicotine() {
return t.hasNicotine();
}
...
}
Posted at 01:15PM Mar 10, 2009
by lance in Java |
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