compareTo

[adam Lui]

source: K & B page 553

class DVDInfo implements Comparable<DVDInfo> {
String title;
String genre;
String leadActor;
DVDInfo(String t, String g, String a) {
title = t; genre = g; leadActor = a;
}
public String toString() {
return title + " " + genre + " " + leadActor + "\n";
}
public int compareTo(DVDInfo d) {
return title.compareTo(d.getTitle());//Line 1----------compareTo again??
}
public String getTitle() {
return title;
}
// other getters and setters
}
 

I understand what line 1 does (compareTo), but doesnt it recursively invoke compareTo itself (possible for any method?) or it is invoking some other compareTo in extending classes?

[Kelvin Chenhao Lim]

Not sure what you mean. That statement is calling the compareTo method of String, since title is a String reference. All classes that implement the Comparable interface have a compareTo method.

To answer your secondary question, yes, recursive method calls are fine in Java. This includes infinite recursive loops, which the compiler will accept but will cause the JVM to eventually throw a StackOverflowError.

[Burkhard Hassel]

Howdy ranchers,

the invokation indicated is not recursive. It calls a method of a differnt class. To be truely recursive it has to call itself.
You can for example calculate the faculty n! of a number by using a recursive method.

Yours,
Bu.