Re: Can we over-load "+" in Java?
Shawn wrote:
Hi,
Suppose I have following classes:
class Person {
...
}
class Team {
//how to have a member variable which holds an array of objects of
Person?
...
}
Person person1= new Person("John Smith");
Person person2= new Person("Linda King");
Person person3= new Person("Ed Johnson");
//here is what I want:
Team BestTeam;
BestTeam = person1 + person2;
//now an object of class Team was created and this team has the two people
BestTeam = BestTeam + person3;
//now Ed Johnson joined the team
BestTeam = BestTeam - person3;
//now Ed Johnson left the team
Can we overload "+" and "-" to achieve the effect above? If not(which is
my feeling), how can we achieve something similar? If we use a method
(say,join(), left()), please give me full implementation of the method?
Java does not allow user-defined overloading of operators. Even if it
did, I would argue against using + for anything other than addition of
numbers, - for anything other than subtraction of numbers etc. I've seen
C++ code that uses operators for arbitrary functions, and find it quite
unreadable.
For this sort of task in Java, I would design a class Team with methods
such as "add", "remove", "isMember", and possibly a method returning an
iterator over the members.
Team bestTeam = new Team();
bestTeam.add(person1);
bestTeam.add(person2);
bestTeam.add(person3);
bestTeam.remove(person3);
etc.
Inside bestTeam, I would use e.g. a java.util.Set, with implementing
class chosen based on the sort of operations, to remember the current
members.
Patricia
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