Re: this

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 29 Apr 2012 12:51:08 -0700
Message-ID:
<jnk63c$e5j$1@news.albasani.net>
Tsukino Usagi wrote:
....

One of the more interesting usages of "this" remains passing a reference to an
object versus defining scope. It can be used to create a way to pass a
function as an argument. For example, if we have a well-known function name


Excellent example for several reasons.

encapsulated as a class (think "Thread", "Runnable", or "Callable"):

class Callable { callme(Object o) { /* code here */ } }


Quibble: This should be an interface, not a class, and we should declare
pedagogical examples 'public', and most certainly the method should be:

/* not to be confused with
<http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Callable.html>
  */
public interface Callable<T>
{
   void callMe(T client);
}

class Println extends Callable { callme(Object o) { println(o); } }


public class Println implements Callable<Object>
{
   @Override
   public void callMe(Object client)
   {
     System.out.println(client);
   }
}

The pattern of single abstract method (SAM) interfaces is so prevalent and
useful that Java will introduce a sort-of functional syntax for it in Java 8.

--
Lew
Honi soit qui mal y pense.
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