Wht is call chaning?

Question

hi,
wht is call chaning?
is this work's in java
sum(sum(sum(2)));

Answer 1

Please use code tags next time. Either use the button labelled code, above the textarea while posting or manually wrap your code in code tags like this:
{code}
//Your code here
{code}
to have it formatted like this:
    //Your code hereChaining basically allows you to call a method on the object returned by another method call without needing to use a reference variable. For example, you can write:
String testString = "  My String  ";
String testString2 = testString.trim(); //returns "My String";
String testString3 = testString2.toUpperCase(); //returns "MY STRING";
String finalString = testString3;As you can see, testString2 and testString3 are not being used beyond these three statements; we actually only want testString and finalString.
The same thing can be written using method chaining as:
String testString = "  My String  ";
String finalString = testString.trim().toUpperCase();                            And this will only work for methods that return an object. If the method call returns a primitive or nothing ( signature has void ), then you obviously can't call anything on that.
That's why your code fails to compile:
hum ref=new hum();
ref.sum(5).sum(5);sum() returns nothing. If you modified it to return int, that also would not work since it's a primitive. If you returned Integer, you could probably call a method on that. But not sum() since sum() isn't defined in Integer.
And no, it's not the same as concatenation. That's something to do with strings.
Edited by: nogoodatcoding on Oct 30, 2007 12:49 PM