Java concatenating various methods (not the method to concatenate strings)

Question

When I write a class with several voids:

public class MyObj {
    public void doSomething() { /* does something */ }
    public void doSomethingElse() { /* does something else */ }
    ...
}

I can use the following code:

MyObj myObj = new MyObj();
myObj.doSomething(); // does something
myObj.doSomethingElse(); // does something else

But if I write the class like this:

public class MyObj {
    public MyObj doSomething() {
        // do something;
        return this;
    }
    public MyObj doSomethingElse() {
        // do something else;
        return this;
    }
}

I can use the following code to accomplish the same task:

MyObj myObj = new MyObj();
MyObj.doSomething().doSomethingElse(); // does something and does something else.

I've seen the 2nd form in JavaScript (jQuery):

$("#myDialog").dialog().focus().mySuperLongNameHomeMadeBullshitFunction().remove();

So my question is, in Java, what are the pros and cons of using the concatenating form or the standard? (I'm really not going to change to the second, just curious, as we all are).

FYI, that form of chainable method invocations is often called a "Fluent API", and it is gaining in popularity. — Kevin Welker, Mar 07 '13 at 19:51
See: http://stackoverflow.com/questions/1103985/method-chaining-why-is-it-a-good-practice-or-not — Alex, Mar 07 '13 at 19:51

score 4 · Accepted Answer · answered Mar 07 '13 at 19:51

4

Method chaining allows you to call the methods in a single expression.

This can be useful in situations where you cannot use multiple statements -- e.g., this() and super().

answered Mar 07 '13 at 19:51

Andy Thomas

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score 0 · Answer 2 · answered Mar 07 '13 at 19:53

0

Using method chaining can allow to create some DSL using fluent API and create clearer code.

It can allow to be more concise and more meaningful while doing the exact same thing.

answered Mar 07 '13 at 19:53

benzonico

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A nice article about this : http://www.martinfowler.com/bliki/FluentInterface.html – benzonico Mar 07 '13 at 19:54

Java concatenating various methods (not the method to concatenate strings)

2 Answers2