The Ever Growing Myth of Passing Objects


Last month, one of my colleagues posed me an intriguing question on passing reference types by “ref”. I am writing this blog post, to share my explanation to a larger set of audience. I have coined the following analogy, to explain the concept of passing reference types.

Think that, you are playing with a kite (object) attached to a thread (pointer), and one of your friends also wants to play with the same.

Pass By Value
You attach an additional thread to the same kite (object), hand it over to your friend and both of you are now playing with the same kite. After a while your friend got bored, detached his thread, and attached it to a new kite (a new object). But, you won’t get affected as your thread is still tied to the old kite.

Pass By Reference
You hand over one end of the same thread to your friend and both of you are now again playing with the same kite. Again, after a while your friend, got bored of the old kite, detached the thread, and attached it to a new kite. But this time, you will also get affected as both of you are now sharing the same thread.

Against popular misconception, objects are not passed at all, only their addresses which are value types are passed between the methods. So, the concept is not anymore different from passing value types. By passing an object’s address by value, you have two pointers for the same object, so you can control its internal state with any pointer. Whereas passing an object ‘s address by reference, you share the same pointer, so you not only can change its internal state, but also can point to a new object.

Comments

Post a Comment

Popular posts from this blog

Chrome Extension - Tab Keeper

Opening too many tabs is one of the biggest memory hogs for the Chrome browser. In my search to find the most elegant solution to this problem, I stumbled upon Jacob Singh's Tab Wrangler extension. It is perfect for my needs, except for the fact that it doesn't store tabs in a feel secure way and sync across all my computers. I didn't find a better way to achieve this, except using chrome Bookmarks. I have modified the code to support this feature, so users can now optionally save all the closed tabs in Other bookmarks  folder in chrome. Recent items are stored in Current folder, and older items are archived based on max tabs setting, to  History folder within different timestamp folders, each containing previous sets of archived tabs.
Read more

The life of a software developer, who can never write a program as efficiently as his manager wants it, for the first time.

During one of my friendly conversations with my father, who is a layman in terms of software development, he asked me, why I had been working almost for a year to develop a simple application called Payroll, which he had always paid from his pocket directly. He felt that, I must work on improving my efficiency as a programmer, as my manager tells me all the time. My blood was boiled, and I felt like opening the 100s of pages specs documents that undergo 10s of revisions, or the long spread sheets containing 100s of earnings and deductions to explain the complexity. But the fact of the matter is, he doesn’t understand most of them, and I also don’t know everything in them. So I thought, why wouldn’t I explain him through a simple story, why it takes so much time to develop a simple software, in general, and why there is a need to change it quite often? Once upon a time there was a product manager, who found an intriguing opportunity and a huge market potential, to develop an ap
Read more

The Never Ending War of Software Constructors and Software Destructors

How many times we as developers curse about the fact that, the defect raised by a tester doesn’t have enough information to reproduce it in the local environment?! I guess, the answer is quite often. If we are dealing with a responsible tester, he/she will provide us with detailed steps, if they are also kind enough, we will in addition get some logs and screen shots, and there ends the matter. Then, we struggle to reproduce it most of the time and would sometimes retort with the most common statement, “Hey! It works in my environment.”, and reject the defect. Sometimes the ball endlessly moves to and fro between the 2 courts. Why are we still living in the era of our great grandfathers, when it comes to debugging defects? I know, most of us are aware of the tools like IntelliTrace that are available to deal with this exact problem. But, I rarely see even developers making use of this tool, to reduce their debugging effort locally, leave aside testers to provide it as par
Read more