The Facade
I never dared to enter a bank during my school days. There used to be a security guard standing at the entrance with a rifle. I was under the impression that banks are only meant for the rich and famous. However, I got a chance to go to the bank at the end of the 11th class to pay the exam fee. I entered the bank with a lot of curiosity. I was expecting loads of money scattered across the bank premises.
It was a big disappointment. I didn’t see even a single coin. What I saw were several counters and lots of people moving around. I was totally confused. I didn’t know where to start the process of getting a challan.
With a lot of courage, I asked a person for help. He filled in the challan form and directed me to a counter. I submitted the form to the counter, after waiting for my turn in the queue. The clerk took the form, issued a token, and asked me to come after an hour.
I passed the time observing the counters and the other people. I found that not many people really knew the procedure to get the job done. They were moving from one counter to another counter. Almost everyone was looking for help from others.
After an hour, I went back to the counter. However, the clerk told me to go to another counter to collect the challan. I followed the word and collected the challan. There was still one more step to finish the job. I needed to get a seal on the challan. After asking a couple of people, I found the person to get the job done.
On that day, I really felt that I learned a life skill … getting a bank challan. I noted down the whole procedure in my personal journal for future reference.
One more year passed and I again went to the bank for challan for the 12th board exams. This time I was confident as I knew the procedure. But the confidence evaporated within no time after seeing that the number of counters, their locations and etc were not in the way they were a year ago. I had to depend on help from multiple people to get my challan, this time too!
I am sure that many of us might have gone through this kind of experience. The banks keep changing the roles and responsibilities of the counters. Of course, they do it for a reason. They might have started offering new services, or there might be a change in the staff composition and etc., My only problem is that every time they make such changes, customers are forced re-learn the whole process of banking. Can the bank handle those internal changes without affecting the customers?
Like in the case of the bank, software systems usually consist of several components. Exposing these components directly to the client applications is as bad as exposing the internal banking procedure to the customers. Every time the system goes through a change, all the clients are forced to change as well.
Banks found a solution! They set up help-desks in such a way that the customer only interacts with the help-desk for all their banking needs. It is the help-desk person who knows the internal process, not the customer! What goes internally among the bank counters is made transparent to the customer. The person at the help-desk accepts the request along with the required documents and gets the job done … simple! If there is any change in the bank procedure, only the help-desk person needs to be retrained! Customers are happy!
Software system designers also need to offer such a consistent entry to the system. Client applications should only be aware of the entry point. The entry point interacts with system components, behind the curtains, to fulfill the client’s request. The implementation of the entry point may vary from time to time as a consequence of the internal changes, but its interface should not go through frequent changes.
I am sure, you already guessed what I am talking about. Yes, it is about the facade!
The facade is one of the structural design patterns proposed by the Gang of Four. Its objective is to hide the internal implementation of the business processing from the clients. It makes the service providers and the clients stay coupled, but only loosely! It gives better returns on the effort that the clients put in.
