The term “Context” in programming? [closed]

Answer 1

Context refers to the execution context, which is the symbols reachable from a given point in the code, and the value of those symbols in that particular execution.

Context is an important concept because:

1. Executable units (functions, procedures, instructions) may produce different results or behave differently under different contexts.
2. The larger or more complex the context, the more difficult to understand what a piece of code does (that's why global variables are shunned upon).

You do not have to write context classes or pass context parameters. Any parameter passed to a function/method becomes part of the execution context when it is invoked.

Even though you're not an English speaker, I recommend you go through a copy of Code Complete for a gentle yet thorough introduction to concepts like context, modularity, coupling, cohesion, and so forth.

Answer 2

3 yrs later so maybe a little late, but, maybe this thread would help you. It illustrates that the word "context" has a technical meaning in programming (not just a plain English meaning).

What programming languages are context-free?

Not sure if you can use it as an example and pull some information out of it or not. I too would love to hear a language agnostic explanation of the technical programming term "context"

Edit : Or it at least shows that the term "context" can be applied in a technical, programming context (no punn intended). Possibly in more than one concrete application of the term.

Answer 3

i always think of context as a particular state relevant to the object or construct i am working with.

For example, when you are using drawRect in a view (where all drawing must be done for a view) you must always get the currentGraphicsContext into which you will issue your core graphics statements. This context contains things like bounds of the view, the stroke colour, the stroke thickness for drawing a line, the fill color for filling a closed Path etc. this context (like most others) is just the current state at this point in time. so think of the graphics context in this case as just a set of state such as

stroke thickenss is 1.5 pixels fill color is black bounds of view is (155, 200) stroke color is Red

Its basically the state at the current point in time ...

Answer 4

This is 2015 - may years after this thread began.

Nonetheless, I am posting this message to help anyone out there like me that is Struggled to understand "Context"

By no means do I claim to have used Context in Java programs - so its entirely up to you to write Context out in hard coding So here goes :-

"Conceptually context" is the same "as tell me more" When a client makes a request to server - in order to carry out the request the server says "give me some more info so that i can help you". Thus, alongwith the request, the client provides a bundle of details. The server picks and chooses from the bundle all pieces of info required to serve the request. This bundle is what is called "Context"

E.g.

Patient goes to doc and says treat_me ( "I have a headache" ) Doc office gives the patient a form to fill. Patient fills form. The form is used by the doctor to carry out the "treat_me" request.

Here is how the request now looks :

treat_me ( "i have a headache", filled_form_num_23321 ) 

Here is how filled_form_num_23321 looks :

Q.What lead to the condition ? A. 10 pegs of neat Scotch last nite
Q.Patient name ? A. Joe Bigdrinker
Q.Age ? 98

In this transaction filled_form_num_23321 is the "context".

Hope this helps in clarifying the concept of "Context".

Answer 5

To give a practical example. Lets say you have a certain webpage to fetch/render some information based on the user (thats logged on) and language of the browser. The logic of fetching the information is independent from the user and the language. Your page will receive a user and a language ... for the logic it doesnt matter if it is me or you or english or spanish.

Some pseudo code:

class FooPage
{
    void handleRequest(RequestContext context)
    {
        User user = context.getUser();
        Locale locale = context.getLocale();

        … do some logic based on the context
    }
}

Its not that difficult, but it takes some time to understand the concept

Answer 6

Context can be seen as a bucket to pass information around. It is typically used to pass things not necessarily tied directly to a method call, but could still be pertinent. A layperson way of describing it might be "stuff you may care about".

For e.g. if you were writing a service to update a value in a db, you'd probably pass in the record id, and the new value.

If you want generic interfaces, you may also define a context to pass, such that the service can perform arbitrary business logic. So you may include a user authentication, the user's session state, etc... in the context, as the service may perform additional logic dependent on these values.