Service out and actually making the event happen. Trigger

Service orientated

Service-orientated methods are used so that various
applications are able to reprocess components. Altered types of software
applications can advantage from these facilities, for instance they can appeal
information from a record.

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Time driven

Time driven programming is a kind of computer programming
that is regularly used in present computing, where code implementation is
achieved by the computer clock. This programming notion is primarily used for
safety-serious programs, since the presentation of the program is highly
deterministic.

Event handlers

Event handlers are made in code form and they determine what
is to happen if a user is to (for example) make an action with the mouse by
clicking a specific button. One the button is clicked by the mouse the event
handles the action by carrying it out and actually making the event happen.

Trigger functions

When using event driven programming, trigger functions are
used to select which type of event handler should be run according to the event
occurring.

Events

An event is the result of an action. There are loads of
events that trigger the event handlers to run. For example:

·        
A mouse clicks events include left click, double
left click, right click and hover

·        
Keyboard events include key press, key down and
key up

·        
HTML object events happens when a user clicks on
an object that may be connected to a linked web page

·        
Form events have to do with the load event when
the form shows up for the first time and the activate event used when a form
regains focus. Form events also triggers event handlers intended for objects on
the form for instance, defining the accept button code for when the user uses
the enter key on a form.

·        
A user interface event happens with anything
that the user does with a GUI operating system or to the form of a running
program.

Event loops

Event loops are needed so that they can continuously test
the user interface to detect whether anything has happened, for instance
clicking on a button or typing into a text box. If events are detected, the
event is then passed to the trigger functions which would then call the best
event handler that is suitable to run any code in the program that’s designed
and written for the event.

Forms

Forms are a major feature and are used to hold all the
controls the programmer used to create programs. Forms can also be a type of
control that has a collection of events that may be used by the programmer.
Using these forms can be a strong way to control a program mostly when a
program loads and ends. One example of a form event is Load, which occurs when a form is first used. The load event is
useful for code in order to set variables, to be able to set default values and
other matters that is needed to be done just once. Another example of a form
event is activated which occurs whenever
the form has received focus (is brought up). An activated event is used as an
advantage for updating a form whenever a user returns to it from another form.

Flexibility

Flexibility is an advantage for a programmer as they have
control over codes and how they can start them. Each object has choices of
events that the program can respond to. The events allow you to have good
control over what the program will respond to when the user does something. For
example when using a text box, there is usually a choice of events that is
given so that fine programming has good control over anything typed into it.

Suitability for graphical interfaces

Event driven programs are suitable for graphical user
interfaces when paired as they work well with each other. A GUI allows the
users to have a good variety of graphical choices and menus that are used with
the mouse or keyboard or any other input device, with no set sequence that the
user has to follow. Controls used will react to events with code that is suitable
for each event and for how the program is likely to be used.

Simplicity of programming

Event driven programming language is able to make
programming seem straightforward compared to traditional flow driven languages,
because the programming language is very visual.

Ease of development

Program development can be easy with an event driven
language as the programmer would only need to work on one event of one control
at a time. Flow driven languages must be complete before they can run and be
tested, whereas an event driven language will run with as little as only the
code for a single event completed.

Disadvantages

Some event driven languages have long and complicated
commands that programmers would have to use, and as a downside, sometimes
programmers would need to type them all up. Testing would be essential in order
to make sure the program works as normal. Also event driven languages can be
quite slow due to the fact that processing power gets soaked up by event loops,
and more processing power is taken up by the trigger functions.