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TECHNOLOGY
DEVELOPMENT ENVIRONMENT
only the relevant information is presented. Each perspective,
in turn, is itself built up from different views and editors.
An editor is usually in the middle of the screen and is
used to change the code. A view gives additional information
over (or the properties of) a particular part in a
graphical way. Although the concept of perspectives can
look rather abstract at first glance, you will get used to it
quickly once you start to work with it. Within each perspective
just about everything can be configured as
desired, such as the selection, position, arrangement of
the different views and editors. In this way you always
have the appropriate information at your fingertips that is
the most relevant to you at that time.
Getting started with Java
Eclipse is eminently suitable as a development environment
for Java-applications. With this there is a central
role for the Java-perspective. At the far left we find the socalled
Package Explorer. This is a kind of explorer, which
shows the contents of all the projects in the workspace
selected earlier. Think for example about source code,
graphics and configuration files, but also imported
libraries and information regarding the Java Runtime
Environment being used. From the Package Explorer we
select which files we want to view or edit.
Figure 2.
The package explorer
offers an overview of
all the elements in a
project.
(fixing errors) and adding or maintaining code from others.
Because much information relating to a particular task
is not pertinent to another task, it is only presented when
carrying out the relevant activity (read: in the relevant perspective).
This way the screen remains uncluttered and
For more information regarding the open file in the editor,
we can use the outline-view. Three separate parts can be
distinguished in here: at the top we can see the package
that contains the class. Underneath that is a list with
import declarations, which can be collapsed to make
room for the rest. The last part is the most interesting of
these three. It provides a detailed overview of the construction
of the relevant class. This includes all variables
and methods together with all accompanying information.
A helping hand
Eclipse has a feature with the name ‘auto completion’,
which will show all relevant options within a class. It suffices
to type the letters ‘get’ and hit the Ctrl key and
space bar to list all the methods that begin with ‘get’.
And if this is not enough, a separate pop-up screen also
displays the accompanying java-documentation.
The handy auto-completion window is also used in a different
context, where the feature is called ‘quick assist’.
This is mainly useful to quickly change the code when the
compiler has found an error or has issued a warning. All
errors and warnings are, incidentally, also clearly presented
in the ‘Problems’-view. With the key combination
‘Ctrl+1’, Eclipse immediately proposes a number of possibilities
for solving the problem.
Figure 3.
You are kept informed
of everything while
debugging.
Tracking down errors
No matter how clever a development environment is, a
sizable amount of code will always contain a few
errors. Once we’ve established that there is an error it
becomes the objective to determine the cause and that
is where the debug-environment comes in. Debugging
is so important that a separate perspective is dedicated
to this activity. By doing so, space is made available for
information that is indispensable while debugging. Naturally
we find here everything with connection to actual
values of variables, breakpoints that have been set, etc.
It also presents all running threads and their states. We
can terminate, continue or restart threads as we please.
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elektor electronics - 10/2006