Properties under jWPS
Object-oriented design Is based on a few
fundamental principles. One of the most basic is that there are object
which have properties associated with them. So for example, an OS/2
object might not allow copies of itself to be made, or it might not be
printable (how would you print your mouse?) Not surprisingly, OS/2 WPS
objects have properties. There are two basic ways that one may make
properties available. Either have a set and get method for each
property (OS/2 uses set/query pairs mostly, but it is the same idea),
or have key/value pairs, where the key is usually an integer and the
value varies as a property – maybe a string value for a title or
logical value to control whether the object can be dragged). The plus
with the first method is that is immediately clear which properties are
there. The downside is that it does not scale well. Having 200 or so
methods to set/get values is a nightmare. The latter method requires
very few methods but many keys and a knowledge of what they can do.
This is the best that can be done and the onus is then on the
documentation to keep it clear.
OS/2 of course used not quite either of these systems, having
certain set/get pairs for some properties, key value pairs for others
and still an even more opaque system of bit switches for others.
Setting and Getting Properties
There is a single point of access for properties. This is set of
methods of the form
setPropertyXXX(int key, <value>) Where
XXX is the type of the property and
<value> is of this type. So for example there are methods named
key, String value) and as well
etc.. The key constants are defined in JWPConstants.
There is a table of them
included in this document and that is the reference for the system.
One other way of setting properties exists in OS/2 and this a so-called
setup string. You do not need these, although if you are really
insistent there is a method supplied to let you set a setup string. If
you don't know what these are, there is no reason for you to try and
learn them. This is included because there is quite a bit of arcane
voodoo involved in creating these and people who are porting their apps
to jWPS might have very painstakingly constructed setup strings. These
can just be dropped in place and used.
There are several views whose properties are defines in the views
package. If you need a view on an object, you instantiate it like this.
This example gets the settings notebook view properties:
// whatever you need in your program
JWPObject myObject = new JWPObject("some id or file name");
SettingsViewProperties svp = new SettingsViewProperties(myObject);
// let's set this as the default for this object:
// .. drive on ...
Let me stress that these are the properties of the view , not the
view itself. For instance the
object has properties for the font, the color of text used by shadow
objects and such. In the table are listed the view objects. You might
ask if there are there other views