JClass Chart Overview
Introduction
·
Feature Overview
·
Setting CLASSPATH
Using the Java Programming Language
·
Compiling a Program
Distributing JClass Chart Applications
Introduction
JClass Chart is a charting/graphing component written entirely in
Java. JClass Chart is based on the award winning XRT/graph and Olectra
Chart products from KL Group. However, JClass Chart is not a simple
"port" of those products. JClass Chart has been designed from the
ground up to take advantage of object-oriented techniques, but not
at the expense of usability or efficiency.
JClass Chart offers users a choice of interaction techniques
that simply are not available in other components. In all,
there are four different ways of interacting with JClass Chart:
- as a component user by setting JClass Chart properties
programmatically.
- as an OO developer by using and extending JClass Chart objects.
- as a Bean developer/user by setting JClass Chart properties
using a third-party Integrated Development Environment.
- as a Web page developer by setting JClass Chart properties
exposed through HTML parameters.
JClass Chart is available as either a JDK 1.0.2 Transitional Bean or
a JDK 1.1 Java Bean. The API and event handling is
identical for both versions, eliminating the need to re-code your Java programs.
Feature Overview
JClass Chart is remarkably flexible. Shown below are just some of
the unique things that can be done with JClass Chart:
- multiple data series
- multiple chart types on the same chart
- multiple data sets plotted against different axes
- multiple x and y axes
- three-dimensional appearance for bar, stacking bar and pie charts
- rich text (JCString) for headers, footers, axis titles and even axis
annotations. Developers can mix text font, color, placement
with images and URLs.
- chart interactions including rotation, zooming, scaling, translation
and point editing
- unmatched axis labelling and layout options
- flexible external data model, with common data sources already
implemented (files, URLs, input streams).
The chart types supported by this release of JClass Chart are Plot,
Scatter Plot, Area, Bar, Stacking Bar, Pie, Hi-Lo, Hi-Lo-Open-Close
and Candle.
Each of these chart types can be controlled and modified in a
number of ways. Each data series has a chart "style" associated
with it that controls the appearance of the data series, including
the fill color for bar charts, the point style for plot charts,
and so on. Bar, stacking bar and pie charts all have three-dimensional
attributes that can be used to give depth and perspective to the
chart.
JClass Chart supports external data sources. This means that an
existing data object can be attached to JClass Chart. The data
object can be loosely-coupled or tightly-coupled to JClass Chart.
In the loosely-coupled case, the data is retrieved from the
data source when the data source is attached. If desired, the
chart can update the data source when values are changed. In
the tightly-coupled case, the data source can inform chart when
data has changed.
Setting CLASSPATH
Note: If you are using the MS-Windows version of JClass Chart that is self-installing,
your CLASSPATH statement is automatically set up during the installation process.
The jcchart{xxx}-classes.zip file can be located anywhere on a user's computer or on a Local
Area Network (LAN), but you must indicate to the Java interpreter where it can find the Java classes
it contains. This is done by setting the CLASSPATH environment variable. The CLASSPATH environment
variable consists of the names of directories containing compiled Java classes. The following examples
will help you set CLASSPATH properly on your system.
If you are using JClass Chart in a development environment, do not unarchive the contents of the
jcchart{xxx}-classes.zip file--its contents are automatically read by Java.
If your CLASSPATH environment variable is not set up correctly, see your system administrator or the
"Update environment variables" section specific to your computing platform. This information can be
found through the Java Developers Kit Web page at http://www.javasoft.com/products/jdk/.
Before attempting to use JClass Chart, you must be able to compile Java applications or applets. Make
sure you can compile and run simple Java applications or applets before you begin to use JClass JClass Chart.
Consult the Java JDK documentation for assistance in determining the location of the Java compiler (javac)
and the Java class files.
The following are descriptions for configuring CLASSPATH for specific operating systems:
Windows 95
Add a line to your AUTOEXEC.BAT file that points to the directory where jcchart{xxx}-classes.zip
is installed. If jcchart{xxx}-classes.zip is installed in a directory called \foo, you would add
something similar to the following to your AUTOEXEC.BAT file:
set CLASSPATH={references to other
programs};C:\foo\jcchart{xxx}-classes.zip
Windows NT (3.51 and higher)
Assuming that jcchart{xxx}-classes.zip is installed in a directory called \foo, add the CLASSPATH
statement to a Windows NT system by doing the following:
- Double click Control Panel. The Control Panel window opens.
- If you are using Windows NT 3.51, Double click System. The System dialog is displayed. If you are using
Windows NT 4.0, double click System. The System Properties dialog appears. Click Environment.
- Search the User Environment Variables (or User Variables in Windows NT 4.0) list for an existing CLASSPATH
statement.
If a CLASSPATH statement exists, select it. In the Value field, add the following to the existing statement:
C:\foo\jcchart{xxx}-classes.zip
If no CLASSPATH statement exists, in the Variable field, type:
CLASSPATH
and in the Value field, type:
C:\foo\jcchart{xxx}-classes.zip
- Click OK.
Tip: If you are going to compile Java programs in the same directory that contains Java .class files,
add a period to the CLASSPATH statement to point the Java compiler to look for .class files in the current directory,
as in the following example:
C:\foo\jcchart{xxx}-classes.zip;.
This method will work on all computing platforms.
Note to Browser Users: If you set the CLASSPATH for your entire session, the CLASSPATH will be picked up by
the Web browser as well.
Using the Java Programming Language
Java is both a compiled and an interpreted language. After writing a Java program using a text editor, save it as a
source file with the extension .java. When this source file is run through the Java compiler, it compiles
the file into a .class file. Unlike .exe or .com files, these compiled .class files are
not directly executable under any operating system, because they do not contain machine-language code that can be
understood directly by the microprocessor. Instead, they are compiled into a byte-code format consisting of
machine-language instructions designed for a virtual microprocessor. This virtual microprocessor is the Java
Virtual Machine, which interprets the byte-code into a machine-language code that can be understood by your
system’s microprocessor. As long as the Java Virtual Machine software exists for a computing platform, any Java
programs you create will be able to run on that platform.
If your Java development environment has been set up correctly, a Java
program can be compiled by entering the following at a command prompt:
javac foo.java
Compiling a Program
Java allows for two distinct program types: stand-alone applications and applets. Stand-alone applications can be
run directly on a system containing the Java interpreter program (java), while applets can be inserted and
run from Web pages when viewed through a Java-capable browser. JClass components can be used with both types of
Java programs. Ensure you can compile and run simple Java applications or applets before you begin to use JClass
Chart. Consult the Java JDK documentation for assistance in determining the location of the Java compiler
(javac) and the Java .class files.
Distributing JClass Chart Applications
You can freely distribute
end-user Java applications or applets you build with JClass Chart
components under certain restrictions.
For more information, read
the License Agreement at the beginning of this manual for complete
details.