Using Javabeans to Produce the Bars
Now that we have the basic technique in place we can write a JavaBean which
facilitates making the bars. For a single horizontal bar we need a method
like this (the parameters should in this case be self-explanatory):
public String getHbar(int length, int width,
String color, String label)
[The lines above are one line. It has been split for formatting
purposes.]
And for the vertical bar we need this method:
public String getVbar(int length, int width, String color, String label)
These methods simply return the HTML for a single bar.
At the same time we'll add a possibility to define the font family and size
for the chart. To adhere to common standards we'll use a style sheet definition.
To set the font information and to retrieve the style sheet we need methods like
this:
public void setCSS(String fontFamily, String fontSize)
public String getCSS()
You can find the code for the JavaBean
here. A JSP-page which
uses the bean is this:
<jsp:useBean id="graph" class="htmlgraph.Graph" scope="request" />
<%
graph.setCSS("Verdana","10px");
%>
<html>
<head>
<%=graph.getCSS()%>
</head>
<body>
<table
cellspacing=0 cellpadding=1 border=0>
<tr><%=graph.getHbar(300,10,"red","NBC")%></tr>
<tr><%=graph.getHbar(200,10,"green","CBS")%></tr>
<tr><%=graph.getHbar(320,10,"orange","CNN")%></tr>
</table>
<table cellspacing=0 cellpadding=1 border=0>
<tr>
<%=graph.getVbar(75,20,"red","ASP")%>
<%=graph.getVbar(87,20,"green","JSP")%>
<%=graph.getVbar(45,20,"orange","EJB")%>
<%=graph.getVbar(10,20,"black","CGI")%>
</tr>
</table>
</body>
</html>
This will produce these bars:
Note that by changing the values for cellspacing and cellpadding you can
fine-tune the layout of the bars.
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