lt.monarch.chart.servlet
Class ChartServlet

java.lang.Object
  HttpServlet
      lt.monarch.chart.servlet.ImageServlet
          lt.monarch.chart.servlet.ChartServlet

public abstract class ChartServlet
extends ImageServlet

Passes chart images to the browser. User is responsible just for creating the chart object. Servlet takes care of the rendering process, image creation, encoding and transmission to the browser.

Field Summary

Modifier and Type	Field and Description

Fields inherited from class lt.monarch.chart.servlet.ImageServlet

encoder

Constructor and Description

ChartServlet()

Method Summary

Modifier and Type	Method and Description
protected abstract View	createChart(HttpServletRequest req) Requests a chart be created for the HTTP request.
protected java.awt.Image	createImage(HttpServletRequest req) Triggers the createChart method.
protected java.awt.Dimension	getPreferredSize() Queries the size of the chart, to be served.

Methods inherited from class lt.monarch.chart.servlet.ImageServlet

doGet, getEncoder

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ChartServlet

public ChartServlet()

Method Detail

createChart

protected abstract View createChart(HttpServletRequest req)
                             throws ServletException

Requests a chart be created for the HTTP request.

Parameters:

req - servlet request

Returns:

chart to be returned to the browser

Throws:

ServletException - if the request for the GET could not be handled

getPreferredSize

protected java.awt.Dimension getPreferredSize()

Queries the size of the chart, to be served. This method has to be overridden to change chart size.

Returns:

preferred chart size

createImage

protected final java.awt.Image createImage(HttpServletRequest req)
                                    throws ServletException

Triggers the createChart method. The returned chart is then rendered into an image and the image is returned.

Specified by:

createImage in class ImageServlet

Parameters:

req - an HttpServletRequest object that contains the request the client has made of the servlet

Returns:

the Image object containing rendered chart

Throws:

ServletException - if the request for the GET could not be handled