com.imsl.chart
Class ChartServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          com.imsl.chart.ChartServlet

All Implemented Interfaces:

Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public class ChartServlet

extends javax.servlet.http.HttpServlet

The base class for chart servlets.

This class requires a servlet container.

The behavior of this class depends on the version of the Java runtime being used.

• JDK1.4 or later. Images are rendered using the standard class javax.imageio.ImageIO. This class can be used on a headless server. Java runs in a headless mode if the system property java.awt.headless=true. This class turns off caching in the ImageIO class (calls javax.imageio.ImageIO.setUseCache(false)).
• JDK1.3 or earlier. Since the ImageIO class does not exist in older versions of Java, this class requires the Java Advanced Imaging Toolkit (JAI) and a running windowing system to create images. It will not work on a "headless" server.

See Also:

Chart Programmer's Guide: Servlets, Java Servlets, Java Advanced Imaging Toolkit, Serialized Form

Field Summary

static long

serialVersionUID

Constructor Summary

ChartServlet()

Method Summary

protected void	doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Returns the chart as a PNG image.
protected Chart	getChart(javax.servlet.http.HttpServletRequest request) Returns the chart found in the session saved with the key "chart"+id, where id is the value of the "id" parameter in the request.
void	init()

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doOptions, doPost, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

ChartServlet

public ChartServlet()

Method Detail

doGet

protected void doGet(javax.servlet.http.HttpServletRequest request,
                     javax.servlet.http.HttpServletResponse response)
              throws javax.servlet.ServletException,
                     IOException

Returns the chart as a PNG image. The HTTP request parameter "id" selects the chart.

Parameters:

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

response - an HttpServletResponse object that contains the response the servlet sends to the client

Throws:

javax.servlet.ServletException

IOException

getChart

protected Chart getChart(javax.servlet.http.HttpServletRequest request)

Returns the chart found in the session saved with the key "chart"+id, where id is the value of the "id" parameter in the request. This method can be overridden to change how charts are communicated to this servlet.

Parameters:

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

Returns:

the chart to be rendered or null if the chart cannot be found.

See Also:

JspBean

init

public void init()
          throws javax.servlet.ServletException

Throws:

javax.servlet.ServletException