prajna.chart.jfreechart

Class ChartTag

java.lang.Object

javax.servlet.jsp.tagext.TagSupport

prajna.chart.jfreechart.ChartTag

All Implemented Interfaces:

java.io.Serializable, javax.servlet.jsp.tagext.IterationTag, javax.servlet.jsp.tagext.JspTag, javax.servlet.jsp.tagext.Tag

public abstract class ChartTag
extends javax.servlet.jsp.tagext.TagSupport

Abstract JSP tag for displaying JFreeChart data in a web page. This class provides the mechanism for displaying any chart, along with an optional image map, with a simple JSP tag. This class is designed to be easily extended, and concrete implementations of this class can define the specific chart displayed through the createChart() method.

The only predefined parameters for the tag are width, height and mapActionUrl. The mapActionUrl parameter defines which web page should be linked to in the image map. If it is omitted, the image map and URL links are not generated. Concrete implementations of this class may add additional parameters for the tag, which can be used in the createChart() method to determine any additional necessary parameters.

This class is currently in the Prajna library. However, it has been submitted to JFreeChart as a contribution. It will be removed from Prajna if JFreeChart adopts it.

Author:

Edward Swing

See Also:

Serialized Form

Field Summary

Fields inherited from class javax.servlet.jsp.tagext.TagSupport

id, pageContext

Fields inherited from interface javax.servlet.jsp.tagext.IterationTag

EVAL_BODY_AGAIN

Fields inherited from interface javax.servlet.jsp.tagext.Tag

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

Constructors

Constructor and Description
ChartTag()

Method Summary

Methods

Modifier and Type	Method and Description
abstract org.jfree.chart.JFreeChart	createChart() Abstract method to create the chart that this tag displays.
int	doStartTag() Generate the HTML code for the tag.
int	getHeight() Get the height of the image
java.lang.String	getMapActionUrl() Get the mapActionUrl.
int	getWidth() Get the width of the image
void	setHeight(int imageHeight) Set the height of the image
void	setMapActionUrl(java.lang.String url) Set the mapActionUrl, which is used to determine the URL links in the resulting image map for the image.
void	setWidth(int imageWidth) Set the width of the image

Methods inherited from class javax.servlet.jsp.tagext.TagSupport

doAfterBody, doEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, release, removeValue, setId, setPageContext, setParent, setValue

Methods inherited from class java.lang.Object

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

Constructor Detail

ChartTag

public ChartTag()

Method Detail

createChart

public abstract org.jfree.chart.JFreeChart createChart()

Abstract method to create the chart that this tag displays. The implementation of this method should include the chart, as well as the optional components such as legend, tooltips, and URL links for the data.

Returns:

the JFreeChart to be displayed within the web page

doStartTag

public int doStartTag()
               throws javax.servlet.jsp.JspException

Generate the HTML code for the tag. This method writes a table element, containing a two-columned table. The first column lists the property names, while the second column displays the values for the property. The table has one row for each property value.

Specified by:

doStartTag in interface javax.servlet.jsp.tagext.Tag

Overrides:

doStartTag in class javax.servlet.jsp.tagext.TagSupport

Returns:

SKIP_BODY

Throws:

javax.servlet.jsp.JspException - if there is a problem writing the tag

getHeight

public int getHeight()

Get the height of the image

Returns:

the image height

getMapActionUrl

public java.lang.String getMapActionUrl()

Get the mapActionUrl. The mapActionUrl is the base URL used to determine the page that any URL links jump to.

Returns:

the mapActionUrl

getWidth

public int getWidth()

Get the width of the image

Returns:

the image width

setHeight

public void setHeight(int imageHeight)

Set the height of the image

Parameters:

imageHeight - the image height

setMapActionUrl

public void setMapActionUrl(java.lang.String url)

Set the mapActionUrl, which is used to determine the URL links in the resulting image map for the image. If this is not set, the image map will not be generated.

Parameters:

url - the mapActionUrl

setWidth

public void setWidth(int imageWidth)

Set the width of the image

Parameters:

imageWidth - the image width