netcharts.pro.util
Class NFServletUtil

java.lang.Object
  |
  +--netcharts.pro.util.NFServletUtil

public class NFServletUtil

extends java.lang.Object

NFServletUtil provides methods to make server side generation of chart images and images maps easier. In order to explain the process, first we will explain the terminology:

An image, as we use it here, is essentially a picture of a chart in time. The picture is encoding into bytes using a particular mime type. (by default "image/png").

An image map is what gives the image dynamic behavior. It identifies regions of the chart image that support rollover popup messages or "drilldown" hyperlink behavior. In addition to these "regions", the image map contains a URL for the image itself.

Image and image map generation occurs in two stages. In the first stage, the image is generated along with the image map. The servlet then returns just the image map. The browser then parses the image map and requests the image using the URL in the image map.

Finally, please note that the methods in this class are intended to simplify the image/image map features that NetCharts Pro provides. A great deal of flexibility is available by explicitly managing the process using the methods in the NFImageGeneration class.

Field Summary

static java.lang.String	ACCESSIBLE_PAGE The location of the default accessibility enhanced template.
static java.lang.String	DEFAULT_ALT_TEMPLATE The default template to use in the alt attribute for accessibility enhanced pages.
static java.lang.String	DEFAULT_MIME_TYPE The default MIME type used when generating image.
static java.lang.String	DEFAULT_URL The default URL for active labels.
static java.lang.String	DRILLDOWN_PAGE The location of the default drilldown template.
static java.lang.String	IMAGE_PARAMETER The parameter appended to img elements identifying the HTTP session variable used to hold the binary image data.
static java.lang.String	MIME_TYPE_BMP image/bmp
static java.lang.String	MIME_TYPE_JPG image/jpg
static java.lang.String	MIME_TYPE_PICT image/pict
static java.lang.String	MIME_TYPE_PNG image/png
static java.lang.String	MIME_TYPE_TGA image/tga
static java.lang.String	MIME_TYPE_TIFF image/tiff
static java.lang.String	MIME_TYPE_WBMP image/wbmp
static java.lang.String	MIME_TYPE_XBM image/xbm
static java.lang.String	MIME_TYPE_XPM image/xpm
static java.lang.String	MIN_DRILLDOWN_PAGE The location of the default minimum drilldown template.

Constructor Summary

NFServletUtil()

Method Summary

static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, boolean fullPage) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, boolean fullPage, java.lang.String servletName) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, boolean fullPage, java.lang.String servletName, boolean accessible, java.lang.String altTemplate, java.lang.String chartDescription) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, boolean fullPage, java.lang.String servletName, boolean accessible, java.lang.String altTemplate, java.lang.String chartDescription, java.lang.String defaultHref) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, boolean fullPage, java.lang.String servletName, java.lang.String defaultHref) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getDrillDownPage(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, java.lang.String defaultHref) Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.
static java.lang.String	getImageSrcTag(NFGraph chart, netcharts.pro.util.HttpServletRequest request) Generates an image from the given chart and returns an HTML image src tag that provides a reference to the page.
static java.lang.String	getImageSrcTag(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType) Generates an image from the given chart and returns an HTML image src tag that provides a reference to the page.
static java.lang.String	getImageSrcTag(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, boolean accessible, java.lang.String chartDescription) Generates an image from the given chart and returns an HTML image src tag that provides a reference to the page.
static java.lang.String	getImageSrcTag(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, java.lang.String servletName) Generates an image from the given chart and returns an HTML image src tag that provides a reference to the servlet specified.
static java.lang.String	getImageSrcTag(NFGraph chart, netcharts.pro.util.HttpServletRequest request, java.lang.String mimeType, java.lang.String servletName, boolean accessible, java.lang.String chartDescription) Generates an image from the given chart and returns an HTML image src tag that provides a reference to the servlet specified.
static java.lang.String	getRolloverJavaScript() Return the JavaScript and <div> tag used for chart interactivity.
static boolean	isSecondPass(netcharts.pro.util.HttpServletRequest request) Determines if this is the second pass, or image retrieval call, to this servlet.
static boolean	writeImage(netcharts.pro.util.HttpServletRequest request, netcharts.pro.util.HttpServletResponse response) Retrieves the image from the session and writes it to the response output stream.

Methods inherited from class java.lang.Object

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

Field Detail

IMAGE_PARAMETER

public static final java.lang.String IMAGE_PARAMETER

The parameter appended to img elements identifying the HTTP session variable used to hold the binary image data.

DRILLDOWN_PAGE

public static final java.lang.String DRILLDOWN_PAGE

The location of the default drilldown template.

MIN_DRILLDOWN_PAGE

public static final java.lang.String MIN_DRILLDOWN_PAGE

The location of the default minimum drilldown template.

ACCESSIBLE_PAGE

public static final java.lang.String ACCESSIBLE_PAGE

The location of the default accessibility enhanced template.

DEFAULT_ALT_TEMPLATE

public static final java.lang.String DEFAULT_ALT_TEMPLATE

The default template to use in the alt attribute for accessibility enhanced pages.

DEFAULT_URL

public static final java.lang.String DEFAULT_URL

The default URL for active labels.

MIME_TYPE_PNG

public static final java.lang.String MIME_TYPE_PNG

image/png

MIME_TYPE_TIFF

public static final java.lang.String MIME_TYPE_TIFF

image/tiff

MIME_TYPE_JPG

public static final java.lang.String MIME_TYPE_JPG

image/jpg

MIME_TYPE_BMP

public static final java.lang.String MIME_TYPE_BMP

image/bmp

MIME_TYPE_TGA

public static final java.lang.String MIME_TYPE_TGA

image/tga

MIME_TYPE_XPM

public static final java.lang.String MIME_TYPE_XPM

image/xpm

MIME_TYPE_XBM

public static final java.lang.String MIME_TYPE_XBM

image/xbm

MIME_TYPE_PICT

public static final java.lang.String MIME_TYPE_PICT

image/pict

MIME_TYPE_WBMP

public static final java.lang.String MIME_TYPE_WBMP

image/wbmp

DEFAULT_MIME_TYPE

public static final java.lang.String DEFAULT_MIME_TYPE

The default MIME type used when generating image. Equal to MIME_TYPE_PNG.

Constructor Detail

NFServletUtil

public NFServletUtil()

Method Detail

getRolloverJavaScript

public static java.lang.String getRolloverJavaScript()

Return the JavaScript and <div> tag used for chart interactivity. This can be used to introduce the script code at any time during the page creation process. Commonly used when the final resultant page contains charts within tables.

Returns:

The JavaScript and <div> tag used for interactivity.

isSecondPass

public static boolean isSecondPass(netcharts.pro.util.HttpServletRequest request)

Determines if this is the second pass, or image retrieval call, to this servlet.

Parameters:

request - The servlet request. If this is the second pass, the servlet request will have a image ID set as a session variable.

Returns:

true if this is the second call.

writeImage

public static boolean writeImage(netcharts.pro.util.HttpServletRequest request,
                                 netcharts.pro.util.HttpServletResponse response)

Retrieves the image from the session and writes it to the response output stream.

Parameters:

request - The servlet request. This is expected to contain the unique image ID generated during the call to "getDrillDownPage()"

response - The output

Returns:

true if the image was written, false if not.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType,
                                                java.lang.String defaultHref)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

defaultHref - Href to use if one isn't defined for the area tag.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType,
                                                boolean fullPage)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

fullPage - Whether the full script should be included within the return.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType,
                                                boolean fullPage,
                                                java.lang.String servletName)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

fullPage - Whether the full script should be included within the return.

servletName - The name of the servlet to put into the image map to retrieve the image.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType,
                                                boolean fullPage,
                                                java.lang.String servletName,
                                                java.lang.String defaultHref)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

fullPage - Whether the full script should be included within the return.

servletName - The name of the servlet to put into the image map to retrieve the image.

defaultHref - Href to use if one isn't defined for the area tag.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType,
                                                boolean fullPage,
                                                java.lang.String servletName,
                                                boolean accessible,
                                                java.lang.String altTemplate,
                                                java.lang.String chartDescription)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

fullPage - Whether the full script should be included within the return.

servletName - The name of the servlet to put into the image map to retrieve the image.

accessible - Whether accessibility features (like alt tags) should be used in the drill down page instead of javascript based popup labels

altTemplate - The text template used to construct alt tags on the active regions of a drill down image (map area tags).

chartDescription - The description to be used in the alt tag on chart images.

Returns:

HTML image map or error message if template image map cannot be found.

getDrillDownPage

public static java.lang.String getDrillDownPage(NFGraph chart,
                                                netcharts.pro.util.HttpServletRequest request,
                                                java.lang.String mimeType,
                                                boolean fullPage,
                                                java.lang.String servletName,
                                                boolean accessible,
                                                java.lang.String altTemplate,
                                                java.lang.String chartDescription,
                                                java.lang.String defaultHref)
                                         throws java.lang.Exception

Generates an image from the given chart and returns an HTML image map that provides a reference to the page as well as javascript code to manage rollover and drilldown behavior.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

fullPage - Whether the full script should be included within the return.

servletName - The name of the servlet to put into the image map to retrieve the image.

accessible - Whether accessibility features (like alt tags) should be used in the drill down page instead of javascript based popup labels

altTemplate - The text template used to construct alt tags on the active regions of a drill down image (map area tags).

chartDescription - The description to be used in the alt tag on chart images.

defaultHref - Href to use if one isn't defined for the area tag.

Returns:

HTML image map or error message if template image map cannot be found.

getImageSrcTag

public static java.lang.String getImageSrcTag(NFGraph chart,
                                              netcharts.pro.util.HttpServletRequest request)
                                       throws java.lang.Exception

Generates an image from the given chart and returns an HTML image src tag that provides a reference to the page.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

Returns:

HTML image src tag or error message if template image map cannot be found.

getImageSrcTag

public static java.lang.String getImageSrcTag(NFGraph chart,
                                              netcharts.pro.util.HttpServletRequest request,
                                              java.lang.String mimeType)
                                       throws java.lang.Exception

Generates an image from the given chart and returns an HTML image src tag that provides a reference to the page.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

Returns:

HTML image src tag or error message if template image map cannot be found.

getImageSrcTag

public static java.lang.String getImageSrcTag(NFGraph chart,
                                              netcharts.pro.util.HttpServletRequest request,
                                              java.lang.String mimeType,
                                              java.lang.String servletName)
                                       throws java.lang.Exception

Generates an image from the given chart and returns an HTML image src tag that provides a reference to the servlet specified.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

servletName - The name of the servlet to put into the image map to retrieve the image.

Returns:

HTML image src tag or error message if template image map cannot be found.

getImageSrcTag

public static java.lang.String getImageSrcTag(NFGraph chart,
                                              netcharts.pro.util.HttpServletRequest request,
                                              java.lang.String mimeType,
                                              boolean accessible,
                                              java.lang.String chartDescription)
                                       throws java.lang.Exception

Generates an image from the given chart and returns an HTML image src tag that provides a reference to the page.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

accessible - Whether accessibility features (like alt tags) should be used in the drill down page instead of javascript based popup labels

chartDescription - The description to be used in the alt tag on chart images.

Returns:

HTML image src tag or error message if template image map cannot be found.

getImageSrcTag

public static java.lang.String getImageSrcTag(NFGraph chart,
                                              netcharts.pro.util.HttpServletRequest request,
                                              java.lang.String mimeType,
                                              java.lang.String servletName,
                                              boolean accessible,
                                              java.lang.String chartDescription)
                                       throws java.lang.Exception

Generates an image from the given chart and returns an HTML image src tag that provides a reference to the servlet specified.

Parameters:

chart - The chart object to create the image and image map for.

request - The servlet request. Session information about the image will be written here.

mimeType - The image MIME type of the image to produce.

servletName - The name of the servlet to put into the image map to retrieve the image.

accessible - Whether accessibility features (like alt tags) should be used in the drill down page instead of javascript based popup labels

chartDescription - The description to be used in the alt tag on chart images.

Returns:

HTML image src tag or error message if template image map cannot be found.