Cewolf / News: Recent posts

This upgrade release of the taglibrary for charts comes with some improvements regarding the server side caching:
- useful image caching with cleanup mechanisms to avoid running out of memory
- bugfix in image key computing
- faster caching and key generation
- init parameters for cewolf servlet to manipulate caching (see example etc/web.xml)

The newest release has been mainly developed to make Cewolf runnable in Macromedia's JRun server.
As the include directive has a serious bug in JRun 4 (see http://webforums.macromedia.com/jrun/messageview.cfm?catid=254&threadid=452782\) the web application runs only on JRun 4.SP1 beta.

Regards,
Guido

Cewolf stands for "Chart Enabling Web Objects Framework". It can be used to easily embed charts of all kinds into a Servlet/JSP based web application. After a development period of more than one month and a testing phase of 3 weeks the next generation of Cewolf is released at least.

The new version comes with many improvements:
ChartPostProcessor process method signature now has a third parameter with the
current dataset of the rendered chart to enhance capabilities of processing
- tag does not render a image anymore. is only used to define
a chart instance initially inside a JSP. The rendering of the chart image is
performed by the tag which is passed the chart id as an attribute.
- image maps and tooltips implemented (tested on IE 5.5 and Mozilla 1.1)
- added tag which can be used as the src attribute of an HTML img tag
- obsolete tag has been removed all attributes can be set directly to
the tag now
- server side caching of images to gain performance blast when requesting the same
chart again
- many redesigns
- polished example webapp
- fixed a bug which prevented reloading of a page
- fixed a bug which let the tag produce same keys for different charts whan tags
are pooled... read more

Hi,

there will be a lot of changes in the 0.8 of Cewolf.
I implemented a server side image cache which will be configurable in memory size and expiration time of single chart instances. Future versions will also be able to cache the images as blob in a database.
Unfortunalety the cache implementation causes a lot of redesigns whcih will definitly affect alreayd productive Cewolf systems.
The chart definition is now separated from the image rendering. So the cewolf:chart tag does NOT add the image tag to the rendered HTML page anymore. Therfore a cewolf:img tag has been introduced which does the job.
The implementation of an image map which was called for severeal times will be included in the 0.8 as well.
The 0.8 will hopefully go beta in the end of the week and final end of the next week.
Stay tuned,
Guido

This is an important update as it fixes a fundamental bug. On browsers with disabled cookies a chart rendering was not possible before.
This could also fix the well-known "no image/no error" problem which has been posted for several times.

Regards,
Guido

Quite a long alpha and beta phase, but now it is done.
Cewolf 0.7 comes with some really new features which should give users many new customization opprtunities.

Change log:
- unlimited customization of generated charts possible through additional ChartPostProcessor objects. See <chartpostprocessor> documentation!
- changed signature of DatasetProducer. Params are now passed as Map instead HashMap
- new <legend> tag to render the chart's legend separately
- added "legend" and "legendanchor" attribute to panel and chart tag to swith on/off and manipulate legend display
- new tag <legend> allows the separate rendering of the chart's legend somewhere in the JSP
- <chart> and <legend> tag now support all HTML 4.0 img tag attributes
- rendering servlet now renders an exception into the delivered image if one is raised when trying to render the chart
- removed obsolete example page producerparams.jsp (view testpage.jsp instead)
- the example.war binary is now distributed separately
- example web.xml no has an url-mapping to work in more J2EE containers
- better usage of JSP callbacks by overriding the release() method in tags
- enhanced test page for JSP 1.1 and JSP 1.2 containers
- enhanced image loading performance
- redesigned, optimized and simplified some issues
- some javadocs... read more

This is the next bug patch release which patches an error in testpage.jsp and testpage-1.1 (twice closing tag)

Notes:
This is a patch release which fixes an error in the TLD of 0.6.
It does not contain the examlpe .war file. If you want to build the example war:
1. put servlet.jar, jaxp.jar into /lib
2. run ant target war.

Changes:
- fixed a bug in the tag library descriptor which defined the background attribute of tag chart as a float instead of String

- added tags <color-paint>, <gradient-paint> and <texture-paint>
for background paints of chart panel
- some refactorings in tag lib implementation
- testpage enhanced
- added a JSP 1.1 compliant tag lib descriptor

This is only a bugfix release which is needed if you want to use the "background" attribute of tag "chart".

This is a bug fix release which should solve reported errors on some servlet environments when trying to reuse a formally instantitated chart tag handler.
You should use this instead of 0.5.

This is the first fully documented release of Cewolf. It includes a full specification of all provided tags and some examples.

Release notes:
- the data tag now embeds a producer tag, future releases will have other possibilities to provide data (e.g. SQL)
- added support for Pie3DChart
- added <panel> tag to be embedded in <chart> tag
- embedded <panel> tag attributes override coressponing parent tags attributes
- <chart> tag now extends <panel> tag
- changed value type of <param> tag to java.io.Serilizable
- added antialias support
- added tag library documentation
- added some javadocs
- added some example JSPs... read more

Version 0.4 of Cewolf has been released today.
It has some improvements of how to provide a DatasetProducer. It is now possible to pass arguments to the producer from the JSP.

After some redesigned and a new compilation time check for chart type conformity version 0.3 has been released.
Have Fun
Guido