org.faceless.report
Class PDFFilter

java.lang.Object
  org.faceless.report.PDFFilter

All Implemented Interfaces:

Filter, ErrorHandler

public class PDFFilter
extends Object
implements Filter, ErrorHandler

The PDFFilter class is an implementation of the Servlet 2.3 Filter interface, which automatically converts an XML report into a PDF which is returned to the client. For those still using the Servlet 2.2 architecture, The PDFProxyServlet does a similar job.

More information on installing filters is available in the Servlet Specification and has probably been supplied with your Servlet engine. For the impatient, here's an example setup which would cause all requests to anything in the /pdf/ path of your website to be converted to a PDF. Add the following lines to your WEB-INF/web.xml file:

    <filter>
      <filter-name>bforeport</filter-name>
      <filter-class>org.faceless.report.PDFFilter</filter-class>
    </filter>
    <filter-mapping>
      <filter-name>bforeport</filter-name>
      <url-pattern>/pdf/*</url-pattern>
    </filter-mapping>
 

Meta tags that aren't already known to the Report Generator and that begin with "HTTP-" are added to the response header (minus the "HTTP-" prefix). An example would be to place <meta name="HTTP-Expires" value="Mon, 01 Jan 1999 12:00:00 GMT"> in the head of the XML, which would set the "Expires" header in the HTTP response.

The following custom Meta-Tags may also be used to control the behaviour of the servlet.

• Servlet-Filename - ask the client browser to save the file as the specified filename instead of displaying it inline. This uses the Content-Disposition header, which in theory is accepted by NS4+ and IE5+, although this known bug in IE5.5 may prevent the document from being viewed at all. Use with caution unless you know your audiences browsers.

• org.xml.sax.driver - may be set to the base class of your SAX parsers XMLReader implementation, if the generator is unable to locate it.
• org.faceless.report.flag.WarningUnknownTag - may be set to true or false to generate warnings about unknown tags. Default is "true"
• org.faceless.report.flag.WarningUnknownAttribute - may be set to true or false to generate warnings about unknown attributes. Default is "true"
• org.faceless.report.flag.WarningMisplacedText - may be set to true or false to generate warnings about misplaced text. Default is "true"
• cache-minsize and cache-prefix - can be set to cache parts of the created document to disk.

These last two parameters were added in version 1.1.19 to cause parts of the document to be cached to disk. This can reduce memory footprint slightly, although it may slow things down a little so you must decide whether it's appropriate or not. The cache-prefix and cache-minsize parameters are passed into the DiskCache constructor - essentially the prefix should be a temporary directory, optionally with the first half of a filename. The minsize parameter sets the minimum size a stream may be before it's considered to be worth caching to disk. For example, to store streams greater than 8k in the "/tmp/cache" directory and call them "bfo.1", "bfo.2" and so on, you could do something like this:

    <filter>
      <filter-name>bforeport</filter-name>
      <filter-class>org.faceless.report.PDFFilter</filter-class>
      <init-param>
        <param-name>cache-minsize</param-name>
        <param-value>8192</param-value>
      </init-param>
      <init-param>
        <param-name>cache-prefix</param-name>
        <param-value>/tmp/cache/bfo.</param-value>
      </init-param>
    </filter>
 

This class also implements org.xml.sax.ErrorHandler, to deal with any errors found during the XML parsing process. Currently all warnings and errors are fatal, and logged to System.err.

PDFFilter

public PDFFilter()

init

public void init(FilterConfig config)
          throws ServletException

Specified by:

init in interface Filter

Throws:

ServletException

destroy

public void destroy()

Specified by:

destroy in interface Filter

getFilterConfig

public FilterConfig getFilterConfig()

Return the Filter Config. A non-standard method required for WebLogic 6.1

setFilterConfig

public void setFilterConfig(FilterConfig conf)

Set the Filter Config. A non-standard method required for WebLogic 6.1

doFilter

public void doFilter(ServletRequest request,
                     ServletResponse response,
                     FilterChain chain)
              throws ServletException,
                     IOException

Specified by:

doFilter in interface Filter

Throws:

ServletException

IOException

metaTag

public void metaTag(HttpServletRequest reader,
                    HttpServletResponse writer,
                    String name,
                    String value)
             throws ServletException,
                    IOException

Handle any meta tags that aren't recognised by the core Report Generator. This method recognises tags begining with HTTP-, as well as Servlet-FileName.

Parameters:

request - the Servlet request

response - the Servlet request

name - the "name" attribute from the meta tag

value - the "value" attribute from the meta tag

Throws:

ServletException

IOException

warning

public void warning(SAXParseException exception)
             throws SAXException

Specified by:

warning in interface ErrorHandler

Throws:

SAXException

error

public void error(SAXParseException exception)
           throws SAXException

Specified by:

error in interface ErrorHandler

Throws:

SAXException

fatalError

public void fatalError(SAXParseException exception)
                throws SAXException

Specified by:

fatalError in interface ErrorHandler

Throws:

SAXException