com.ibm.wbi.protocol.http.beans
Class ErrorPageGenerator

com.ibm.wbi.Meg
  |
  +--com.ibm.wbi.Generator
        |
        +--com.ibm.wbi.protocol.http.HttpGenerator
              |
              +--com.ibm.wbi.protocol.http.beans.FourStepHttpGenerator
                    |
                    +--com.ibm.wbi.protocol.http.beans.ErrorPageGenerator

public class ErrorPageGenerator

extends FourStepHttpGenerator

A Generator for producing an HTTP response that corresponds to an error condition. It is designed to work in conjunction with the ErrorPageException class. Typically, the programmer will write a Generator with a try block around code where an error condition could occur. When the error is detected, an ErrorPageException object should be constructed and thrown. The catch block would then construct an ErrorPageGenerator from the ErrorPageException and forward the original RequestEvent to it for handling. The ErrorPageGenerator will then produce the appropriate response.

For example:

  public void handleRequest(RequestEvent e) {
    try {
      ... determine if error has occurred ...
      if (error) throw new ErrorPageException(404, "URL does not exist");
      .. do other stuff ...
    } catch (ErrorPageException epe) {
      forwardRequest(new ErrorPageGenerator(epe), e);
    }
  }
  

There are three properties that can be set: ResponseCode, ResponseText, and PageText. The ResponseCode is the HTTP code that will be in the HTTP response. The ResponseText is the short message that is part of the HTTP response. The PageText is the HTML that accompanies the HTTP response.

See Also:

ErrorPageException

Field Summary

static java.lang.String	COPYRIGHT IBM copyright information
protected java.lang.String	pageText The page text.

Fields inherited from class com.ibm.wbi.protocol.http.HttpGenerator

http

Fields inherited from class com.ibm.wbi.Meg

EDITOR, GENERATOR, MONITOR, REQUEST_EDITOR, UNDEFINED

Constructor Summary

ErrorPageGenerator()
Construct an instance with a ResponseCode of 400, a ResponseText of "Unknown Error", and a PageText of "".

ErrorPageGenerator(ErrorPageException e)
Construct an instance from the information in the ErrorPageException.

Method Summary

protected java.lang.String	getHeader(RequestEvent e) Get the header.
java.lang.String	getPageText() Access the PageText property.
int	getResponseCode() Access the ResponseCode property.
java.lang.String	getResponseText() Access the ResponseText property.
void	setPageText(java.lang.String pt) Set the PageText property.
void	setResponseCode(int rc) Set the ResponseCode property.
void	setResponseText(java.lang.String rt) Set the ResponseText property.
protected void	writeContent(RequestEvent e) Write the content to the output stream.

Methods inherited from class com.ibm.wbi.protocol.http.beans.FourStepHttpGenerator

handleRequest, initialize, verify

Methods inherited from class com.ibm.wbi.protocol.http.HttpGenerator

add, addCookie, getContentType, getHttpResponse, getHttpResponseString, isCache, produceHeader, set, setCache, setContentLength, setContentType, setServer, writeHeader

Methods inherited from class com.ibm.wbi.Generator

getType

Methods inherited from class com.ibm.wbi.Meg

forwardRequest, getCondition, getEnabled, getMegProperty, getMegProperty, getMegPropertyKeys, getName, getPlugin, getPriority, getSystemContext, initialize, initialize, isEnabled, isMegApplicable, loadMegResources, run, setCondition, setEnabled, setMegProperty, setName, setPriority, setSystemContext, setup, setup, setup, setup

Field Detail

COPYRIGHT

public static final java.lang.String COPYRIGHT

IBM copyright information

pageText

protected java.lang.String pageText

The page text.

Constructor Detail

ErrorPageGenerator

public ErrorPageGenerator()

Construct an instance with a ResponseCode of 400, a ResponseText of "Unknown Error", and a PageText of "".

ErrorPageGenerator

public ErrorPageGenerator(ErrorPageException e)

Construct an instance from the information in the ErrorPageException.

Parameters:

e - The exception which indicates the type and cause of the error.

Method Detail

setPageText

public void setPageText(java.lang.String pt)

Set the PageText property.

Parameters:

pt - The HTML that will be passed back to the browser for display.

getPageText

public java.lang.String getPageText()

Access the PageText property.

setResponseCode

public void setResponseCode(int rc)

Set the ResponseCode property.

Overrides:

setResponseCode in class HttpGenerator

Parameters:

rc - The HTTP response code that will be passed back to the browser (e.g. 200, meaning "Ok").

getResponseCode

public int getResponseCode()

Access the ResponseCode property.

Overrides:

getResponseCode in class HttpGenerator

Returns:

The ResponseCode

setResponseText

public void setResponseText(java.lang.String rt)

Set the ResponseText property.

Overrides:

setResponseText in class HttpGenerator

Parameters:

rt - The response text that accompanies the HTTP response (e.g. "Ok").

getResponseText

public java.lang.String getResponseText()

Access the ResponseText property.

Overrides:

getResponseText in class HttpGenerator

Returns:

The ResponseText

getHeader

protected java.lang.String getHeader(RequestEvent e)

Get the header.

Overrides:

getHeader in class FourStepHttpGenerator

Parameters:

e - The request event,

Returns:

The header.

writeContent

protected void writeContent(RequestEvent e)
                     throws java.io.IOException

Write the content to the output stream.

Overrides:

writeContent in class FourStepHttpGenerator

Parameters:

e - The request event.

Throws:

java.io.IOException - If an error occurs.