examples.news
Class NewsFormatter

java.lang.Object
  examples.news.NewsFormatter

All Implemented Interfaces:

ResponseFormatter

public class NewsFormatter
extends Object
implements ResponseFormatter

This is a simple example of how you can implement your own ResponseFormatter to suit your own needs. This class implements the ResponseFormatter interface and requires an extra URL parameter called 'wires'. It has a predefined set of possible values for wires and a default should the user specify an unrecognised wire.
The possible values for wires are:

• Energy
• Commodities
• World
• World
• Europe

Each type of wire has its own response. The response is comprised of a user name and a message about the current news.

Author:

David Shorten

Field Summary

static String	DEFAULT_WIRE_TYPE Specifies the default value of 'wires' if the one supplied was invalid.
static String[]	POSSIBLE_WIRE_TYPES Specifies the different types of 'wires' that are valid.
static String[]	POSSIBLE_WIRE_VALUES Specifies the relevant response to each valid value for 'wires'.

Constructor Summary

NewsFormatter()

Method Summary

String	formatErrorResponse(javax.servlet.http.HttpServletRequest request, String errorMessage) This method records in the log than an error response is being returned and what the error was.
String	formatResponse(javax.servlet.http.HttpServletRequest request, String token) Implementation of the interface method.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WIRE_TYPE

public static final String DEFAULT_WIRE_TYPE

Specifies the default value of 'wires' if the one supplied was invalid.

See Also:

Constant Field Values

POSSIBLE_WIRE_TYPES

public static final String[] POSSIBLE_WIRE_TYPES

Specifies the different types of 'wires' that are valid.

POSSIBLE_WIRE_VALUES

public static final String[] POSSIBLE_WIRE_VALUES

Specifies the relevant response to each valid value for 'wires'.

Constructor Detail

NewsFormatter

public NewsFormatter()

Method Detail

formatResponse

public String formatResponse(javax.servlet.http.HttpServletRequest request,
                             String token)

Implementation of the interface method. The method initialises a Map to hold all the different types of wire and each corresponding message. This allows quick retrieval of the message as the parameter is used as the key. if the key ("wires") returns null then the default message is returned, otherwise the corresponding message is returned.

Specified by:

formatResponse in interface ResponseFormatter

Parameters:

request - the HttpServletRequest object that contains the URL and parameters etc.

token - the generated token for this request.

Returns:

a string containing a message and the token or an error message.

formatErrorResponse

public String formatErrorResponse(javax.servlet.http.HttpServletRequest request,
                                  String errorMessage)

This method records in the log than an error response is being returned and what the error was. It then returns the errorMessage.

Specified by:

formatErrorResponse in interface ResponseFormatter

Parameters:

request - A request object that was used to call the calling servlet.

errorMessage - A description of what has gone wrong.

Returns:

the error message that has been passed in.