nu.staldal.lsp.framework
Class ThrowawayService

java.lang.Object
  nu.staldal.lsp.framework.ThrowawayService

Direct Known Subclasses:

EasyService

public abstract class ThrowawayService
extends java.lang.Object

Abstract base class for Throwaway Service.

Services will be loaded and instantiated using Class.forName and Class.newInstance, so they must have a public no-arg constructor.

A new instance will be created for each request, and that instance is thrown away after the request. The execute method is only invoked once per instance, so there are no thread-safety issues. It's not a problem to use instance fields.

Use the Parameter annotation on instance fields to automatically populate them with HTTP request parameter values.

Field Summary

protected javax.servlet.ServletContext	context The ServletContext.
protected DBConnection	dbConn database connection to use for this request, or null if no database has been setup
protected java.util.List<java.lang.String>	extraArgs Any extra URL path components from RestfulDispatcherServlet, or null if another dispatcher is used.
static java.lang.String	INCLUDE_ATTR_PREFIX Prefix for request attributes for include attributes.
protected javax.sql.DataSource	mainDB The DataSource to main database, or null if no database is setup.
protected javax.servlet.http.HttpServletRequest	request The HttpServletRequest.
static int	REQUEST_DELETE Request type DELETE.
static int	REQUEST_GET Request type GET.
static int	REQUEST_INCLUDE Request type include.
static int	REQUEST_POST Request type POST.
static int	REQUEST_PUT Request type PUT.
protected int	requestType The request type.
protected javax.servlet.http.HttpServletResponse	response The HttpServletResponse.

Constructor Summary

ThrowawayService()

Method Summary

abstract java.lang.String	execute(java.util.Map<java.lang.String,java.lang.Object> pageParams) Invoked for a request to this Service.
protected java.util.Locale	getUserLocale() Get the user's locale.

Methods inherited from class java.lang.Object

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

Field Detail

REQUEST_GET

public static final int REQUEST_GET

Request type GET.

See Also:

Constant Field Values

REQUEST_POST

public static final int REQUEST_POST

Request type POST.

See Also:

Constant Field Values

REQUEST_INCLUDE

public static final int REQUEST_INCLUDE

Request type include.

See Also:

Constant Field Values

REQUEST_PUT

public static final int REQUEST_PUT

Request type PUT.

See Also:

Constant Field Values

REQUEST_DELETE

public static final int REQUEST_DELETE

Request type DELETE.

See Also:

Constant Field Values

INCLUDE_ATTR_PREFIX

public static final java.lang.String INCLUDE_ATTR_PREFIX

Prefix for request attributes for include attributes.

See Also:

Constant Field Values

context

protected javax.servlet.ServletContext context

The ServletContext.

request

protected javax.servlet.http.HttpServletRequest request

The HttpServletRequest.

response

protected javax.servlet.http.HttpServletResponse response

The HttpServletResponse.

mainDB

protected javax.sql.DataSource mainDB

The DataSource to main database, or null if no database is setup.

dbConn

protected DBConnection dbConn

database connection to use for this request, or null if no database has been setup

requestType

protected int requestType

The request type. REQUEST_GET, REQUEST_POST, REQUEST_PUT, REQUEST_DELETE or REQUEST_INCLUDE

extraArgs

protected java.util.List<java.lang.String> extraArgs

Any extra URL path components from RestfulDispatcherServlet, or null if another dispatcher is used.

Constructor Detail

ThrowawayService

public ThrowawayService()

Method Detail

getUserLocale

protected java.util.Locale getUserLocale()

Get the user's locale.

Returns:

the user's locale, never null

execute

public abstract java.lang.String execute(java.util.Map<java.lang.String,java.lang.Object> pageParams)
                                  throws java.lang.Exception

Invoked for a request to this Service.

Is invoked for GET, HEAD, POST, PUT and DELETE requests. You should not treat HEAD requests differently than GET requests, the framework will automatically discard the body and only send the headers. The requestType field indicate the type of request. See the HTTP specification for differences between GET and POST requests.

There are three choices to create the response:

1. Return the name of a page to display, and fill pageParams with parameters to this page. In this case, response should only be used to set headers.
2. Send the whole response by using response and return null. In this case the framework will not touch response after this method returns, and will not use pageParams. This can be used if you want to use sendError or sendRedirect.
3. Return the name of an other service to forward the request to, prefixed by "*". Any parameters added to pageParams are retained. You may add attributes to request in order to comnunicate with the other service.

If requestType is REQUEST_INCLUDE, choice 2 and 3 may not be used, and response may not be modified in any way. You may either return the name of page, or use the SAX2 ContentHandler passed as a request attribute with name "org.xml.sax.ContentHandler" and return null. startDocument and endDocument must not be invoked on the ContentHandler, use ContentHandlerStartEndDocumentFilter if this is a problem.

Parameters:

pageParams - map for page parameters

Returns:

name of the page to view, or null to not use any page, or the name of an other service to forward to prefixed by "*"

Throws:

java.lang.Exception - may throw any Exception