com.google.gwt.user.server.rpc

Class AbstractRemoteServiceServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

Direct Known Subclasses:

RemoteServiceServlet

public abstract class AbstractRemoteServiceServlet
extends javax.servlet.http.HttpServlet

An abstract base class containing utility methods.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.ThreadLocal<javax.servlet.http.HttpServletRequest>	perThreadRequest
protected java.lang.ThreadLocal<javax.servlet.http.HttpServletResponse>	perThreadResponse

Constructor Summary

Constructors

Constructor and Description
AbstractRemoteServiceServlet()

Method Summary

Modifier and Type	Method and Description
void	doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Standard HttpServlet method: handle the POST.
protected void	doUnexpectedFailure(java.lang.Throwable e) Override this method to control what should happen when an exception escapes the doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) method.
protected java.lang.String	getPermutationStrongName() Returns the strong name of the permutation, as reported by the client that issued the request, or null if it could not be determined.
protected javax.servlet.http.HttpServletRequest	getThreadLocalRequest() Gets the HttpServletRequest object for the current call.
protected javax.servlet.http.HttpServletResponse	getThreadLocalResponse() Gets the HttpServletResponse object for the current call.
protected void	onAfterRequestDeserialized(RPCRequest rpcRequest) Override this method to examine the deserialized version of the request before the call to the servlet method is made.
protected abstract void	processPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Called by doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) for type-specific processing of the request.
protected java.lang.String	readContent(javax.servlet.http.HttpServletRequest request) Override this method in order to control the parsing of the incoming request.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

perThreadRequest

protected transient java.lang.ThreadLocal<javax.servlet.http.HttpServletRequest> perThreadRequest

perThreadResponse

protected transient java.lang.ThreadLocal<javax.servlet.http.HttpServletResponse> perThreadResponse

Constructor Detail

AbstractRemoteServiceServlet

public AbstractRemoteServiceServlet()

Method Detail

doPost

public final void doPost(javax.servlet.http.HttpServletRequest request,
                         javax.servlet.http.HttpServletResponse response)

Standard HttpServlet method: handle the POST. Delegates to processPost(HttpServletRequest, HttpServletResponse). This doPost method swallows ALL exceptions, logs them in the ServletContext, and returns a GENERIC_FAILURE_MSG response with status code 500.

Overrides:

doPost in class javax.servlet.http.HttpServlet

doUnexpectedFailure

protected void doUnexpectedFailure(java.lang.Throwable e)

Override this method to control what should happen when an exception escapes the doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) method. The default implementation will log the failure and send a generic failure response to the client.

An "expected failure" is an exception thrown by a service method that is declared in the signature of the service method. These exceptions are serialized back to the client, and are not passed to this method. This method is called only for exceptions or errors that are not part of the service method's signature, or that result from SecurityExceptions, SerializationExceptions, or other failures within the RPC framework.

Note that if the desired behavior is to both send the GENERIC_FAILURE_MSG response AND to rethrow the exception, then this method should first send the GENERIC_FAILURE_MSG response itself (using getThreadLocalResponse), and then rethrow the exception. Rethrowing the exception will cause it to escape into the servlet container.

Parameters:

e - the exception which was thrown

getPermutationStrongName

protected final java.lang.String getPermutationStrongName()

Returns the strong name of the permutation, as reported by the client that issued the request, or null if it could not be determined. This information is encoded in the "X-GWT-Permutation" HTTP header.

getThreadLocalRequest

protected final javax.servlet.http.HttpServletRequest getThreadLocalRequest()

Gets the HttpServletRequest object for the current call. It is stored thread-locally so that simultaneous invocations can have different request objects.

getThreadLocalResponse

protected final javax.servlet.http.HttpServletResponse getThreadLocalResponse()

Gets the HttpServletResponse object for the current call. It is stored thread-locally so that simultaneous invocations can have different response objects.

onAfterRequestDeserialized

protected void onAfterRequestDeserialized(RPCRequest rpcRequest)

Override this method to examine the deserialized version of the request before the call to the servlet method is made. The default implementation does nothing and need not be called by subclasses.

Parameters:

rpcRequest -

processPost

protected abstract void processPost(javax.servlet.http.HttpServletRequest request,
                                    javax.servlet.http.HttpServletResponse response)
                             throws java.lang.Throwable

Called by doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) for type-specific processing of the request. Because doPost swallows all Throwables, this method may throw any exception the implementor wishes.

Throws:

java.lang.Throwable

readContent

protected java.lang.String readContent(javax.servlet.http.HttpServletRequest request)
                                throws javax.servlet.ServletException,
                                       java.io.IOException

Override this method in order to control the parsing of the incoming request. For example, you may want to bypass the check of the Content-Type and character encoding headers in the request, as some proxies re-write the request headers. Note that bypassing these checks may expose the servlet to some cross-site vulnerabilities. Your implementation should comply with the HTTP/1.1 specification, which includes handling both requests which include a Content-Length header and requests utilizing Transfer-Encoding: chuncked.

Parameters:

request - the incoming request

Returns:

the content of the incoming request encoded as a string.

Throws:

javax.servlet.ServletException

java.io.IOException