Class RemoteServiceServlet
The servlet base class for your RPC service implementations that
automatically deserializes incoming requests from the client and serializes
outgoing responses for client/server RPCs.
Constructors
Methods
Constructor Detail
RemoteServiceServlet
public RemoteServiceServlet()
The default constructor.
Method Detail
doGetSerializationPolicy
Gets the
SerializationPolicy for given module base URL and strong
name if there is one.
Override this method to provide a
SerializationPolicy using an
alternative approach.
Parameters
- request
- the HTTP request being serviced
- moduleBaseURL
- as specified in the incoming payload
- strongName
- a strong name that uniquely identifies a serialization
policy file
Return Value
a
SerializationPolicy for the given module base URL and
strong name, or
null if there is none
doPost
public final void doPost(HttpServletRequest request, HttpServletResponse response)
Standard HttpServlet method: handle the POST.
This doPost method swallows ALL exceptions, logs them in the
ServletContext, and returns a GENERIC_FAILURE_MSG response with status code
500.
Parameters
- request
-
- response
-
doUnexpectedFailure
protected void
doUnexpectedFailure(
Throwable e)
Override this method to control what should happen when an exception
escapes the
processCall(String) 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
getSerializationPolicy
Returns a
SerializationPolicy for a given module base URL and
serialization policy strong name.
Parameters
- moduleBaseURL
- the URL for the module
- serializationPolicyStrongName
- strong name of the serialization
policy for the specified module URL
Return Value
a
SerializationPolicy for a given module base URL and RPC
strong name; must not return
null
getThreadLocalRequest
protected final 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 HttpServletResponse getThreadLocalResponse()
Gets the
HttpServletResponse object for the current call. It
is stored thread-locally so that simultaneous invocations can have
different response objects.
onAfterResponseSerialized
protected void
onAfterResponseSerialized(
String serializedResponse)
Override this method to examine the serialized response that will be
returned to the client. The default implementation does nothing and need
not be called by subclasses.
Parameters
- serializedResponse
-
onBeforeRequestDeserialized
protected void
onBeforeRequestDeserialized(
String serializedRequest)
Override this method to examine the serialized version of the request
payload before it is deserialized into objects. The default implementation
does nothing and need not be called by subclasses.
Parameters
- serializedRequest
-
processCall
Process a call originating from the given request. Uses the
Method, Object[])
method to do the actual work.
Subclasses may optionally override this method to handle the payload in any
way they desire (by routing the request to a framework component, for
instance). The HttpServletRequest and HttpServletResponse
can be accessed via the getThreadLocalRequest() and
getThreadLocalResponse() methods.
This is public so that it can be unit tested easily without HTTP.
Parameters
- payload
- the UTF-8 request payload
Return Value
a string which encodes either the method's return, a checked
exception thrown by the method, or an
IncompatibleRemoteServiceException
shouldCompressResponse
protected boolean
shouldCompressResponse(
HttpServletRequest request, HttpServletResponse response, String responsePayload)
Determines whether the response to a given servlet request should or should
not be GZIP compressed. This method is only called in cases where the
requestor accepts GZIP encoding.
This implementation currently returns true if the response
string's estimated byte length is longer than 256 bytes. Subclasses can
override this logic.
Parameters
- request
- the request being served
- response
- the response that will be written into
- responsePayload
- the payload that is about to be sent to the client
Return Value
true if responsePayload should be GZIP compressed,
otherwise
false.
