org.apache.jdo.impl.fostore
Class CreateOIDHandler

java.lang.Object
  extended byorg.apache.jdo.impl.fostore.RequestHandler
      extended byorg.apache.jdo.impl.fostore.CreateOIDHandler

class CreateOIDHandler
extends RequestHandler

Process CreateOIDRequests. Causes allocation of a new OID in the datastore.

Author:
Dave Bristor

Nested Class Summary
(package private) static interface RequestHandler.HandlerFactory
          Means by which subclasses are created.
 
Field Summary
protected  FOStoreServerConnection con
          Connection on which the Request arrived.
static RequestHandler.HandlerFactory factory
           
protected  int length
          Length of the data in the Request.
(package private) static org.apache.commons.logging.Log logger
          Logger
protected  Reply reply
          Subclasses use this Reply instance to send data back to their corresponding client-side request.
 
Constructor Summary
private CreateOIDHandler(Reply reply, int length, FOStoreServerConnection con)
           
 
Method Summary
protected  boolean getOkToFinish()
          The RollbackHandler should override this and return false, so that finishers are not run when we are rolling back.
(package private)  RequestFinisher handleRequest()
          Subclasses implement this to take care of individiual requests.
(package private) static void handleRequests(FOStoreServerConnection con)
          Handles all requests that can be read at this time from the given connection.
protected  void setOkToCommit(boolean okToCommit)
          The CommitHandler should override this and save the given value, then use it to determine whether or not to commit.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

factory

public static final RequestHandler.HandlerFactory factory

reply

protected final Reply reply
Subclasses use this Reply instance to send data back to their corresponding client-side request.


length

protected final int length
Length of the data in the Request.


con

protected final FOStoreServerConnection con
Connection on which the Request arrived.


logger

static final org.apache.commons.logging.Log logger
Logger

Constructor Detail

CreateOIDHandler

private CreateOIDHandler(Reply reply,
                         int length,
                         FOStoreServerConnection con)
Method Detail

handleRequest

RequestFinisher handleRequest()
                        throws java.io.IOException,
                               FOStoreDatabaseException
Description copied from class: RequestHandler
Subclasses implement this to take care of individiual requests.

Specified by:
handleRequest in class RequestHandler
Returns:
A RequestFinisher or null. If null, then no further work is required on behalf of this request. If a RequestFinisher is returned, then it is added to a list, and after all requests have been processed, the finishers in the list have their finish() method invoked on them. Finishers are invoked in the same order as the requests were.
Throws:
java.io.IOException
FOStoreDatabaseException

getOkToFinish

protected boolean getOkToFinish()
The RollbackHandler should override this and return false, so that finishers are not run when we are rolling back.


setOkToCommit

protected void setOkToCommit(boolean okToCommit)
The CommitHandler should override this and save the given value, then use it to determine whether or not to commit.


handleRequests

static void handleRequests(FOStoreServerConnection con)
Handles all requests that can be read at this time from the given connection. Reads the number of requests, then reads each one and, in turn, invokes the handleRequest operation on each.

The data it generates for the client is documented; see ReplyHandler.processReplies(java.io.DataInput, org.apache.jdo.impl.fostore.Message).

If after all requests are thusly handled, none have indicated that the second round of handling, called finishing, is not to be done, then performs this second round. The finishers that are invoked are precisely those which were returned from each request's handleRequest invocation, and the finishers have their finish() methods invoked in the same order in which the requests were originally invoked.

Finally, writes the number of replies (at the beginning of the reply data, in a spot that was set aside for this purpose), and sends replies back to the client.

This method is very paranoid about error checking, which clutters it up some, but is necessary to ensure that the server keeps running.