Thanks Dasarath's reply.
--- Dasarath Weeratunge <[EMAIL PROTECTED]>写道:
> Quoting Jack Wang <[EMAIL PROTECTED]>:
>
> Let us assume a money transfer. You invoke the 2 services:
>
> Bank1.debit(acc1, dollars);
> Bank2.credit(acc2, dollars);
>
> Now Bank1 and Bank2 services could be running on hosts H1, H2 (H2 could be
> the
> same as H1) which we do not care.
>
> Say you have Kandula running on host H3 (could be the same as H1 or H2). Then
> you MUST set kandula.context to:
>
> http://H3:port/axis/services/
>
> and call your operations like this.
>
> wstm.begin("http://H3:port/axis/services/activationCoordinator";);
I try to follow it and here is my web application code in H3 running Kandula.
/* -- wstm begin in H3 ------- */
ActivationStub stub = new ActivationStub(new
EndpointReference("http://H3:port/axis/services/activationCoordinator";));
CoordinationContext ctx =
stub.createCoordinationContext(ATCoordinator.COORDINATION_TYPE_ID);
EndpointReference cps = ctx.register(ATCoordinator.PROTOCOL_ID_COMPLETION,
new
EndpointReference("http://H3:port/axis/services/completionInitiator";));
SetCoordCtxHandler.setCtx(ctx);
/* --------------------------- */
Question 1:
I wonder if I do not configure "UserTransaction" in H1 and H2's tomcats now
when I operate the
database in the web services of H1 and H2, which will be called by H3's
transaction. And Also
wonder if I do not configure "UserTransaction" in H3's tomcat , where there is
a local db
operation which will also be placed in the H3's same transaction.
In the normal application, I use UserTransaction configured in tomcat's
sever.xml to operate
database. The code is as follow:
/* -- normal db application ----------------- */
Context ctx = new InitialContext();
UserTransaction ut =
(UserTransaction)ctx.lookup("java:comp/env/UserTransaction");
DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/myDB");
java.sql.Connection conn = ds.getConnection();
ut.begin();
Statement stmt = conn.createStatement();
PreparedStatement pstmt = conn.prepareStatement("update ...");
...
pstmt.executeUpdate();
if (...) {
ut.commit();
} else {
ut.rollback();
}
/* ------------------------------------------ */
> Bank1.debit(acc1, dollars);
> Bank2.credit(acc2, dollars);
> wstm.commit();
>
> Note that the new o.a.k.coordinator.at.TMimpl expects to be called from
> within
> a ws container where kandula is deployed-- if you call it from a standalone
> your tx will work but the "commit" method will hang expecting a "Committed"
> message which cannot be received this way.
>
My application will be a ws container application, so not consider standalone
application.
>
> Say now, that YOU are providing Bank1 (or Bank2 or both)
>
> Now when you create a DataSource in JDBC it gives you an XAResource
> interface.
> You must register this XAResource interface with the local j2ee tx.
>
> e.g.
>
> Bank1.creditImpl(acc, dollars) {
>
> xaRes = createConnection("JDBC:connection string");
I try to follow it and here is my code in H1 or H2 to do the db transaction.
The database server
is mySQL 5.0 and I will use Connector/J 5.0 jdbc driver, so I can use
Distributed Transactions.
/* -----db transaction in H1 and H2 --------- */
MysqlXADataSource xaDs = new MysqlXADataSource();
XAConnection xaConn = xaDs.getXAConnection();
javax.transaction.xa.XAResource xaRes = xaConn.getXAResource();
/* ------------------------------------------ */
> Transaction tx = tm.getTransaction();
> tx.enlistResource(xaRes);
>
Question 2:
Class javax.transaction.TransactionManager is an interface used by application
container. I can
get a UserTransaction. Can I get a Transaction instance directly by
"Transaction tx =
javax.transaction.TransactionManager.getTransaction();" ? If not, how can I get
the local j2ee tx?
> // SQL statements
>
/* ----- SQL statements in H1 and H2 --------- */
Connection conn = xaConn.getConnection();
Xid xid = createXid();
xaRes.start(xid, XAResource.TMNOFLAGS);
conn.createStatement().executeUpdate("INSERT INTO testCoordination VALUES (1)");
xaRes.end(xid, XAResource.TMSUCCESS);
int ret = xaRes.prepare(xid);
if (ret == XAResource.XA_OK) {
xaRes.commit(xid, false);
} else{
xaRes.rollback(xid);
}
/* ------------------------------------------ */
Question 3:
If H3's transaction also contains a local database operation, I should let the
H3's local j2ee tx
enlist the xaRes in H3's bean, which will be called by a jsp's request. Is it
right?
> tx.delistResource(xaRes);
> }
>
> This usually happens transparently if your TM and DB are properly hooked up
> to
> your container-- say Tomcat. (However, I've not seen any docs on how to to do
> this with Geronimo but certainly it is possible.)
>
> Notice that there are 2 parallel sets of interfaces.
> o.a.k.coordinator.at.TransactionImpl,
> o.a.k.coordinator.at.TransactionManagerImpl
> and
> javax.transaction.Transaction, javax.transaction.TransactionManager.
>
> When you use j2ee (or JDBC) for distributed transactions using ws-at/kandula,
> your application will NOT directly get itself involved in ws-at protocol.
> instead it will as usual work with JTA. However, behind the scene, kandula
> will
> tie up your local JTA tx with the corresponding (global) ws-at tx so that
> your
> local tx becomes a branch of the global tx.
>
> --dasarath
Question 4:
The key problem is that I don't know how to get the local JTA(j2ee) tx, and how
kandula ties the
local tx with the corresponding (global) ws-at tx, please ask in which class
kandula ties them ?
Thanks again
Wang Jun
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