RE: [ebxmlms-general] Connectionpooling and transactions. was: Problems after lost connection to database

[Ronald v. K. <rtv...@xs...>]

Thanks, I'll have a look. Did you know btw that java.nio has file locking on filesystems which
support it. Could be a nice addition.

Ronald


Mattias J probeerde me het volgende duidelijk te maken:
> At 2005-07-06 09:43, you wrote:
>>Mathias.
>>
>>Good info. I'll have a look. This Jakarta Commons solution does not
>>come up in google if you use JTA in your search terms.
>>
>>Ok.. I had a quick look. Since it is not JTA/JCA compatible it seems
>>like a similar solution currently implemented in hermes. Then again,
>>it would not be wrong to drop these 'home made' extensions in favour
>>of existing ones right? (not that the home made solutions are bad,
>>not at all. My own cake is always better than the cake from the mall ;-)
>>
>>Is your solution a kind of java connector?
>
> Nope. I have very limited knowledge of JCA.
> It is a simple class wrapping java.io.File and implementing
> javax.transaction.xa.XAResource.
>
>>Can it be used as a drop-inn in any j2ee container?
>
> It assumes the transaction manager can be found in JNDI
> "java:comp/TransactionManager". But of course that can be made configurable.
>
>>If so, is it available to others ;-)
>
> It is both closed source and specific to our environment. We use it
> (mainly) when creating files. They are created as temporary files,
> and when the JTA transaction commits, the file is moved to the final
> destination and given the final name. If the transaction is rolled
> back, the file is deleted.
>
> Here is the outline of the implementation:
>
> In constructor of factory:
>        // Enlist as resource in transaction
>        TransactionManager tm = (TransactionManager)new
> InitialContext().lookup("java:comp/TransactionManager");
>        javax.transaction.Transaction tx = tm.getTransaction();
>        if(tx != null)
>          tx.enlistResource(this);
>
>    /** Manual delete */
>    public void delete()  { // NOTE! Assumes newly created files, does
> not work with existing files!
>      if(xid != null) { // If enlisted in transaction
>        // Delist from  transaction
>        TransactionManager tm = (TransactionManager)new
> InitialContext().lookup("java:comp/TransactionManager");
>        tm.getTransaction().delistResource(this, TMSUCCESS);
>      }
>      [[Perform delete]]
>    }
>
>    /**
>     * Close file and move to new directory. The method used by all
> other close methods internally.
>     * @param newPath
>     * @param newName
>     */
>    public final void rename(final String newName) {
>      if(xid == null) // If not part of a transaction
>        [[Perform rename]]
>      else
>        [[Remember name until commit]]
>    }
>
>    /////////////////////////////////////////////////////////////////////////////////////
>    // Methods to implement XAResource
>    /////////////////////////////////////////////////////////////////////////////////////
>
>    public int getTransactionTimeout() throws XAException {
>      return 0;
>    }
>
>    public boolean setTransactionTimeout(int i) throws XAException {
>      return false;
>    }
>
>    public boolean isSameRM(XAResource xaResource) throws XAException {
>      return xaResource == this; // If same file
>    }
>
>    public Xid[] recover(int flags) throws XAException {
>      return null;
>    }
>
>    /**
>     * Prepare for commit. After this we need to be sure the commit
> will be successful. For
>     * example we need to make sure there is enought disc space for the file.
>     */
>    public int prepare(Xid xid) throws XAException {
>      // We could do all the file flushing here
>      [[Assert file name is set]]
>      return XA_OK;
>    }
>
>    public void forget(Xid xid) throws XAException {
>      this.xid = null;
>    }
>
>    public void rollback(Xid xid) throws XAException {
>      this.xid = null;
>      [[Delete the file]]
>    }
>
>    public void end(Xid xid, int flags) throws XAException {
>    }
>
>    public void start(Xid xid, int flags) throws XAException {
>      this.xid = xid;
>    }
>
>    public void commit(Xid xid, boolean onePhase) throws XAException {
>      if([[File not yet manually deleted]]) { // Unless the file was
> deleted (and delisted)
>        [[Perform rename/move]]
>      }
>      this.xid = null;
>    }
>
>
>
> / Mattias Jiderhamn
>
>
>
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