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package javax.transaction.xa;

/** <p>The XAResource interface is a Java mapping of the industry standard

  * XA interface based on the X/Open CAE Specification (Distributed

  * Transaction Processing: The XA Specification).

  *

  * <p>The XA interface defines the contract between a Resource Manager

  * and a Transaction Manager in a distributed transaction processing

  * (DTP) environment. A JDBC driver or a JMS provider implements

  * this interface to support the association between a global transaction

  * and a database or message service connection.

  *

  * <p>The XAResource interface can be supported by any transactional

  * resource that is intended to be used by application programs in an

  * environment where transactions are controlled by an external

  * transaction manager. An example of such a resource is a database

  * management system. An application may access data through multiple

  * database connections. Each database connection is enlisted with

  * the transaction manager as a transactional resource. The transaction

  * manager obtains an XAResource for each connection participating

  * in a global transaction. The transaction manager uses the

  * <code>start</code> method

  * to associate the global transaction with the resource, and it uses the

  * <code>end</code> method to disassociate the transaction from

  * the resource. The resource

  * manager is responsible for associating the global transaction to all

  * work performed on its data between the start and end method invocations.

  *

  * <p>At transaction commit time, the resource managers are informed by

  * the transaction manager to prepare, commit, or rollback a transaction

  * according to the two-phase commit protocol.</p>

  *

  */

public interface XAResource

{

    /** Commits the global transaction specified by xid.

      *

      * @param xid A global transaction identifier

      *

      * @param onePhase If true, the resource manager should use a one-phase

      * commit protocol to commit the work done on behalf of xid.

      *

      * @exception XAException An error has occurred. Possible XAExceptions

      * are XA_HEURHAZ, XA_HEURCOM, XA_HEURRB, XA_HEURMIX, XAER_RMERR,

      * XAER_RMFAIL, XAER_NOTA, XAER_INVAL, or XAER_PROTO.

      *

      * <P>If the resource manager did not commit the transaction and the

      *  paramether onePhase is set to true, the resource manager may throw

      *  one of the XA_RB* exceptions. Upon return, the resource manager has

      *  rolled back the branch's work and has released all held resources.

      */

    void commit(Xid xid, boolean onePhase) throws XAException;

    /** Ends the work performed on behalf of a transaction branch.

      * The resource manager disassociates the XA resource from the

      * transaction branch specified and lets the transaction

      * complete.

      *

      * <p>If TMSUSPEND is specified in the flags, the transaction branch

      * is temporarily suspended in an incomplete state. The transaction

      * context is in a suspended state and must be resumed via the

      * <code>start</code> method with TMRESUME specified.</p>

      *

      * <p>If TMFAIL is specified, the portion of work has failed.

      * The resource manager may mark the transaction as rollback-only</p>

      *

      * <p>If TMSUCCESS is specified, the portion of work has completed

      * successfully.</p>

      *

      * @param xid A global transaction identifier that is the same as

      * the identifier used previously in the <code>start</code> method.

      *

      * @param flags One of TMSUCCESS, TMFAIL, or TMSUSPEND.

      *

      * @exception XAException An error has occurred. Possible XAException

      * values are XAER_RMERR, XAER_RMFAILED, XAER_NOTA, XAER_INVAL,

      * XAER_PROTO, or XA_RB*.

      */

    void end(Xid xid, int flags) throws XAException;

    /** Tells the resource manager to forget about a heuristically

      * completed transaction branch.

      *

      * @param xid A global transaction identifier.

      *

      * @exception XAException An error has occurred. Possible exception

      * values are XAER_RMERR, XAER_RMFAIL, XAER_NOTA, XAER_INVAL, or

      * XAER_PROTO.

      */

    void forget(Xid xid) throws XAException;

    /** Obtains the current transaction timeout value set for this

      * XAResource instance. If <CODE>XAResource.setTransactionTimeout</CODE>

      * was not used prior to invoking this method, the return value

      * is the default timeout set for the resource manager; otherwise,

      * the value used in the previous <CODE>setTransactionTimeout</CODE>

      * call is returned.

      *

      * @return the transaction timeout value in seconds.

      *

      * @exception XAException An error has occurred. Possible exception

      * values are XAER_RMERR and XAER_RMFAIL.

      */

    int getTransactionTimeout() throws XAException;

    /** This method is called to determine if the resource manager

      * instance represented by the target object is the same as the

      * resouce manager instance represented by the parameter <i>xares</i>.

      *

      * @param xares An XAResource object whose resource manager instance

      *      is to be compared with the resource manager instance of the

      *      target object.

      *

      * @return <i>true</i> if it's the same RM instance; otherwise

      *       <i>false</i>.

      *

      * @exception XAException An error has occurred. Possible exception

      * values are XAER_RMERR and XAER_RMFAIL.

      *

      */

    boolean isSameRM(XAResource xares) throws XAException;

    /** Ask the resource manager to prepare for a transaction commit

      * of the transaction specified in xid.

      *

      * @param xid A global transaction identifier.

      *

      * @exception XAException An error has occurred. Possible exception

      * values are: XA_RB*, XAER_RMERR, XAER_RMFAIL, XAER_NOTA, XAER_INVAL,

      * or XAER_PROTO.

      *

      * @return A value indicating the resource manager's vote on the

      * outcome of the transaction. The possible values are: XA_RDONLY

      * or XA_OK. If the resource manager wants to roll back the

      * transaction, it should do so by raising an appropriate XAException

      * in the prepare method.

      */

    int prepare(Xid xid) throws XAException;

    /** Obtains a list of prepared transaction branches from a resource

      * manager. The transaction manager calls this method during recovery

      * to obtain the list of transaction branches that are currently in

      * prepared or heuristically completed states.

      *

      * @param flag One of TMSTARTRSCAN, TMENDRSCAN, TMNOFLAGS. TMNOFLAGS

      * must be used when no other flags are set in the parameter.

      *

      * @exception XAException An error has occurred. Possible values are

      * XAER_RMERR, XAER_RMFAIL, XAER_INVAL, and XAER_PROTO.

      *

      * @return The resource manager returns zero or more XIDs of the

      * transaction branches that are currently in a prepared or

      * heuristically completed state. If an error occurs during the

      * operation, the resource manager should throw the appropriate

      * XAException.

      *

      */

    Xid[] recover(int flag) throws XAException;

    /** Informs the resource manager to roll back work done on behalf

      * of a transaction branch.

      *

      * @param xid A global transaction identifier.

      *

      * @exception XAException An error has occurred.

      */

    void rollback(Xid xid) throws XAException;

    /** <P>Sets the current transaction timeout value for this <CODE>XAResource</CODE>

      * instance. Once set, this timeout value is effective until

      * <code>setTransactionTimeout</code> is invoked again with a different

      * value. To reset the timeout value to the default value used by the resource

      * manager, set the value to zero.

      *

      * If the timeout operation is performed successfully, the method returns

      * <i>true</i>; otherwise <i>false</i>. If a resource manager does not

      * support explicitly setting the transaction timeout value, this method

      * returns <i>false</i>.

      *

      * @param seconds The transaction timeout value in seconds.

      *

      * @return <i>true</i> if the transaction timeout value is set successfully;

      *       otherwise <i>false</i>.

      *

      * @exception XAException An error has occurred. Possible exception values

      * are XAER_RMERR, XAER_RMFAIL, or XAER_INVAL.

      */

    boolean setTransactionTimeout(int seconds) throws XAException;

    /** Starts work on behalf of a transaction branch specified in

      * <code>xid</code>.

      *

      * If TMJOIN is specified, the start applies to joining a transaction

      * previously seen by the resource manager. If TMRESUME is specified,

      * the start applies to resuming a suspended transaction specified in the

      * parameter <code>xid</code>.

      *

      * If neither TMJOIN nor TMRESUME is specified and the transaction

      * specified by <code>xid</code> has previously been seen by the resource

      * manager, the resource manager throws the XAException exception with

      * XAER_DUPID error code.

      *

      * @param xid A global transaction identifier to be associated

      * with the resource.

      *

      * @param flags One of TMNOFLAGS, TMJOIN, or TMRESUME.

      *

      * @exception XAException An error has occurred. Possible exceptions

      * are XA_RB*, XAER_RMERR, XAER_RMFAIL, XAER_DUPID, XAER_OUTSIDE,

      * XAER_NOTA, XAER_INVAL, or XAER_PROTO.

      *

      */

    void start(Xid xid, int flags) throws XAException;

    /**

      * Ends a recovery scan.

      */

    public final static int TMENDRSCAN =   0x00800000;

    /**

      * Disassociates the caller and marks the transaction branch

      * rollback-only.

      */

    public final static int TMFAIL =       0x20000000;

    /**

      * Caller is joining existing transaction branch.

      */

    public final static int TMJOIN =       0x00200000;

    /**

      * Use TMNOFLAGS to indicate no flags value is selected.

      */

    public final static int TMNOFLAGS =     0x00000000;

    /**

      * Caller is using one-phase optimization.

      */

    public final static int TMONEPHASE =   0x40000000;

    /**

      * Caller is resuming association with a suspended

      * transaction branch.

      */

    public final static int TMRESUME =     0x08000000;

    /**

      * Starts a recovery scan.

      */

    public final static int TMSTARTRSCAN = 0x01000000;

    /**

      * Disassociates caller from a transaction branch.

      */

    public final static int TMSUCCESS =    0x04000000;

    /**

      * Caller is suspending (not ending) its association with

      * a transaction branch.

      */

    public final static int TMSUSPEND =    0x02000000;

    /**

     * The transaction branch has been read-only and has been committed.

     */

    public final static int XA_RDONLY = 0x00000003;

    /**

     * The transaction work has been prepared normally.

     */

    public final static int XA_OK = 0;

}