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/**
 * Copyright (C) 2000-2010 Atomikos 
 *
 * This code ("Atomikos TransactionsEssentials"), by itself,
 * is being distributed under the
 * Apache License, Version 2.0 ("License"), a copy of which may be found at
 * http://www.atomikos.com/licenses/apache-license-2.0.txt .
 * You may not use this file except in compliance with the License.
 *
 * While the License grants certain patent license rights,
 * those patent license rights only extend to the use of
 * Atomikos TransactionsEssentials by itself.
 *
 * This code (Atomikos TransactionsEssentials) contains certain interfaces
 * in package (namespace) com.atomikos.icatch
 * (including com.atomikos.icatch.Participant) which, if implemented, may
 * infringe one or more patents held by Atomikos.
 * It should be appreciated that you may NOT implement such interfaces;
 * licensing to implement these interfaces must be obtained separately from Atomikos.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 */

package com.atomikos.icatch.jta;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.rmi.RemoteException;
import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.naming.RefAddr;
import javax.naming.Reference;
import javax.naming.Referenceable;
import javax.naming.StringRefAddr;
import javax.rmi.PortableRemoteObject;
import javax.transaction.NotSupportedException;
import javax.transaction.Status;
import javax.transaction.SystemException;
import javax.transaction.Transaction;
import javax.transaction.TransactionManager;
import javax.transaction.UserTransaction;

import com.atomikos.icatch.system.Configuration;

/**
 * 
 * 
 * An implementation of a (remote) client's user transaction. When
 * client-demarcated transactions are enabled, this is the kind of
 * UserTransaction you get by calling getUserTransaction() on the
 * UserTransactionService. Client applications can use the result to control
 * transaction demarcation, and even pass their instance to other VMs so that
 * those can share the same transaction context. The server-side applications
 * can use the toString() method to obtain the transaction identifier of the
 * transaction represented by an instance. This way, an incoming call from a
 * client that demarcates its own transactions only has to ship the
 * UserTransaction to the server (or to other clients) to identify what
 * transaction it is in. 
* * NOTE: remote clients that use instances of this class can do transaction * demarcation, but they can not do nested transactions!
* * NOTE: instances that are meant to be bound in JNDI should be bound without * any transaction context (i.e., without calling begin() first). */ public final class RemoteClientUserTransaction implements UserTransaction, Externalizable, Referenceable { static final int DEFAULT_TIMEOUT = 30; private transient UserTransactionServer txmgrServer_; // not null if used outside server VM private transient TransactionManager txmgr_; // not null if used in server VM private transient Hashtable threadToTidMap_; private int timeout_; private String name_; // the RMI name to lookup the remote server. private String initialContextFactory_; private String providerUrl_; private boolean imported_; // if true: no commit/rollback allowed // this is the case for instances that are // passed on between remote clients // Only the client that begins the tx // may commit/abort it. /** * No-argument constructor, as required by Externalizable interface. */ public RemoteClientUserTransaction () { threadToTidMap_ = new Hashtable (); timeout_ = DEFAULT_TIMEOUT; imported_ = false; } /** * Preferred constructor. * * @param name * The unique name of the UserTransactionServer. * @param initialContextFactory * The initial context factory of the server JNDI * context. * @param providerUrl * The provider URL of the server JNDI context. */ public RemoteClientUserTransaction ( String name , String initialContextFactory , String providerUrl ) { initialContextFactory_ = initialContextFactory; providerUrl_ = providerUrl; name_ = name; threadToTidMap_ = new Hashtable (); timeout_ = DEFAULT_TIMEOUT; imported_ = false; } // /** // *For use by JNDI factory // */ // // RemoteClientUserTransaction ( String url ) // { // this(); // name_ = url; // } private String getNotFoundMessage () { String errorMsg = "Name not found: " + name_ + "\n" + "Please check that: \n" + " -server property com.atomikos.icatch.client_demarcation is set to true \n" + " -server property com.atomikos.icatch.rmi_export_class is correct \n" + " -server property java.naming.factory.initial is " + initialContextFactory_ + "\n" + " -server property java.naming.provider.url is " + providerUrl_ + "\n" + " -the naming service is running on port " + providerUrl_ + "\n" + " -the transaction server is running"; return errorMsg; } /** * Referenceable mechanism requires later setup of txmgr_, otherwise binding * into JNDI already requires that TM is running. * * @return boolean True if running in server VM, false if remote. */ private boolean checkSetup () { // first try to get intra-VM txmgr txmgr_ = TransactionManagerImp.getTransactionManager (); // if no intra-VM tm: use remote tm if ( txmgr_ == null ) { try { Hashtable env = new Hashtable (); env.put ( Context.INITIAL_CONTEXT_FACTORY, initialContextFactory_ ); env.put ( Context.PROVIDER_URL, providerUrl_ ); Context ctx = new InitialContext ( env ); txmgrServer_ = (UserTransactionServer) PortableRemoteObject .narrow ( ctx.lookup ( name_ ), UserTransactionServer.class ); } catch ( Exception e ) { e.printStackTrace (); throw new RuntimeException ( getNotFoundMessage () ); } if ( txmgrServer_ == null ) throw new RuntimeException ( getNotFoundMessage () ); } return txmgr_ != null; } private synchronized void setThreadMapping ( String tid ) { Thread thread = Thread.currentThread (); threadToTidMap_.put ( thread, tid ); } private synchronized String removeThreadMapping () { Thread thread = Thread.currentThread (); return (String) threadToTidMap_.remove ( thread ); } private synchronized String getThreadMapping () { Thread thread = Thread.currentThread (); return (String) threadToTidMap_.get ( thread ); } /** * @see javax.transaction.UserTransaction */ public void begin () throws NotSupportedException, SystemException { boolean local = checkSetup (); if ( local ) txmgr_.begin (); else { String tid = getThreadMapping (); if ( tid != null ) { // error: no nested txs supported throw new NotSupportedException ( "Nested transaction not allowed here" ); } try { tid = txmgrServer_.begin ( timeout_ ); } catch ( RemoteException re ) { throw new SystemException ( re.getMessage () ); } setThreadMapping ( tid ); } } /** * @see javax.transaction.UserTransaction */ public void commit () throws javax.transaction.RollbackException, javax.transaction.HeuristicMixedException, javax.transaction.HeuristicRollbackException, javax.transaction.SystemException, java.lang.IllegalStateException, java.lang.SecurityException { boolean local = checkSetup (); if ( local ) txmgr_.commit (); else { if ( imported_ ) throw new SecurityException ( "Commit not allowed: not creator" ); String tid = removeThreadMapping (); if ( tid == null ) throw new IllegalStateException ( "No transaction for thread" ); try { txmgrServer_.commit ( tid ); } catch ( RemoteException re ) { throw new SystemException ( re.getMessage () ); } } } /** * @see javax.transaction.UserTransaction */ public void rollback () throws IllegalStateException, SystemException, SecurityException { boolean local = checkSetup (); if ( local ) txmgr_.rollback (); else { if ( imported_ ) throw new SecurityException ( "Rollback not allowed: not creator" ); String tid = removeThreadMapping (); if ( tid == null ) throw new IllegalStateException ( "No transaction for thread" ); try { txmgrServer_.rollback ( tid ); } catch ( RemoteException re ) { throw new SystemException ( re.getMessage () ); } } } /** * @see javax.transaction.UserTransaction */ public void setRollbackOnly () throws IllegalStateException, SystemException { boolean local = checkSetup (); if ( local ) txmgr_.setRollbackOnly (); else { String tid = getThreadMapping (); if ( tid == null ) throw new IllegalStateException ( "No transaction for thread" ); try { txmgrServer_.setRollbackOnly ( tid ); } catch ( RemoteException re ) { throw new SystemException ( re.getMessage () ); } } } /** * @see javax.transaction.UserTransaction */ public int getStatus () throws SystemException { int ret = Status.STATUS_NO_TRANSACTION; boolean local = checkSetup (); if ( local ) ret = txmgr_.getStatus (); else { String tid = getThreadMapping (); if ( tid != null ) { try { ret = txmgrServer_.getStatus ( tid ); } catch ( RemoteException re ) { throw new SystemException ( re.getMessage () ); } } } return ret; } /** * @see javax.transaction.UserTransaction */ public void setTransactionTimeout ( int seconds ) throws SystemException { timeout_ = seconds; } /** * Overrides the default behaviour, to allow retrieving the corresponding * transaction at the server side. * * @return String The transaction ID (tid) of the transaction for which the * thread is executing. Null if no transaction. */ public String toString () { String ret = null; boolean local = checkSetup (); if ( local ) { Transaction tx = null; try { tx = txmgr_.getTransaction (); } catch ( SystemException e ) { String msg = "Error getting transaction"; Configuration.logWarning ( msg, e ); } if ( tx != null ) ret = tx.toString (); } // happens if not local, OR: // if local, but no tx found for thread // this occurs for an imported instance // from a remote client!!! if ( ret == null ) ret = getThreadMapping (); return ret; } // // // IMPLEMENTATION OF REFERENCEABLE // // /** * @see Referenceable */ public Reference getReference () throws NamingException { RefAddr nameRef = new StringRefAddr ( "ServerName", name_ ); RefAddr urlRef = new StringRefAddr ( "ProviderUrl", providerUrl_ ); RefAddr factRef = new StringRefAddr ( "ContextFactory", initialContextFactory_ ); RefAddr timeoutRef = new StringRefAddr ( "Timeout", new Integer ( timeout_ ).toString () ); Reference ref = new Reference ( getClass ().getName (), new StringRefAddr ( "name", "RemoteClientUserTransaction" ), RemoteClientUserTransactionFactory.class.getName (), null ); ref.add ( nameRef ); ref.add ( urlRef ); ref.add ( factRef ); ref.add ( timeoutRef ); return ref; } // // // IMPLEMENTATION OF EXTERNALIZABLE // // /** * @see Externalizable */ public void writeExternal ( ObjectOutput out ) throws IOException { // Implement two-fold behaviour: // if thread not currently associated with a tx // then write null; // else write the current TID in order // to ship context among remote clients. String tid = getThreadMapping (); out.writeObject ( tid ); out.writeObject ( name_ ); out.writeObject ( initialContextFactory_ ); out.writeObject ( providerUrl_ ); out.writeInt ( timeout_ ); } /** * @see Externalizable */ public void readExternal ( ObjectInput in ) throws IOException, ClassNotFoundException { // Try if a tid is there; // if yes then this means that the streaming out // was done for a transaction context; // hence restore that context String tid = (String) in.readObject (); if ( tid != null ) { setThreadMapping ( tid ); imported_ = true; // this will mark the instance to not // allow commit/rollback } name_ = (String) in.readObject (); initialContextFactory_ = (String) in.readObject (); providerUrl_ = (String) in.readObject (); timeout_ = in.readInt (); } }




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