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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.datasource.xa;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Stack;
import java.util.Vector;
import javax.transaction.xa.XAException;
import javax.transaction.xa.XAResource;
import javax.transaction.xa.Xid;
import com.atomikos.datasource.RecoverableResource;
import com.atomikos.datasource.ResourceException;
import com.atomikos.datasource.ResourceTransaction;
import com.atomikos.datasource.TransactionalResource;
import com.atomikos.diagnostics.Console;
import com.atomikos.icatch.CompositeTransaction;
import com.atomikos.icatch.Participant;
import com.atomikos.icatch.RecoveryService;
import com.atomikos.icatch.SysException;
import com.atomikos.icatch.system.Configuration;
import com.atomikos.persistence.StateRecoveryManager;
/**
*
*
* An abstract XA implementation of a transactional resource.
*
* For a particular XA data source, it is necessary to implement the
* refreshXAConnection method, because in general there is no standard way of
* getting XAResource instances. Therefore, this class is agnostic about it.
*/
/*
* It is assumed that there is at most one instance per (root transaction,
* server) combination. Otherwise, siblings can not be mapped to the same
* ResourceTransaction! This instance is responsible for mapping siblings to
* ResourceTransaction instances.
*/
public abstract class XATransactionalResource implements TransactionalResource
{
protected XAResource xares_;
// the xa resource for which txs are created.
protected String servername_;
// needed for recovery: our xids' branchqualifiers start with this.
protected Hashtable recoveryMap_;
// contains all recovered Xid instances, for recovering Restxs.
protected Hashtable siblingmappers_;
// maps root
protected XidFactory xidFact_;
// factory for creating Xid objects: some databases
// required their own XID instance format.
private boolean closed_;
// true ASA close called.
private boolean weakCompare_;
// if true: do NOT delegate usesXAResource calls
// to the xaresource; needed for SONICMQ and other
// JMS that do not correctly implement isSameRM
private boolean compareAlwaysTrue_;
// if true, then isSameRM will ALWAYS return true
// this can be useful for cases where different
// JOINs don't have to work with lock sharing
// or for cases where XAResource classes
// are always non-compliant (like JBoss)
private String branchIdentifier_;
// the unique name that is used for all our XID branches
/**
* Construct a new instance with a default XidFactory.
*
* @param servername
* The servername, needed to identify the xid instances for the
* current configuration. Max BYTE length is 64!
*/
public XATransactionalResource ( String servername )
{
servername_ = servername;
siblingmappers_ = new Hashtable ();
// name should be less than 64 for xid compatibility
String maxLong = "" + Long.MAX_VALUE;
//branch id is server name + long value!
String testName = servername + maxLong;
if ( testName.getBytes ().length > 64 )
throw new RuntimeException (
"Max length of resource name exceeded: should be less than " + ( 64 - maxLong.getBytes().length ) );
xidFact_ = new DefaultXidFactory ();
closed_ = false;
weakCompare_ = false;
compareAlwaysTrue_ = false;
branchIdentifier_ = servername;
}
/**
* Construct a new instance with a custom XidFactory.
*
* @param servername
* The servername, needed to identify the xid instances for the
* current configuration. Max BYTE length is 64!
* @param factory
* The custom XidFactory.
*
*/
public XATransactionalResource ( String servername , XidFactory factory )
{
this ( servername );
xidFact_ = factory;
}
/**
* Utility method to establish and refresh the XAResource. An XAResource is
* actually a connection to a back-end resource, and this connection needs
* to stay open for the transactional resource instance. The resource uses
* the XAResource regularly, but sometimes the back-end server can close the
* connection after a time-out. At intialization time and also after such a
* time-out, this method is called to refresh the XAResource instance. This
* is typically done by (re-)establishing a connection to the server and
* keeping this connection open!.
*
* @return XAResource A XAResource instance that will be used to represent
* the server.
* @exception ResourceException
* On failure.
*/
protected abstract XAResource refreshXAConnection ()
throws ResourceException;
/**
* Get the xidFactory for this instance. Needed by XAResourceTransaction to
* create new XID.
*
* @return XidFactory The XidFactory for the resource.
*/
public XidFactory getXidFactory ()
{
return xidFact_;
}
protected void printMsg ( String msg , int level )
{
try {
Console console = Configuration.getConsole ();
if ( console != null ) {
console.println ( msg, level );
}
} catch ( Exception ignore ) {
}
}
void removeSiblingMap ( String root )
{
synchronized ( siblingmappers_ ) {
siblingmappers_.remove ( root );
}
}
SiblingMapper getSiblingMap ( String root )
{
synchronized ( siblingmappers_ ) {
if ( siblingmappers_.containsKey ( root ) )
return (SiblingMapper) siblingmappers_.get ( root );
else {
SiblingMapper map = new SiblingMapper ( this , root );
siblingmappers_.put ( root, map );
return map;
}
}
}
/**
* Check if the XAResource needs to be refreshed.
*
* @return boolean True if the XAResource needs refresh.
*/
protected boolean needsRefresh ()
{
boolean ret = true;
// check if connection has not timed out
try {
// we should be the same as ourselves!
// NOTE: xares_ is null if no connection could be gotten
// in that case we just return true
// otherwise, test the xaresource liveness
if ( xares_ != null ) {
xares_.isSameRM ( xares_ );
ret = false;
}
} catch ( XAException xa ) {
// timed out?
if ( Configuration.isDebugLoggingEnabled() ) Configuration.logDebug ( servername_
+ ": XAResource needs refresh?", xa );
}
return ret;
}
/**
* Set this instance to use the weak compare mode setting. This method
* should be called before recovery is done, so before
* initialization of the transaction service.
*
*
* this is no longer needed at all, and taken care of by the transaction
* service automatically.
*
* @return weakCompare True iff weak compare mode should be used. This mode
* is relevant for integration with certain vendors whose XAResource
* instances do not correctly implements isSameRM.
* @exception IllegalStateException
* If recovery was already done, meaning that the transaction
* service is already running.
*/
public void useWeakCompare ( boolean weakCompare )
{
weakCompare_ = weakCompare;
// FOLLOWING COMMENTED OUT TO ALLOW JMX ONLINE CONFIG
// if ( recoveryMap_ != null )
// throw new IllegalStateException (
// "useWeakCompare should not be called after recovery was done" );
// weakCompare_ = weakCompare;
}
/**
* Test if this instance uses weak compare mode.
*
*
* @return boolean True iff weak compare mode is in use. This mode is
* relevant for integration with certain vendors whose XAResource
* instances do not correctly implement isSameRM.
*/
public boolean usesWeakCompare ()
{
return weakCompare_;
}
/**
*
* Specify whether to entirely shortcut the isSameRM method of the
* XAResource implementations, and always return true for usesXAResource.
* The consequence is that branches are always different (even in the same
* tx) and that the resource names will not entirely match in the logfiles.
* Besides that, no serious problems should happen.
*
* @param val
*/
public void setAcceptAllXAResources ( boolean val )
{
compareAlwaysTrue_ = val;
}
/**
*
* @return boolean True if usesXAResource is always true.
*/
public boolean acceptsAllXAResources ()
{
return compareAlwaysTrue_;
}
/**
* Test if the XAResource is used by this instance.
*
* @param xares
* The XAResource to test.
* @return boolean True iff this instance uses the same back-end resource,
* in as far as this can be determined by this instance.
*/
public boolean usesXAResource ( XAResource xares )
{
// entirely shortcut normal behaviour if desired
if ( acceptsAllXAResources () )
return true;
XAResource xaresource = getXAResource ();
if ( xaresource == null )
return false;
// if no connection could be gotten
boolean ret = false;
if ( !xares.getClass ().getName ().equals (
xaresource.getClass ().getName () ) ) {
// if the implementation classes are different,
// the resources are not the same
// this check is needed to cope with
// vendor-specific errors in XAResource.isSameRM()
ret = false;
} else {
// in this case, the implementation class names are the same
// so delegate to xares instances
try {
if ( xares.isSameRM ( xaresource ) ) {
ret = true;
} else if ( usesWeakCompare () ) {
// In weak compare mode, it does not matter if the resource
// says it is different. The fact that the implementation is
// the
// same is enough. Needed for SONICMQ and others.
ret = true;
} else {
Configuration
.logDebug ( "XAResources claim to be different: "
+ xares + " and " + xaresource );
}
} catch ( XAException xe ) {
Stack errors = new Stack ();
errors.push ( xe );
throw new SysException ( "Error in XAResource comparison: "
+ xe.getMessage (), errors );
}
}
return ret;
}
/**
* Get the XAResource instance that this instance is using.
*
* @return XAResource The XAResource instance.
*/
public synchronized XAResource getXAResource ()
{
// null on first invocation
if ( needsRefresh () ) {
Configuration
.logDebug ( servername_ + ": refreshing XAResource..." );
xares_ = refreshXAConnection ();
Configuration.logInfo ( servername_ + ": refreshed XAResource" );
}
// first, check if connection has not timed out
// try {
// //we should be the same as ourselves!
// //NOTE: xares_ is null if no connection could be gotten
// //in that case we just return null
// //otherwise, test the xaresource liveness
// if ( xares_ != null ) xares_.isSameRM ( xares_ );
// }
// catch ( XAException xa ) {
// //timed out?
// xares_ = refreshXAConnection();
// }
return xares_;
}
/**
* @see TransactionalResource
*/
public ResourceTransaction getResourceTransaction ( CompositeTransaction ct )
throws ResourceException, IllegalStateException
{
if ( closed_ )
throw new IllegalStateException (
"XATransactionResource already closed" );
// because instances are created on a per-root basis, here we can assume
// that the last used ResourceTransaction was for a sibling!
if ( ct == null )
return null; // happens in create method of beans
// String root = ct.getCompositeCoordinator().getRootTid();
// CHANGED FOR 3.0: Take TOPMOST root ID, since local subtxs have
// different root ID
Stack lineage = ct.getLineage ();
String root = null;
if ( lineage == null || lineage.isEmpty () )
root = ct.getTid ();
else {
Stack tmp = (Stack) lineage.clone ();
while ( !tmp.isEmpty () ) {
CompositeTransaction next = (CompositeTransaction) tmp.pop ();
if ( next.isRoot () )
root = next.getTid ();
}
}
return (getSiblingMap ( root )).map ( ct );
}
private StateRecoveryManager getRecoveryManager () throws ResourceException
{
if ( closed_ )
throw new IllegalStateException (
"XATransactionResource already closed" );
// for XA resources, there is no compensation and hence
// no internal recovery manager.
return null;
}
/**
* @see TransactionalResource
*/
public String getName ()
{
return servername_;
}
/**
* The default close operation. Subclasses may need to override this method
* in order to process XA-specific close procedures such as closing
* connections.
*
*/
public void close () throws ResourceException
{
closed_ = true;
}
/**
* Test if the resource is closed.
*
* @return boolean True if closed.
* @throws ResourceException
*/
public boolean isClosed () throws ResourceException
{
return closed_;
}
/**
* @see RecoverableResource
*/
public boolean isSameRM ( RecoverableResource res )
throws ResourceException
{
if ( res == null || !(res instanceof XATransactionalResource) )
return false;
XATransactionalResource xatxres = (XATransactionalResource) res;
if ( xatxres.servername_ == null || servername_ == null )
return false;
return xatxres.servername_.equals ( servername_ );
}
/**
* @see RecoverableResource
*/
public void setRecoveryService ( RecoveryService recoveryService )
throws ResourceException
{
// null during testing
if ( recoveryService != null ) {
if ( Configuration.isDebugLoggingEnabled() ) Configuration.logDebug ( "Installing recovery service on resource "
+ getName () );
branchIdentifier_ = recoveryService.getName ();
recoveryService.recover ();
}
// DON'T call endRecovery here, since the TM
// will do this (otherwise, only this resource
// will know).
}
/**
* @see TransactionalResource
*/
public synchronized boolean recover ( Participant participant )
throws ResourceException
{
boolean recovered = true;
if ( closed_ )
throw new IllegalStateException (
"XATransactionResource already closed" );
if ( !(participant instanceof XAResourceTransaction) )
throw new ResourceException ( "Wrong argument class: "
+ participant.getClass ().getName () );
XAResource xaresource = getXAResource ();
// if no connection then we can't recover the participant
if ( xaresource == null ) {
Configuration.logWarning ( "XATransactionalResource " + getName() +
": XAResource is NULL!" );
return false;
}
XAResourceTransaction xarestx = (XAResourceTransaction) participant;
if ( recoveryMap_ == null )
recover ();
if ( !recoveryMap_.containsKey ( xarestx.getXid() ) ) {
//TAKE CARE: if multiple resources 'recover' the same Xid from the same backend
//then this will be a problem here: endRecovery will rollback a transaction
//as per presumed abort!
recovered = false;
}
//also set xaresource if resource name is the same:
//this happens if VM exits between XA commit and log flush
//-> should lead to NOTA in commit
//see case 21552
if ( recovered || getName().equals ( xarestx.getResourceName() ) )
xarestx.setRecoveredXAResource ( getXAResource () );
recoveryMap_.remove ( xarestx.getXid() );
return recovered;
}
/**
* Recover the contained XAResource, and retrieve the xid instances that
* start with our server's name.
*
* @exception ResourceException
* If a failure occurs.
*/
protected void recover () throws ResourceException
{
recoveryMap_ = new Hashtable ();
Xid[] recoveredlist = null;
int flags = XAResource.TMSTARTRSCAN;
boolean done = false;
Stack errors = new Stack ();
Vector recoveredXids = new Vector ();
// this vector contains ALL recovered Xids so far,
// to check if a scan returns duplicate results
// this is needed for oracle8.1.7
// if ( branchIdentifier_ == null ) throw new ResourceException (
// "Recovery service not set for resource " + getName() );
printMsg ( "recovery initiated for resource " + getName ()
+ " with branchIdentifier " + branchIdentifier_, Console.DEBUG );
do {
try {
recoveredlist = getXAResource ().recover ( flags );
} catch ( NullPointerException ora ) {
//Typical for Oracle without XA setup
if ( getXAResource ().getClass ().getName ().toLowerCase ().indexOf ( "oracle" ) >= 0 ) {
printMsg ( "ORACLE NOT CONFIGURED FOR XA? PLEASE CONTACT YOUR DBA TO FIX THIS..." , Console.WARN );
}
throw ora;
} catch ( XAException xaerr ) {
Configuration.logWarning ( "Error in recovery", xaerr );
errors.push ( xaerr );
throw new ResourceException ( "Error in recovery", errors );
}
flags = XAResource.TMNOFLAGS;
done = (recoveredlist == null || recoveredlist.length == 0);
if ( !done ) {
// TEMPTATIVELY SET done TO TRUE
// TO TOLERATE ORACLE 8.1.7 INFINITE
// LOOP (ALWAYS RETURNS SAME RECOVER
// SET). IF A NEW SET OF XIDS IS RETURNED
// THEN done WILL BE RESET TO FALSE
done = true;
for ( int i = 0; i < recoveredlist.length; i++ ) {
Xid xid = new XID ( recoveredlist[i] );
// our own XID implements equals and hashCode properly
if ( !recoveredXids.contains ( xid ) ) {
// a new xid is returned -> we can not be in a
// recovery loop -> go on
printMsg ( "Resource " + servername_
+ " inspecting XID: " + xid, Console.INFO );
recoveredXids.addElement ( xid );
done = false;
// only really 'recover' this xid if it is from
// this server
String branch = new String ( recoveredlist[i]
.getBranchQualifier () );
if ( branch.startsWith ( branchIdentifier_ ) ) {
recoveryMap_.put ( xid, new Object () );
printMsg ( "Resource " + servername_
+ " recovering XID: " + xid, Console.INFO );
} else {
printMsg ( "Resource " + servername_ + ": XID "
+ xid + " with branch " + branch
+ " is not under my responsibility",
Console.INFO );
}
}
}
}
} while ( !done );
// allow early GC of recovered Xid list
recoveredXids = null;
}
/**
* @see TransactionalResource.
*/
public void endRecovery () throws ResourceException
{
if ( closed_ )
throw new IllegalStateException (
"XATransactionResource already closed" );
XAResource xaresource = getXAResource ();
// if xaresource is null then we can't do rollback
// this is acceptable, since the only xids that
// will be aborted are those who are ONLY indoubt
// in the database, not in the TM. The DB
// administrator can rollback those manually without
// anything else
if ( xaresource == null )
return;
// recovery map is null if no logged coordinators existed
// in that case, make sure that possible indoubts (of
// VOTING ergo non-recoverable coordinators)
// are recovered now. Otherwise, they will not be rolled back.
if ( recoveryMap_ == null )
recover ();
Enumeration toAbortList = recoveryMap_.keys ();
while ( toAbortList.hasMoreElements () ) {
XID xid = (XID) toAbortList.nextElement ();
try {
xaresource.rollback ( xid );
// getXAResource().rollback ( xid );
printMsg ( "XAResource.rollback ( " + xid + " ) called "
+ "on resource " + servername_, Console.INFO );
} catch ( XAException xaerr ) {
// here, an indoubt tx might remain in resource; we do nothing
// to prevent this and leave it to admin tools
}
}
// ADDED: to enable repeated recovery calls
recoveryMap_ = null;
printMsg ( "endRecovery() done for resource " + getName (),
Console.DEBUG );
}
/**
* Set the XID factory, needed for online management tools.
*
* @param factory
*/
public void setXidFactory ( XidFactory factory )
{
xidFact_ = factory;
}
/**
* Create an XID for the given tx.
*
* @param tid
* The tx id.
* @return Xid A globally unique Xid that can be recovered by any resource
* that connects to the same EIS.
*/
protected Xid createXid ( String tid )
{
return getXidFactory ().createXid ( tid, branchIdentifier_ );
}
}
