/*
* Copyright (C) 2006-2013 Bitronix Software (http://www.bitronix.be)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package bitronix.tm.internal;
import bitronix.tm.BitronixXid;
import bitronix.tm.TransactionManagerServices;
import bitronix.tm.resource.common.XAResourceHolder;
import bitronix.tm.utils.Scheduler;
import bitronix.tm.utils.Uid;
import bitronix.tm.utils.UidGenerator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.transaction.xa.XAException;
import javax.transaction.xa.XAResource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;
/**
* Every {@link bitronix.tm.BitronixTransaction} contains an instance of this class that is used to register
* and keep track of resources enlisted in a transaction.
*
* @author Ludovic Orban
*/
public class XAResourceManager {
private final static Logger log = LoggerFactory.getLogger(XAResourceManager.class);
private final Uid gtrid;
private final Scheduler<XAResourceHolderState> resources = new Scheduler<XAResourceHolderState>();
/**
* Create a resource manager for the specified GTRID.
* @param gtrid the transaction's GTRID this XAResourceManager will be assigned to.
*/
public XAResourceManager(Uid gtrid) {
this.gtrid = gtrid;
}
/**
* Enlist the specified {@link XAResourceHolderState}. A XID is generated and the resource is started with
* XAResource.TMNOFLAGS or XAResource.TMJOIN if it could be joined with another previously enlisted one.
* <br/>
* There are 3 different cases that can happen when a {@link XAResourceHolderState} is enlisted:
* <ul>
* <li>already enlisted and not ended: do nothing</li>
* <li>already enlisted and ended: try to join. if you can join, keep a reference on the passed-in
* {@link XAResourceHolderState} and drop the previous one. if you cannot join, it's the same as case 3</li>
* <li>not enlisted: create a new branch and keep a reference on the passed-in {@link XAResourceHolderState}</li>
* </ul>
*
* @param xaResourceHolderState the {@link XAResourceHolderState} to be enlisted.
* @throws XAException if a resource error occured.
* @throws BitronixSystemException if an internal error occured.
*/
public void enlist(XAResourceHolderState xaResourceHolderState) throws XAException, BitronixSystemException {
XAResourceHolderState alreadyEnlistedHolder = findXAResourceHolderState(xaResourceHolderState.getXAResource());
if (alreadyEnlistedHolder != null && !alreadyEnlistedHolder.isEnded()) {
xaResourceHolderState.setXid(alreadyEnlistedHolder.getXid());
log.warn("ignoring enlistment of already enlisted but not ended resource " + xaResourceHolderState);
return;
}
XAResourceHolderState toBeJoinedHolderState = null;
if (alreadyEnlistedHolder != null) {
if (log.isDebugEnabled()) { log.debug("resource already enlisted but has been ended eligible for join: " + alreadyEnlistedHolder); }
toBeJoinedHolderState = getManagedResourceWithSameRM(xaResourceHolderState);
}
BitronixXid xid;
int flag;
if (toBeJoinedHolderState != null) {
if (log.isDebugEnabled()) { log.debug("joining " + xaResourceHolderState + " with " + toBeJoinedHolderState); }
xid = toBeJoinedHolderState.getXid();
flag = XAResource.TMJOIN;
}
else {
xid = UidGenerator.generateXid(gtrid);
if (log.isDebugEnabled()) { log.debug("creating new branch with " + xid); }
flag = XAResource.TMNOFLAGS;
}
// check for enlistment of a 2nd LRC resource, forbid this if the 2nd resource cannot be joined with the 1st one
// unless this is explicitly allowed in the config
if (flag != XAResource.TMJOIN && xaResourceHolderState.getTwoPcOrderingPosition() == Scheduler.ALWAYS_LAST_POSITION &&
!TransactionManagerServices.getConfiguration().isAllowMultipleLrc()) {
List<XAResourceHolderState> alwaysLastResources = resources.getByNaturalOrderForPosition(Scheduler.ALWAYS_LAST_POSITION);
if (alwaysLastResources != null && !alwaysLastResources.isEmpty())
throw new BitronixSystemException("cannot enlist more than one non-XA resource, tried enlisting " + xaResourceHolderState + ", already enlisted: " + alwaysLastResources.get(0));
}
xaResourceHolderState.setXid(xid);
xaResourceHolderState.start(flag);
// in case of a JOIN, the resource holder is already in the scheduler -> do not add it twice
if (toBeJoinedHolderState != null) {
resources.remove(toBeJoinedHolderState);
}
// this must be done only after start() successfully returned
resources.add(xaResourceHolderState, xaResourceHolderState.getTwoPcOrderingPosition());
}
/**
* Delist the specified {@link XAResourceHolderState}. A reference to the resource is kept anyway.
* @param xaResourceHolderState the {@link XAResourceHolderState} to be delisted.
* @param flag the delistment flag.
* @return true if the resource could be delisted, false otherwise.
* @throws XAException if the resource threw an exception during delistment.
* @throws BitronixSystemException if an internal error occured.
*/
public boolean delist(XAResourceHolderState xaResourceHolderState, int flag) throws XAException, BitronixSystemException {
if (findXAResourceHolderState(xaResourceHolderState.getXAResource()) != null) {
if (log.isDebugEnabled()) { log.debug("delisting resource " + xaResourceHolderState); }
xaResourceHolderState.end(flag);
return true;
}
log.warn("trying to delist resource that has not been previously enlisted: " + xaResourceHolderState);
return false;
}
/**
* Suspend all enlisted resources from the current transaction context.
* @throws XAException if the resource threw an exception during suspend.
*/
public void suspend() throws XAException {
for (XAResourceHolderState xaResourceHolderState : resources) {
if (!xaResourceHolderState.isEnded()) {
if (log.isDebugEnabled()) { log.debug("suspending " + xaResourceHolderState); }
xaResourceHolderState.end(XAResource.TMSUCCESS);
}
} // while
}
/**
* Resume all enlisted resources in the current transaction context.
* @throws XAException if the resource threw an exception during resume.
*/
public void resume() throws XAException {
// all XAResource needs to be re-enlisted but this must happen
// outside the Scheduler's iteration as enlist() can change the
// collection's content and confuse the iterator.
List<XAResourceHolderState> toBeReEnlisted = new ArrayList<XAResourceHolderState>();
for (XAResourceHolderState xaResourceHolderState : resources) {
if (log.isDebugEnabled()) { log.debug("resuming " + xaResourceHolderState); }
// If a prepared statement is (re-)used after suspend/resume is performed its XAResource needs to be
// re-enlisted. This must be done outside this loop or that will confuse the iterator!
toBeReEnlisted.add(new XAResourceHolderState(xaResourceHolderState));
}
if (toBeReEnlisted.size() > 0 && log.isDebugEnabled()) log.debug("re-enlisting " + toBeReEnlisted.size() + " resource(s)");
for (XAResourceHolderState xaResourceHolderState : toBeReEnlisted) {
if (log.isDebugEnabled()) { log.debug("re-enlisting resource " + xaResourceHolderState); }
try {
enlist(xaResourceHolderState);
xaResourceHolderState.getXAResourceHolder().putXAResourceHolderState(xaResourceHolderState.getXid(), xaResourceHolderState);
} catch (BitronixSystemException ex) {
throw new BitronixXAException("error re-enlisting resource during resume: " + xaResourceHolderState, XAException.XAER_RMERR, ex);
}
}
}
/**
* Look if an {@link XAResource} has already been enlisted.
* @param xaResource the {@link XAResource} to look for.
* @return the {@link XAResourceHolderState} of the enlisted resource or null if the {@link XAResource} has not
* been enlisted in this {@link XAResourceManager}.
* @throws BitronixSystemException if an internal error happens.
*/
public XAResourceHolderState findXAResourceHolderState(XAResource xaResource) throws BitronixSystemException {
for (XAResourceHolderState xaResourceHolderState : resources) {
if (xaResourceHolderState.getXAResource() == xaResource)
return xaResourceHolderState;
}
return null;
}
/**
* Search for an eventually already enlisted {@link XAResourceHolderState} that could be joined with the
* {@link XAResourceHolderState} passed as parameter.<br/>
* If datasource configuration property <code>bitronix.useTmJoin=false</code> is set this method always returns null.
* @param xaResourceHolderState a {@link XAResourceHolderState} looking to be joined.
* @return another enlisted {@link XAResourceHolderState} that can be joined with the one passed in or null if none is found.
* @throws XAException if call to XAResource.isSameRM() fails.
*/
private XAResourceHolderState getManagedResourceWithSameRM(XAResourceHolderState xaResourceHolderState) throws XAException {
if (!xaResourceHolderState.getUseTmJoin()) {
if (log.isDebugEnabled()) { log.debug("join disabled on resource " + xaResourceHolderState); }
return null;
}
for (XAResourceHolderState alreadyEnlistedHolderState : resources) {
if (log.isDebugEnabled())
log.debug("checking joinability of " + xaResourceHolderState + " with " + alreadyEnlistedHolderState);
if (alreadyEnlistedHolderState.isEnded() &&
!alreadyEnlistedHolderState.isSuspended() &&
xaResourceHolderState.getXAResource().isSameRM(alreadyEnlistedHolderState.getXAResource())) {
if (log.isDebugEnabled()) { log.debug("resources are joinable"); }
return alreadyEnlistedHolderState;
}
if (log.isDebugEnabled()) { log.debug("resources are not joinable"); }
}
if (log.isDebugEnabled()) { log.debug("no joinable resource found for " + xaResourceHolderState); }
return null;
}
/**
* Remove this transaction's {@link XAResourceHolderState} from all enlisted
* {@link bitronix.tm.resource.common.XAResourceHolder}s.
*/
public void clearXAResourceHolderStates() {
if (log.isDebugEnabled()) { log.debug("clearing XAResourceHolder states on " + resources.size() + " resource(s)"); }
Iterator<XAResourceHolderState> it = resources.iterator();
while (it.hasNext()) {
XAResourceHolderState xaResourceHolderState = it.next();
XAResourceHolder resourceHolder = xaResourceHolderState.getXAResourceHolder();
// clear out the current state
resourceHolder.removeXAResourceHolderState(xaResourceHolderState.getXid());
boolean stillExists = resourceHolder.isExistXAResourceHolderStatesForGtrid(gtrid);
if (stillExists) log.warn("resource " + resourceHolder + " did not clean up " + resourceHolder.getXAResourceHolderStateCountForGtrid(gtrid) + "transaction states for GTRID [" + gtrid + "]");
else if (log.isDebugEnabled()) { log.debug("resource " + resourceHolder + " cleaned up all transaction states for GTRID [" + gtrid + "]"); }
it.remove();
}
}
/**
* Get a {@link Set} of unique names of all the enlisted {@link XAResourceHolderState}s.
* @return a {@link Set} of unique names of all the enlisted {@link XAResourceHolderState}s.
*/
public Set<String> collectUniqueNames() {
Set<String> names = new HashSet<String>(resources.size());
for (XAResourceHolderState xaResourceHolderState : resources) {
names.add(xaResourceHolderState.getUniqueName());
}
return Collections.unmodifiableSet(names);
}
public SortedSet<Integer> getNaturalOrderPositions() {
return Collections.unmodifiableSortedSet(resources.getNaturalOrderPositions());
}
public SortedSet<Integer> getReverseOrderPositions() {
return Collections.unmodifiableSortedSet(resources.getReverseOrderPositions());
}
public List<XAResourceHolderState> getNaturalOrderResourcesForPosition(Integer position) {
return Collections.unmodifiableList(resources.getByNaturalOrderForPosition(position));
}
public List<XAResourceHolderState> getReverseOrderResourcesForPosition(Integer position) {
return Collections.unmodifiableList(resources.getByReverseOrderForPosition(position));
}
public List<XAResourceHolderState> getAllResources() {
List<XAResourceHolderState> result = new ArrayList<XAResourceHolderState>(resources.size());
for (Integer positionKey : resources.getNaturalOrderPositions()) {
result.addAll(resources.getByNaturalOrderForPosition(positionKey));
}
return Collections.unmodifiableList(result);
}
/**
* Get the enlisted resources count.
* @return the enlisted resources count.
*/
public int size() {
return resources.size();
}
/**
* Get the GTRID of the transaction the {@link XAResourceManager} instance is attached to.
* @return the GTRID of the transaction the {@link XAResourceManager} instance is attached to.
*/
public Uid getGtrid() {
return gtrid;
}
/**
* Return a human-readable representation of this object.
* @return a human-readable representation of this object.
*/
public String toString() {
return "a XAResourceManager with GTRID [" + gtrid + "] and " + resources;
}
}