/*
* 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.resource;
import bitronix.tm.TransactionManagerServices;
import bitronix.tm.recovery.IncrementalRecoverer;
import bitronix.tm.recovery.RecoveryException;
import bitronix.tm.resource.common.XAResourceHolder;
import bitronix.tm.resource.common.XAResourceProducer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.transaction.xa.XAResource;
import java.io.UnsupportedEncodingException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
/**
* Collection of initialized {@link XAResourceProducer}s. All resources must be registered in the {@link ResourceRegistrar}
* before they can be used by the transaction manager.
* <p/>
* Note: The implementation is based on a thread safe, read-optimized list (copy-on-write) assuming that the
* number of registered resources is around 1 to 16 entries and does not change often. If this assumption is
* not-true it may be required to re-implement this with a ConcurrentMap instead.
*
* @author Ludovic Orban
* @author Juergen Kellerer
*/
public final class ResourceRegistrar {
private final static Logger log = LoggerFactory.getLogger(ResourceRegistrar.class);
/**
* Specifies the charset that unique names of resources must be encodable with to be storeable in a TX journal.
*/
public final static String UNIQUE_NAME_CHARSET = "US-ASCII";
private final static Set<ProducerHolder> resources = new CopyOnWriteArraySet<ProducerHolder>();
/**
* Get a registered {@link XAResourceProducer}.
*
* @param uniqueName the name of the recoverable resource producer.
* @return the {@link XAResourceProducer} or null if there was none registered under that name.
*/
public static XAResourceProducer get(final String uniqueName) {
if (uniqueName != null) {
for (ProducerHolder holder : resources) {
if (!holder.isInitialized())
continue;
if (uniqueName.equals(holder.getUniqueName()))
return holder.producer;
}
}
return null;
}
/**
* Get all {@link XAResourceProducer}s unique names.
* @return a Set containing all {@link bitronix.tm.resource.common.XAResourceProducer}s unique names.
*/
public static Set<String> getResourcesUniqueNames() {
final Set<String> names = new HashSet<String>(resources.size());
for (ProducerHolder holder : resources) {
if (!holder.isInitialized())
continue;
names.add(holder.getUniqueName());
}
return Collections.unmodifiableSet(names);
}
/**
* Register a {@link XAResourceProducer}. If registration happens after the transaction manager started, incremental
* recovery is run on that resource.
* @param producer the {@link XAResourceProducer}.
* @throws RecoveryException When an error happens during recovery.
*/
public static void register(XAResourceProducer producer) throws RecoveryException {
try {
final boolean alreadyRunning = TransactionManagerServices.isTransactionManagerRunning();
final ProducerHolder holder = alreadyRunning ? new InitializableProducerHolder(producer) : new ProducerHolder(producer);
if (resources.add(holder)) {
if (holder instanceof InitializableProducerHolder) {
boolean recovered = false;
try {
if (log.isDebugEnabled()) { log.debug("Transaction manager is running, recovering resource '" + holder.getUniqueName() + "'."); }
IncrementalRecoverer.recover(producer);
((InitializableProducerHolder) holder).initialize();
recovered = true;
} finally {
if (!recovered) { resources.remove(holder); }
}
}
} else {
throw new IllegalStateException("A resource with uniqueName '" + holder.getUniqueName() + "' has already been registered. " +
"Cannot register XAResourceProducer '" + producer + "'.");
}
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException("Cannot register the XAResourceProducer '" + producer + "' caused by invalid input.", e);
}
}
/**
* Unregister a previously registered {@link XAResourceProducer}.
* @param producer the {@link XAResourceProducer}.
*/
public static void unregister(XAResourceProducer producer) {
final ProducerHolder holder = new ProducerHolder(producer);
if (!resources.remove(holder)) {
if (log.isDebugEnabled()) { log.debug("resource with uniqueName '{}' has not been registered", holder.getUniqueName()); }
}
}
/**
* Find in the registered {@link XAResourceProducer}s the {@link XAResourceHolder} from which the specified {@link XAResource} comes from.
*
* @param xaResource the {@link XAResource} to look for
* @return the associated {@link XAResourceHolder} or null if it cannot be found.
*/
public static XAResourceHolder findXAResourceHolder(XAResource xaResource) {
final boolean debug = log.isDebugEnabled();
for (ProducerHolder holder : resources) {
if (!holder.isInitialized())
continue;
final XAResourceProducer producer = holder.producer;
final XAResourceHolder resourceHolder = producer.findXAResourceHolder(xaResource);
if (resourceHolder != null) {
if (debug) { log.debug("XAResource " + xaResource + " belongs to " + resourceHolder + " that itself belongs to " + producer); }
return resourceHolder;
}
if (debug) { log.debug("XAResource " + xaResource + " does not belong to any resource of " + producer); }
}
return null;
}
private ResourceRegistrar() {
}
/**
* Implements a holder that maintains XAResourceProducers in a set only differentiating them by their unique names.
*/
private static class ProducerHolder {
private final XAResourceProducer producer;
private ProducerHolder(XAResourceProducer producer) {
if (producer == null)
throw new IllegalArgumentException("XAResourceProducer may not be 'null'. Verify your call to ResourceRegistrar.[un]register(...).");
final String uniqueName = producer.getUniqueName();
if (uniqueName == null || uniqueName.length() == 0)
throw new IllegalArgumentException("The given XAResourceProducer '" + producer + "' does not specify a uniqueName.");
try {
final String transcodedUniqueName = new String(uniqueName.getBytes(UNIQUE_NAME_CHARSET), UNIQUE_NAME_CHARSET);
if (!transcodedUniqueName.equals(uniqueName)) {
throw new IllegalArgumentException("The given XAResourceProducer's uniqueName '" + uniqueName + "' is not compatible with the charset " +
"'US-ASCII' (transcoding results in '" + transcodedUniqueName + "'). " + System.getProperty("line.separator") +
"BTM requires unique names to be compatible with US-ASCII when used with a transaction journal.");
}
} catch (UnsupportedEncodingException e) {
log.error(UNIQUE_NAME_CHARSET + " encoding character set not found", e);
}
this.producer = producer;
}
boolean isInitialized() {
return true;
}
String getUniqueName() {
return producer.getUniqueName();
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof ProducerHolder)) return false;
ProducerHolder that = (ProducerHolder) o;
return getUniqueName().equals(that.getUniqueName());
}
@Override
public int hashCode() {
return getUniqueName().hashCode();
}
@Override
public String toString() {
return "ProducerHolder{" +
"producer=" + producer +
", initialized=" + isInitialized() +
'}';
}
}
/**
* Extends the default holder with thread safe initialization to put uninitialized holders in the set.
*/
private static class InitializableProducerHolder extends ProducerHolder {
private volatile boolean initialized;
private InitializableProducerHolder(XAResourceProducer producer) {
super(producer);
}
boolean isInitialized() {
return initialized;
}
void initialize() {
initialized = true;
}
}
}