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* as indicated by the @author tags. See the copyright.txt file in the
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*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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package org.jboss.ejb3.concurrency.impl;
import org.jboss.ejb3.concurrency.spi.LockableComponent;
import org.jboss.logging.Logger;
import javax.ejb.AccessTimeout;
import javax.ejb.ConcurrentAccessTimeoutException;
import javax.ejb.LockType;
import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
/**
* @author Jaikiran Pai
*/
public abstract class ContainerManagedConcurrencyInterceptor
{
/**
* Logger
*/
private static final Logger logger = Logger.getLogger(ContainerManagedConcurrencyInterceptor.class);
/**
* A spec compliant {@link EJBReadWriteLock}
*/
private ReadWriteLock readWriteLock = new EJBReadWriteLock();
protected abstract LockableComponent getLockableComponent();
@AroundInvoke
public Object invoke(InvocationContext invocationContext) throws Exception
{
LockableComponent lockableComponent = this.getLockableComponent();
// get the invoked method
Method invokedMethod = invocationContext.getMethod();
if (invokedMethod == null)
{
throw new IllegalArgumentException("Invocation context: " + invocationContext + " cannot be processed because it's not applicable for a method invocation");
}
// get the Lock applicable for this method
Lock lock = getLock(lockableComponent, invokedMethod);
// the default access timeout (will be used in the absence of any explicit access timeout value for the invoked method)
AccessTimeout defaultAccessTimeout = lockableComponent.getDefaultAccessTimeout();
// set to the default values
long time = defaultAccessTimeout.value();
TimeUnit unit = defaultAccessTimeout.unit();
AccessTimeout accessTimeoutOnMethod = lockableComponent.getAccessTimeout(invokedMethod);
if (accessTimeoutOnMethod != null)
{
if (accessTimeoutOnMethod.value() < 0)
{
// for any negative value of timeout, we just default to max timeout val and max timeout unit.
// violation of spec! But we don't want to wait indefinitely.
logger.debug("Ignoring a negative @AccessTimeout value: " + accessTimeoutOnMethod.value() + " and timeout unit: "
+ accessTimeoutOnMethod.unit().name() + ". Will default to timeout value: " + defaultAccessTimeout.value()
+ " and timeout unit: " + defaultAccessTimeout.unit().name());
}
else
{
// use the explicit access timeout values specified on the method
time = accessTimeoutOnMethod.value();
unit = accessTimeoutOnMethod.unit();
}
}
// try getting the lock
boolean success = lock.tryLock(time, unit);
if (!success)
{
throw new ConcurrentAccessTimeoutException("EJB 3.1 PFD2 4.8.5.5.1 concurrent access timeout on " + invocationContext
+ " - could not obtain lock within " + time + unit.name());
}
try
{
// lock obtained. now proceed!
return invocationContext.proceed();
}
finally
{
lock.unlock();
}
}
private Lock getLock(LockableComponent lockableComponent, Method method)
{
LockType lockType = lockableComponent.getLockType(method);
switch (lockType)
{
case READ:
return readWriteLock.readLock();
case WRITE:
return readWriteLock.writeLock();
}
throw new IllegalStateException("Illegal lock type " + lockType + " on " + method + " for component " + lockableComponent);
}
}