/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.felix.coordinator.impl;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Stack;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.atomic.AtomicLong;
import org.osgi.framework.Bundle;
import org.osgi.service.coordinator.Coordination;
import org.osgi.service.coordinator.CoordinationException;
import org.osgi.service.coordinator.Participant;
/**
* The <code>CoordinationMgr</code> is the actual back-end manager of all
* Coordinations created by the Coordinator implementation.
*/
public class CoordinationMgr
{
private ThreadLocal<Stack<CoordinationImpl>> perThreadStack;
private final AtomicLong ctr;
private final Map<Long, CoordinationImpl> coordinations;
private final Map<Participant, CoordinationImpl> participants;
private final Timer coordinationTimer;
/**
* Wait at most 60 seconds for participant to be eligible for participation
* in a coordination.
*
* @see #singularizeParticipant(Participant, CoordinationImpl)
*/
private long participationTimeOut = 60 * 1000L;
CoordinationMgr()
{
perThreadStack = new ThreadLocal<Stack<CoordinationImpl>>();
ctr = new AtomicLong(-1);
coordinations = new HashMap<Long, CoordinationImpl>();
participants = new IdentityHashMap<Participant, CoordinationImpl>();
coordinationTimer = new Timer("Coordination Timer", true);
}
void cleanUp()
{
// terminate coordination timeout timer
coordinationTimer.purge();
coordinationTimer.cancel();
// terminate all active coordinations
final List<CoordinationImpl> coords = new ArrayList<CoordinationImpl>();
synchronized ( this.coordinations ) {
coords.addAll(this.coordinations.values());
this.coordinations.clear();
}
for(final CoordinationImpl c : coords)
{
if ( !c.isTerminated() )
{
c.fail(Coordination.RELEASED);
}
}
// release all participants
synchronized ( this.participants )
{
participants.clear();
}
// cannot really clear out the thread local but we can let it go
perThreadStack = null;
}
private Stack<CoordinationImpl> getThreadStack(final boolean create)
{
final ThreadLocal<Stack<CoordinationImpl>> tl = this.perThreadStack;
Stack<CoordinationImpl> stack = null;
if ( tl != null )
{
stack = tl.get();
if ( stack == null && create ) {
stack = new Stack<CoordinationImpl>();
tl.set(stack);
}
}
return stack;
}
void configure(final long participationTimeout)
{
this.participationTimeOut = participationTimeout;
}
void schedule(final TimerTask task, final long deadLine)
{
if (deadLine < 0)
{
task.cancel();
}
else
{
coordinationTimer.schedule(task, new Date(deadLine));
}
}
void lockParticipant(final Participant p, final CoordinationImpl c)
{
synchronized (participants)
{
// wait for participant to be released
long completeWaitTime = participationTimeOut;
long cutOff = System.currentTimeMillis() + completeWaitTime;
CoordinationImpl current = participants.get(p);
while (current != null && current != c)
{
final long waitTime = (completeWaitTime > 500) ? 500 : completeWaitTime;
completeWaitTime = completeWaitTime - waitTime;
if (current.getThread() != null && current.getThread() == c.getThread())
{
throw new CoordinationException("Participant " + p + " already participating in Coordination "
+ current.getId() + "/" + current.getName() + " in this thread", c,
CoordinationException.DEADLOCK_DETECTED);
}
try
{
participants.wait(waitTime);
}
catch (InterruptedException ie)
{
throw new CoordinationException("Interrupted waiting to add Participant " + p
+ " currently participating in Coordination " + current.getId() + "/" + current.getName()
+ " in this thread", c, CoordinationException.LOCK_INTERRUPTED);
}
// timeout waiting for participation
if (System.currentTimeMillis() >= cutOff)
{
throw new CoordinationException("Timed out waiting to join coordinaton", c,
CoordinationException.FAILED, Coordination.TIMEOUT);
}
// check again
current = participants.get(p);
}
// lock participant into coordination
participants.put(p, c);
}
}
void releaseParticipant(final Participant p)
{
synchronized (participants)
{
participants.remove(p);
participants.notifyAll();
}
}
// ---------- Coordinator back end implementation
CoordinationImpl create(final CoordinatorImpl owner, final String name, final long timeout)
{
final long id = ctr.incrementAndGet();
final CoordinationImpl c = new CoordinationImpl(owner, id, name, timeout);
synchronized ( this.coordinations )
{
coordinations.put(id, c);
}
return c;
}
void unregister(final CoordinationImpl c, final boolean removeFromThread)
{
synchronized ( this.coordinations )
{
coordinations.remove(c.getId());
}
if ( removeFromThread )
{
final Stack<CoordinationImpl> stack = this.getThreadStack(false);
if (stack != null)
{
stack.remove(c);
}
}
}
void push(final CoordinationImpl c)
{
Stack<CoordinationImpl> stack = this.getThreadStack(true);
if ( stack != null)
{
if ( stack.contains(c) )
{
throw new CoordinationException("Coordination already pushed", c, CoordinationException.ALREADY_PUSHED);
}
c.setAssociatedThread(Thread.currentThread());
stack.push(c);
}
}
Coordination pop()
{
final Stack<CoordinationImpl> stack = this.getThreadStack(false);
if (stack != null && !stack.isEmpty())
{
final CoordinationImpl c = stack.pop();
if ( c != null ) {
c.setAssociatedThread(null);
}
return c;
}
return null;
}
Coordination peek()
{
final Stack<CoordinationImpl> stack = this.getThreadStack(false);
if (stack != null && !stack.isEmpty())
{
return stack.peek();
}
return null;
}
Collection<Coordination> getCoordinations()
{
final ArrayList<Coordination> result = new ArrayList<Coordination>();
synchronized ( this.coordinations )
{
for(final CoordinationImpl c : this.coordinations.values() )
{
result.add(c.getHolder());
}
}
return result;
}
Coordination getCoordinationById(final long id)
{
synchronized ( this.coordinations )
{
final CoordinationImpl c = coordinations.get(id);
return (c == null || c.isTerminated()) ? null : c;
}
}
public Coordination getEnclosingCoordination(final CoordinationImpl c)
{
final Stack<CoordinationImpl> stack = this.getThreadStack(false);
if ( stack != null )
{
final int index = stack.indexOf(c);
if ( index > 0 )
{
return stack.elementAt(index - 1);
}
}
return null;
}
public CoordinationException endNestedCoordinations(final CoordinationImpl c)
{
CoordinationException partiallyFailed = null;
final Stack<CoordinationImpl> stack = this.getThreadStack(false);
if ( stack != null )
{
final int index = stack.indexOf(c) + 1;
if ( index > 0 && stack.size() > index )
{
final int count = stack.size()-index;
for(int i=0;i<count;i++)
{
final CoordinationImpl nested = stack.pop();
try
{
if ( partiallyFailed != null)
{
nested.fail(partiallyFailed);
}
nested.end();
}
catch ( final CoordinationException ce)
{
partiallyFailed = ce;
}
}
}
}
return partiallyFailed;
}
/**
* Dispose all coordinations for that bundle
* @param owner The owner bundle
*/
public void dispose(final Bundle owner) {
final List<CoordinationImpl> candidates = new ArrayList<CoordinationImpl>();
synchronized ( this.coordinations )
{
final Iterator<Map.Entry<Long, CoordinationImpl>> iter = this.coordinations.entrySet().iterator();
while ( iter.hasNext() )
{
final Map.Entry<Long, CoordinationImpl> entry = iter.next();
final CoordinationImpl c = entry.getValue();
if ( c.getBundle().getBundleId() == owner.getBundleId() )
{
candidates.add(c);
}
}
}
if ( candidates.size() > 0 )
{
for(final CoordinationImpl c : candidates)
{
if ( !c.isTerminated() )
{
c.fail(Coordination.RELEASED);
}
else
{
this.unregister(c, true);
}
}
}
}
}