org.jgroups.protocols.Locking Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including
all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and
Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
package org.jgroups.protocols;
import org.jgroups.*;
import org.jgroups.annotations.MBean;
import org.jgroups.annotations.ManagedAttribute;
import org.jgroups.annotations.ManagedOperation;
import org.jgroups.annotations.Property;
import org.jgroups.blocks.locking.AwaitInfo;
import org.jgroups.blocks.locking.LockInfo;
import org.jgroups.blocks.locking.LockNotification;
import org.jgroups.stack.Protocol;
import org.jgroups.util.Bits;
import org.jgroups.util.Owner;
import org.jgroups.util.Streamable;
import org.jgroups.util.Util;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.*;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.LockSupport;
import java.util.concurrent.locks.ReentrantLock;
/**
* Base locking protocol, handling most of the protocol communication with other instances. To use distributed locking,
* {@link org.jgroups.blocks.locking.LockService} is placed on a channel. LockService talks to a subclass of Locking
* via events.
* @author Bela Ban
* @since 2.12
* @see org.jgroups.protocols.CENTRAL_LOCK
*/
@MBean(description="Based class for locking functionality")
abstract public class Locking extends Protocol {
@Property(description="bypasses message bundling if set")
protected boolean bypass_bundling=true;
@Property(description="Number of locks to be used for lock striping (for synchronized access to the server_lock entries)")
protected int lock_striping_size=10;
protected Address local_addr;
protected View view;
// server side locks
protected final ConcurrentMap server_locks=Util.createConcurrentMap(20);
// protected access to the same locks in server_locks
protected Lock[] lock_stripes;
// client side locks
protected final ClientLockTable client_lock_table=new ClientLockTable();
protected final Set lock_listeners=new CopyOnWriteArraySet<>();
protected final static AtomicInteger current_lock_id=new AtomicInteger(1);
protected static enum Type {
GRANT_LOCK, // request to acquire a lock
LOCK_GRANTED, // response to sender of GRANT_LOCK on succcessful lock acquisition
LOCK_DENIED, // response to sender of GRANT_LOCK on unsuccessful lock acquisition (e.g. on tryLock())
RELEASE_LOCK, // request to release a lock
CREATE_LOCK, // request to create a server lock (sent by coordinator to backups). Used by CentralLockService
DELETE_LOCK, // request to delete a server lock (sent by coordinator to backups). Used by CentralLockService
LOCK_AWAIT, // request to await until condition is signaled
COND_SIG, // request to signal awaiting thread
COND_SIG_ALL, // request to signal all awaiting threads
SIG_RET, // response to alert of signal
DELETE_LOCK_AWAIT, // request to delete a waiter
CREATE_AWAITER, // request to create a server lock await (sent by coordinator to backups). Used by CentralLockService
DELETE_AWAITER // request to delete a server lock await (sent by coordinator to backups). Used by CentralLockService
}
public Locking() {
}
public boolean getBypassBundling() {
return bypass_bundling;
}
public void setBypassBundling(boolean bypass_bundling) {
this.bypass_bundling=bypass_bundling;
}
public void addLockListener(LockNotification listener) {
if(listener != null)
lock_listeners.add(listener);
}
public void removeLockListener(LockNotification listener) {
if(listener != null)
lock_listeners.remove(listener);
}
@ManagedAttribute
public String getAddress() {
return local_addr != null? local_addr.toString() : null;
}
@ManagedAttribute
public String getView() {
return view != null? view.toString() : null;
}
public void init() throws Exception {
super.init();
lock_stripes=new Lock[lock_striping_size];
for(int i=0; i < lock_stripes.length; i++)
lock_stripes[i]=new ReentrantLock();
}
public Object down(Event evt) {
switch(evt.getType()) {
case Event.LOCK:
LockInfo info=(LockInfo)evt.getArg();
ClientLock lock=getLock(info.getName());
if(!info.isTrylock()) {
if(info.isLockInterruptibly()) {
try {
lock.lockInterruptibly();
}
catch(InterruptedException e) {
Thread.currentThread().interrupt(); // has to be checked by caller who has to rethrow ...
}
}
else
lock.lock();
}
else {
if(info.isUseTimeout()) {
try {
return lock.tryLock(info.getTimeout(), info.getTimeUnit());
}
catch(InterruptedException e) {
Thread.currentThread().interrupt();
}
}
else
return lock.tryLock();
}
return null;
case Event.UNLOCK:
info=(LockInfo)evt.getArg();
lock=getLock(info.getName(), false);
if(lock != null)
lock.unlock();
return null;
case Event.UNLOCK_ALL:
unlockAll();
return null;
case Event.LOCK_AWAIT:
info=(LockInfo)evt.getArg();
lock=getLock(info.getName(), false);
if (lock == null || !lock.acquired) {
throw new IllegalMonitorStateException();
}
Condition condition = lock.newCondition();
if (info.isUseTimeout()) {
try {
return condition.awaitNanos(info.getTimeUnit().toNanos(info.getTimeout()));
}
catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
else if (info.isLockInterruptibly()) {
try {
condition.await();
}
catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
else {
condition.awaitUninterruptibly();
}
return null;
case Event.LOCK_SIGNAL:
AwaitInfo awaitInfo = (AwaitInfo)evt.getArg();
lock=getLock(awaitInfo.getName(), false);
if (lock == null || !lock.acquired) {
throw new IllegalMonitorStateException();
}
sendSignalConditionRequest(awaitInfo.getName(), awaitInfo.isAll());
return null;
case Event.SET_LOCAL_ADDRESS:
local_addr=(Address)evt.getArg();
break;
case Event.VIEW_CHANGE:
handleView((View)evt.getArg());
break;
}
return down_prot.down(evt);
}
public Object up(Event evt) {
switch(evt.getType()) {
case Event.MSG:
Message msg=(Message)evt.getArg();
LockingHeader hdr=(LockingHeader)msg.getHeader(id);
if(hdr == null)
break;
Request req=(Request)msg.getObject();
log.trace("[%s] <-- [%s] %s", local_addr, msg.getSrc(), req);
switch(req.type) {
case GRANT_LOCK:
case RELEASE_LOCK:
handleLockRequest(req);
break;
case LOCK_GRANTED:
handleLockGrantedResponse(req.lock_name, req.lock_id, req.owner);
break;
case LOCK_DENIED:
handleLockDeniedResponse(req.lock_name, req.lock_id, req.owner);
break;
case CREATE_LOCK:
handleCreateLockRequest(req.lock_name, req.owner);
break;
case DELETE_LOCK:
handleDeleteLockRequest(req.lock_name);
break;
case COND_SIG:
case COND_SIG_ALL:
handleSignalRequest(req);
break;
case LOCK_AWAIT:
handleAwaitRequest(req.lock_name, req.owner);
handleLockRequest(req);
break;
case DELETE_LOCK_AWAIT:
handleDeleteAwaitRequest(req.lock_name, req.owner);
break;
case SIG_RET:
handleSignalResponse(req.lock_name, req.owner);
break;
case CREATE_AWAITER:
handleCreateAwaitingRequest(req.lock_name, req.owner);
break;
case DELETE_AWAITER:
handleDeleteAwaitingRequest(req.lock_name, req.owner);
break;
default:
log.error("Request of type %s not known", req.type);
break;
}
return null;
case Event.VIEW_CHANGE:
handleView((View)evt.getArg());
break;
}
return up_prot.up(evt);
}
protected ClientLock getLock(String name) {
return client_lock_table.getLock(name,getOwner(),true);
}
protected ClientLock getLock(String name, boolean create_if_absent) {
return client_lock_table.getLock(name,getOwner(),create_if_absent);
}
@ManagedOperation(description="Unlocks all currently held locks")
public void unlockAll() {
client_lock_table.unlockAll();
}
@ManagedOperation(description="Dumps all locks")
public String printLocks() {
StringBuilder sb=new StringBuilder();
sb.append("server locks:\n");
for(Map.Entry entry: server_locks.entrySet())
sb.append(entry.getKey()).append(": ").append(entry.getValue()).append("\n");
sb.append("\nmy locks: ").append(client_lock_table.toString());
return sb.toString();
}
protected void handleView(View view) {
this.view=view;
log.debug("view=%s", view);
List members=view.getMembers();
List responses=new ArrayList<>();
for(Map.Entry entry: server_locks.entrySet()) {
String lock_name=entry.getKey();
ServerLock server_lock=entry.getValue();
Lock lock=_getLock(lock_name);
lock.lock();
try {
Response rsp=server_lock.handleView(members);
if(rsp != null)
responses.add(rsp);
if(server_lock.isEmpty() && server_lock.current_owner == null && server_lock.condition.queue.isEmpty())
server_locks.remove(lock_name);
}
finally {
lock.unlock();
}
}
// do the sending outside the lock scope (might block on credits or TCP send)
for(Response rsp: responses)
sendLockResponse(rsp.type, rsp.owner, rsp.lock_name, rsp.lock_id);
}
protected ClientLock createLock(String lock_name, Owner owner) {
return new ClientLock(lock_name, owner);
}
/** Gets a lock from locks based on the hash of the lock name */
protected Lock _getLock(String lock_name) {
int index=lock_name != null? Math.abs(lock_name.hashCode() % lock_stripes.length) : 0;
return lock_stripes[index];
}
protected Owner getOwner() {
return new Owner(local_addr, Thread.currentThread().getId());
}
abstract protected void sendGrantLockRequest(String lock_name, int lock_id, Owner owner, long timeout, boolean is_trylock);
abstract protected void sendReleaseLockRequest(String lock_name, Owner owner);
abstract protected void sendAwaitConditionRequest(String lock_name, Owner owner);
abstract protected void sendSignalConditionRequest(String lock_name, boolean all);
abstract protected void sendDeleteAwaitConditionRequest(String lock_name, Owner owner);
protected void sendRequest(Address dest, Type type, String lock_name, Owner owner, long timeout, boolean is_trylock) {
send(dest, new Request(type, lock_name, owner, timeout, is_trylock));
}
protected void sendRequest(Address dest, Type type, String lock_name, int lock_id, Owner owner, long timeout, boolean is_trylock) {
send(dest, new Request(type, lock_name, owner, timeout, is_trylock).lockId(lock_id));
}
protected void sendLockResponse(Type type, Owner dest, String lock_name, int lock_id) {
send(dest.getAddress(), new Request(type, lock_name, dest, 0).lockId(lock_id));
}
protected void sendSignalResponse(Owner dest, String lock_name) {
send(dest.getAddress(), new Request(Type.SIG_RET, lock_name, dest, 0));
}
protected void send(Address dest, Request req) {
// Message msg=new Message(dest, req).putHeader(id, new LockingHeader()).setFlag(Message.Flag.OOB);
Message msg=new Message(dest, req).putHeader(id, new LockingHeader());
if(bypass_bundling)
msg.setFlag(Message.Flag.DONT_BUNDLE);
log.trace("[%s] --> %s] %s", local_addr, dest == null? "ALL" : dest, req);
try {
down_prot.down(new Event(Event.MSG, msg));
}
catch(Exception ex) {
log.error("failed sending %s request: %s", req.type, ex);
}
}
protected void handleLockRequest(Request req) {
Response rsp=null;
Lock lock=_getLock(req.lock_name);
lock.lock();
try {
ServerLock server_lock=server_locks.get(req.lock_name);
if(server_lock == null) {
server_lock=new ServerLock(req.lock_name);
ServerLock tmp=server_locks.putIfAbsent(req.lock_name, server_lock);
if(tmp != null)
server_lock=tmp;
else
notifyLockCreated(req.lock_name);
}
rsp=server_lock.handleRequest(req);
if(server_lock.isEmpty() && server_lock.current_owner == null && server_lock.condition.queue.isEmpty())
server_locks.remove(req.lock_name);
}
finally {
lock.unlock();
}
// moved outside the lock scope
if(rsp != null)
sendLockResponse(rsp.type, rsp.owner, rsp.lock_name, rsp.lock_id);
}
protected void handleLockGrantedResponse(String lock_name, int lock_id, Owner owner) {
ClientLock lock=client_lock_table.getLock(lock_name,owner,false);
if(lock != null)
lock.handleLockGrantedResponse(lock_id);
}
protected void handleLockDeniedResponse(String lock_name, int lock_id, Owner owner) {
ClientLock lock=client_lock_table.getLock(lock_name,owner,false);
if(lock != null)
lock.lockDenied(lock_id);
}
protected void handleAwaitRequest(String lock_name, Owner owner) {
Lock lock=_getLock(lock_name);
lock.lock();
try {
ServerLock server_lock=server_locks.get(lock_name);
if (server_lock != null)
server_lock.condition.addWaiter(owner);
else
log.error("Condition await was received but lock was not created. Waiter may block forever");
}
finally {
lock.unlock();
}
}
protected void handleDeleteAwaitRequest(String lock_name, Owner owner) {
Lock lock=_getLock(lock_name);
lock.lock();
try {
ServerLock server_lock=server_locks.get(lock_name);
if (server_lock != null)
server_lock.condition.removeWaiter(owner);
else
log.error("Condition await delete was received, but lock was gone");
}
finally {
lock.unlock();
}
}
protected void handleSignalResponse(String lock_name, Owner owner) {
ClientLock lock=client_lock_table.getLock(lock_name,owner,false);
if(lock != null) {
lock.condition.signaled();
}
else {
log.error("Condition response was client lock was not present. Ignored signal.");
}
}
protected void handleSignalRequest(Request req) {
Response rsp=null;
Lock lock=_getLock(req.lock_name);
lock.lock();
try {
ServerLock server_lock=server_locks.get(req.lock_name);
if (server_lock != null)
rsp=server_lock.handleRequest(req);
else
log.error("Condition signal was received but lock was not created. Couldn't notify anyone.");
}
finally {
lock.unlock();
}
// moved outside the lock scope
if(rsp != null)
sendLockResponse(rsp.type, rsp.owner, rsp.lock_name, rsp.lock_id);
}
protected void handleCreateLockRequest(String lock_name, Owner owner) {
Lock lock=_getLock(lock_name);
lock.lock();
try {
server_locks.put(lock_name, new ServerLock(lock_name, owner));
}
finally {
lock.unlock();
}
}
protected void handleDeleteLockRequest(String lock_name) {
Lock lock=_getLock(lock_name);
lock.lock();
try {
ServerLock server_lock = server_locks.get(lock_name);
if(server_lock == null)
return;
if (server_lock.condition.queue.isEmpty())
server_locks.remove(lock_name);
else
server_lock.current_owner = null;
}
finally {
lock.unlock();
}
}
protected void handleCreateAwaitingRequest(String lock_name, Owner owner) {
Lock lock=_getLock(lock_name);
lock.lock();
try {
ServerLock server_lock = server_locks.get(lock_name);
if (server_lock == null) {
server_lock = new ServerLock(lock_name);
ServerLock tmp=server_locks.putIfAbsent(lock_name,server_lock);
if(tmp != null)
server_lock=tmp;
}
server_lock.condition.queue.add(owner);
}
finally {
lock.unlock();
}
}
protected void handleDeleteAwaitingRequest(String lock_name, Owner owner) {
Lock lock=_getLock(lock_name);
lock.lock();
try {
ServerLock server_lock = server_locks.get(lock_name);
if (server_lock != null) {
server_lock.condition.queue.remove(owner);
if (server_lock.condition.queue.isEmpty() && server_lock.current_owner == null) {
server_locks.remove(lock_name);
}
}
}
finally {
lock.unlock();
}
}
protected void notifyLockCreated(String lock_name) {
for(LockNotification listener: lock_listeners) {
try {
listener.lockCreated(lock_name);
}
catch(Throwable t) {
log.error("failed notifying %s: %s", listener, t.toString());
}
}
}
protected void notifyLockDeleted(String lock_name) {
for(LockNotification listener: lock_listeners) {
try {
listener.lockDeleted(lock_name);
}
catch(Throwable t) {
log.error("failed notifying %s: %s", listener, t.toString());
}
}
}
protected void notifyLocked(String lock_name, Owner owner) {
for(LockNotification listener: lock_listeners) {
try {
listener.locked(lock_name,owner);
}
catch(Throwable t) {
log.error("failed notifying %s: %s", listener, t.toString());
}
}
}
protected void notifyUnlocked(String lock_name, Owner owner) {
for(LockNotification listener: lock_listeners) {
try {
listener.unlocked(lock_name,owner);
}
catch(Throwable t) {
log.error("failed notifying %s: %s", listener, t.toString());
}
}
}
protected void notifyAwaiting(String lock_name, Owner owner) {
for(LockNotification listener: lock_listeners) {
try {
listener.awaiting(lock_name,owner);
}
catch(Throwable t) {
log.error("failed notifying %s: %s", listener, t.toString());
}
}
}
protected void notifyAwaited(String lock_name, Owner owner) {
for(LockNotification listener: lock_listeners) {
try {
listener.awaited(lock_name,owner);
}
catch(Throwable t) {
log.error("failed notifying %s: %s", listener, t.toString());
}
}
}
/**
* Server side queue for handling of lock requests (lock, release).
* @author Bela Ban
*/
protected class ServerLock {
protected final String lock_name;
protected Owner current_owner;
protected final List queue=new ArrayList<>();
protected final ServerCondition condition;
public ServerLock(String lock_name) {
this.lock_name=lock_name;
this.condition=new ServerCondition(this);
}
protected ServerLock(String lock_name, Owner owner) {
this.lock_name=lock_name;
this.current_owner=owner;
this.condition=new ServerCondition(this);
}
protected Response handleRequest(Request req) {
switch(req.type) {
case GRANT_LOCK:
if(current_owner == null) {
setOwner(req.owner);
return new Response(Type.LOCK_GRANTED, req.owner, req.lock_name, req.lock_id);
}
if(current_owner.equals(req.owner))
return new Response(Type.LOCK_GRANTED, req.owner, req.lock_name, req.lock_id);
if(req.is_trylock && req.timeout <= 0)
return new Response(Type.LOCK_DENIED, req.owner, req.lock_name, req.lock_id);
addToQueue(req);
break;
case RELEASE_LOCK:
case LOCK_AWAIT:
if(current_owner == null)
break;
if(current_owner.equals(req.owner))
setOwner(null);
else
addToQueue(req);
break;
case COND_SIG:
condition.signal(false);
break;
case COND_SIG_ALL:
condition.signal(true);
break;
default:
throw new IllegalArgumentException("type " + req.type + " is invalid here");
}
return processQueue();
}
protected Response handleView(List members) {
if(current_owner != null && !members.contains(current_owner.getAddress())) {
Owner tmp=current_owner;
setOwner(null);
log.debug("unlocked \"%s\" because owner %s left", lock_name, tmp);
}
synchronized(queue) {
for(Iterator it=queue.iterator(); it.hasNext(); ) {
Request req=it.next();
if(!members.contains(req.owner.getAddress()))
it.remove();
}
}
for(Iterator it=condition.queue.iterator(); it.hasNext();) {
Owner own=it.next();
if(!members.contains(own.getAddress()))
it.remove();
}
return processQueue();
}
protected void addToQueue(Request req) {
synchronized(queue) {
if(queue.isEmpty()) {
if(req.type == Type.GRANT_LOCK)
queue.add(req);
return; // RELEASE_LOCK is discarded on an empty queue
}
}
// at this point the queue is not empty
switch(req.type) {
// If there is already a lock request from the same owner, discard the new lock request
case GRANT_LOCK:
synchronized(queue) {
if(!isRequestPresent(Type.GRANT_LOCK, req.owner))
queue.add(req);
}
break;
case RELEASE_LOCK:
// Release the lock request from the same owner already in the queue
// If there is no lock request, discard the unlock request
removeRequest(Type.GRANT_LOCK, req.owner);
break;
}
}
/** Checks if a certain request from a given owner is already in the queue */
protected boolean isRequestPresent(Type type, Owner owner) { // holds lock on queue
for(Request req: queue)
if(req.type == type && req.owner.equals(owner))
return true;
return false;
}
protected void removeRequest(Type type, Owner owner) {
synchronized(queue) {
for(Iterator it=queue.iterator(); it.hasNext(); ) {
Request req=it.next();
if(req.type == type && req.owner.equals(owner))
it.remove();
}
}
}
protected Request getNextRequest() {
synchronized(queue) {
return !queue.isEmpty()? queue.remove(0) : null;
}
}
protected Response processQueue() {
if(current_owner != null)
return null;
Request req;
while((req=getNextRequest()) != null) {
if(req.type == Type.GRANT_LOCK) {
setOwner(req.owner);
return new Response(Type.LOCK_GRANTED, req.owner, req.lock_name, req.lock_id);
}
}
return null;
}
protected void setOwner(Owner owner) {
if(owner == null) {
if(current_owner != null) {
Owner tmp=current_owner;
current_owner=null;
notifyUnlocked(lock_name, tmp);
}
}
else {
current_owner=owner;
notifyLocked(lock_name, owner);
}
}
public boolean isEmpty() {
synchronized(queue) {
return queue.isEmpty();
}
}
public String toString() {
StringBuilder sb=new StringBuilder();
sb.append(current_owner);
synchronized(queue) {
if(!queue.isEmpty()) {
sb.append(", queue: ");
for(Request req : queue) {
sb.append(req.toStringShort()).append(" ");
}
}
}
return sb.toString();
}
}
protected class ServerCondition {
protected final ServerLock lock;
protected final Queue queue=new ArrayDeque<>();
public ServerCondition(ServerLock lock) {
this.lock = lock;
}
public void addWaiter(Owner waiter) {
notifyAwaiting(lock.lock_name, waiter);
log.trace("Waiter [%s] was added for %s", waiter, lock.lock_name);
queue.add(waiter);
}
public void removeWaiter(Owner waiter) {
notifyAwaited(lock.lock_name, waiter);
log.trace("Waiter [%s] was removed for %s", waiter, lock.lock_name);
queue.remove(waiter);
}
public void signal(boolean all) {
if (queue.isEmpty())
log.trace("Signal for [%s] ignored since, no one is waiting in queue", lock.lock_name);
Owner entry;
if (all) {
while ((entry = queue.poll()) != null) {
notifyAwaited(lock.lock_name, entry);
log.trace("Signalled %s for %s", entry, lock.lock_name);
sendSignalResponse(entry, lock.lock_name);
}
}
else {
entry = queue.poll();
if (entry != null) {
notifyAwaited(lock.lock_name, entry);
log.trace("Signalled %s for %s", entry, lock.lock_name);
sendSignalResponse(entry, lock.lock_name);
}
}
}
}
/**
* Implementation of {@link Lock}. This is a client stub communicates with a server equivalent. The semantics are
* more or less those of {@link Lock}, but may differ slightly.
* For details see {@link org.jgroups.blocks.locking.LockService}.
*/
protected class ClientLock implements Lock {
protected final String name;
protected Owner owner;
protected volatile boolean acquired;
protected volatile boolean denied;
protected volatile boolean is_trylock;
protected long timeout;
protected final ClientCondition condition;
// unique for locks for the same name:owner, can wrap around (that's ok)
protected final int lock_id=current_lock_id.getAndIncrement();
public ClientLock(String name) {
this.name=name;
this.condition = new ClientCondition(this);
}
public ClientLock(String name, Owner owner) {
this(name);
this.owner=owner;
}
public void lock() {
try {
acquire(false);
}
catch(InterruptedException e) { // should never happen
Thread.currentThread().interrupt(); // just a second line of defense
}
}
public void lockInterruptibly() throws InterruptedException {
acquire(true);
}
public boolean tryLock() {
try {
return acquireTryLock(0, false);
}
catch(InterruptedException e) {
Thread.currentThread().interrupt();
return false;
}
}
public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
return acquireTryLock(TimeUnit.MILLISECONDS.convert(time, unit), true);
}
public synchronized void unlock() {
_unlock(false);
}
public Condition newCondition() {
// Currently only 1 condition per Lock is supported
return condition;
}
public String toString() {
return name + " (id=" + lock_id + ", locked=" + acquired + ")";
}
protected synchronized void lockGranted(int lock_id) {
if(this.lock_id != lock_id) {
log.error("discarded LOCK-GRANTED response with lock-id=" + lock_id + ", my lock-id=" + this.lock_id);
return;
}
acquired=true;
this.notifyAll();
}
protected synchronized void lockDenied(int lock_id) {
if(this.lock_id != lock_id) {
log.error("discarded LOCK-DENIED response with lock-id=" + lock_id + ", my lock_id=" + this.lock_id);
return;
}
denied=true;
this.notifyAll();
}
protected void handleLockGrantedResponse(int lock_id) {
lockGranted(lock_id);
}
protected synchronized void acquire(boolean throwInterrupt) throws InterruptedException {
if(acquired)
return;
if(throwInterrupt && Thread.interrupted())
throw new InterruptedException();
owner=getOwner();
sendGrantLockRequest(name, lock_id, owner, 0, false);
boolean interrupted=false;
while(!acquired) {
try {
this.wait();
}
catch(InterruptedException e) {
if(throwInterrupt && !acquired) {
_unlock(true);
throw e;
}
// If we don't throw exceptions then we just set the interrupt flag and let it loop around
interrupted=true;
}
}
if(interrupted)
Thread.currentThread().interrupt();
}
protected synchronized void _unlock(boolean force) {
if(!acquired && !denied && !force)
return;
this.timeout=0;
this.is_trylock=false;
if(!denied)
sendReleaseLockRequest(name, owner);
acquired=denied=false;
notifyAll();
client_lock_table.removeClientLock(name,owner);
notifyLockDeleted(name);
owner=null;
}
protected synchronized boolean acquireTryLock(long timeout, boolean use_timeout) throws InterruptedException {
if(denied)
return false;
if(!acquired) {
if(use_timeout && Thread.interrupted())
throw new InterruptedException();
is_trylock=true;
this.timeout=timeout;
if(owner == null)
owner=getOwner();
sendGrantLockRequest(name, lock_id, owner, timeout, true);
boolean interrupted = false;
while(!acquired && !denied) {
if(use_timeout) {
long timeout_ns=TimeUnit.NANOSECONDS.convert(timeout, TimeUnit.MILLISECONDS),
wait_time=timeout_ns,
start=System.nanoTime();
while(wait_time > 0 && !acquired && !denied) {
try {
long wait_ms=TimeUnit.MILLISECONDS.convert(wait_time, TimeUnit.NANOSECONDS);
if(wait_ms <= 0)
break;
this.wait(wait_ms);
}
catch(InterruptedException e) {
interrupted=true;
}
finally {
wait_time=timeout_ns - (System.nanoTime() - start);
this.timeout=TimeUnit.MILLISECONDS.convert(wait_time, TimeUnit.NANOSECONDS);
}
}
break;
}
else {
try {
this.wait();
}
catch(InterruptedException e) {
interrupted = true;
}
}
}
if(interrupted)
Thread.currentThread().interrupt();
}
boolean retval=acquired && !denied;
if(!acquired || denied)
_unlock(true);
return retval;
}
}
/** Manages access to client locks */
protected class ClientLockTable {
protected final ConcurrentMap> table=Util.createConcurrentMap(20);
protected synchronized ClientLock getLock(String name, Owner owner, boolean create_if_absent) {
Map owners=table.get(name);
if(owners == null) {
if(!create_if_absent)
return null;
owners=new HashMap<>();
Map existing=table.putIfAbsent(name,owners);
if(existing != null)
owners=existing;
}
ClientLock lock=owners.get(owner);
if(lock == null) {
if(!create_if_absent)
return null;
lock=createLock(name, owner);
owners.put(owner, lock);
}
return lock;
}
protected synchronized void removeClientLock(String lock_name, Owner owner) {
Map owners=table.get(lock_name);
if(owners != null) {
ClientLock lock=owners.remove(owner);
if(lock != null) {
if(owners.isEmpty())
table.remove(lock_name);
}
}
}
protected void unlockAll() {
List lock_list=new ArrayList<>();
synchronized(this) {
Collection> maps=table.values();
for(Map map: maps)
lock_list.addAll(map.values());
}
for(ClientLock lock: lock_list)
lock.unlock();
}
protected void resendPendingLockRequests() {
if(!table.isEmpty()) {
for(Map map: table.values()) {
for(ClientLock lock: map.values()) {
if(!lock.acquired && !lock.denied)
sendGrantLockRequest(lock.name, lock.lock_id, lock.owner, lock.timeout, lock.is_trylock);
}
}
}
}
protected synchronized Collection> values() {
return table.values();
}
public String toString() {
StringBuilder sb=new StringBuilder();
boolean first_element=true;
for(Map.Entry> entry: table.entrySet()) {
if(first_element)
first_element=false;
else
sb.append(", ");
sb.append(entry.getKey()).append(" (");
Map owners=entry.getValue();
boolean first=true;
for(Map.Entry entry2: owners.entrySet()) {
if(first)
first=false;
else
sb.append(", ");
sb.append(entry2.getKey());
ClientLock cl=entry2.getValue();
if(!cl.acquired || cl.denied)
sb.append(", unlocked");
}
sb.append(")");
}
return sb.toString();
}
}
protected class ClientCondition implements Condition {
protected final ClientLock lock;
protected final AtomicBoolean signaled = new AtomicBoolean(false);
/**
* This is okay only having 1 since a client condition is 1 per
* lock_name, thread id combination.
*/
protected volatile AtomicReference parker=new AtomicReference<>();
public ClientCondition(ClientLock lock) {
this.lock = lock;
}
@Override
public void await() throws InterruptedException {
InterruptedException ex = null;
try {
await(true);
}
catch (InterruptedException e) {
ex = e;
throw ex;
}
finally {
lock.lock();
// If we are throwing an InterruptedException
// then clear the interrupt state as well.
if (ex != null) {
Thread.interrupted();
}
}
}
@Override
public void awaitUninterruptibly() {
try {
await(false);
}
catch(InterruptedException e) {
// This should never happen
}
finally {
lock.lock();
}
}
@Override
public long awaitNanos(long nanosTimeout) throws InterruptedException {
InterruptedException ex = null;
try {
return await(nanosTimeout);
}
catch (InterruptedException e) {
ex = e;
throw ex;
}
finally {
lock.lock(); // contract mandates we need to re-acquire the lock (see overridden method)
// If we are throwing an InterruptedException then clear the interrupt state as well
if (ex != null)
Thread.interrupted();
}
}
/**
* Note this wait will only work correctly if the converted value is less
* than 292 years. This is due to the limitation in System.nano and long
* values that can only store up to 292 years (2263 nanoseconds).
*
* For more information please see {@link System#nanoTime()}
*/
@Override
public boolean await(long time, TimeUnit unit) throws InterruptedException {
return awaitNanos(unit.toNanos(time)) > 0;
}
@Override
public boolean awaitUntil(Date deadline) throws InterruptedException {
long waitUntilTime = deadline.getTime();
long currentTime = System.currentTimeMillis();
long waitTime = waitUntilTime - currentTime;
if (waitTime > 0) {
return await(waitTime, TimeUnit.MILLISECONDS);
}
else {
return false;
}
}
protected void await(boolean throwInterrupt) throws InterruptedException {
if(!signaled.get()) {
lock.acquired = false;
sendAwaitConditionRequest(lock.name, lock.owner);
boolean interrupted=false;
while(!signaled.get()) {
parker.set(Thread.currentThread());
LockSupport.park(this);
if (Thread.interrupted()) {
// If we were interrupted and haven't received a response yet then we try to
// clean up the lock request and throw the exception
if (!signaled.get()) {
sendDeleteAwaitConditionRequest(lock.name, lock.owner);
throw new InterruptedException();
}
// In the case that we were signaled and interrupted
// we want to return the signal but still interrupt
// our thread
interrupted = true;
}
}
if(interrupted)
Thread.currentThread().interrupt();
}
// We set as if this signal was no released. This way if the
// condition is reused again, but the client condition isn't lost
// we won't think we were signaled immediately
signaled.set(false);
}
// Return the estimated time to wait (in ns), can be negative
protected long await(long nanoSeconds) throws InterruptedException {
long start=System.nanoTime();
if(!signaled.get()) {
// We release the lock at the same time as waiting on the
// condition
lock.acquired = false;
sendAwaitConditionRequest(lock.name, lock.owner);
boolean interrupted = false;
while(!signaled.get()) {
long wait_nano=nanoSeconds - (System.nanoTime() - start);
// If we waited max time break out
if(wait_nano > 0) {
parker.set(Thread.currentThread());
LockSupport.parkNanos(this, wait_nano);
if (Thread.interrupted()) {
// If we were interrupted and haven't received a response yet then we try to
// clean up the lock request and throw the exception
if (!signaled.get()) {
sendDeleteAwaitConditionRequest(lock.name, lock.owner);
throw new InterruptedException();
}
// In the case that we were signaled and interrupted
// we want to return the signal but still interrupt
// our thread
interrupted = true;
}
}
else {
break;
}
}
if(interrupted)
Thread.currentThread().interrupt();
}
// We set as if this signal was no released. This way if the
// condition is reused again, but the client condition isn't lost
// we won't think we were signaled immediately
// If we weren't signaled then delete our request
if (!signaled.getAndSet(false)) {
sendDeleteAwaitConditionRequest(lock.name, lock.owner);
}
return nanoSeconds - (System.nanoTime() - start);
}
@Override
public void signal() {
sendSignalConditionRequest(lock.name, false);
}
@Override
public void signalAll() {
sendSignalConditionRequest(lock.name, true);
}
protected void signaled() {
signaled.set(true);
Thread thread = parker.getAndSet(null);
if (thread != null)
LockSupport.unpark(thread);
}
}
protected static class Request implements Streamable {
protected Type type;
protected String lock_name;
protected int lock_id;
protected Owner owner;
protected long timeout;
protected boolean is_trylock;
public Request() {
}
public Request(Type type, String lock_name, Owner owner, long timeout) {
this.type=type;
this.lock_name=lock_name;
this.owner=owner;
this.timeout=timeout;
}
public Request(Type type, String lock_name, Owner owner, long timeout, boolean is_trylock) {
this(type, lock_name, owner, timeout);
this.is_trylock=is_trylock;
}
public Request lockId(int lock_id) {this.lock_id=lock_id; return this;}
public int lockId() {return lock_id;}
public void writeTo(DataOutput out) throws Exception {
out.writeByte(type.ordinal());
Bits.writeString(lock_name,out);
out.writeInt(lock_id);
Util.writeStreamable(owner, out);
out.writeLong(timeout);
out.writeBoolean(is_trylock);
}
public void readFrom(DataInput in) throws Exception {
type=Type.values()[in.readByte()];
lock_name=Bits.readString(in);
lock_id=in.readInt();
owner=(Owner)Util.readStreamable(Owner.class, in);
timeout=in.readLong();
is_trylock=in.readBoolean();
}
public String toString() {
return type.name() + " [" + lock_name + ", lock_id=" + lock_id + ", owner=" + owner + (is_trylock? ", trylock " : " ") +
(timeout > 0? "(timeout=" + timeout + ")" : "" + "]");
}
public String toStringShort() {
StringBuilder sb=new StringBuilder();
switch(type) {
case RELEASE_LOCK:
sb.append("U");
break;
case GRANT_LOCK:
sb.append(is_trylock? "TL" : "L");
break;
default:
sb.append("N/A");
break;
}
sb.append("(").append(lock_name).append(",").append(owner);
if(timeout > 0)
sb.append(",").append(timeout);
sb.append(")");
return sb.toString();
}
}
/** A response to a request, to be sent back to the requester as a message */
protected static class Response {
protected final Type type;
protected final Owner owner;
protected final String lock_name;
protected final int lock_id;
public Response(Type type, Owner owner, String lock_name, int lock_id) {
this.type=type;
this.owner=owner;
this.lock_name=lock_name;
this.lock_id=lock_id;
}
}
public static class LockingHeader extends Header {
public LockingHeader() {
}
public int size() {
return 0;
}
public void writeTo(DataOutput out) throws Exception {
}
public void readFrom(DataInput in) throws Exception {
}
}
}
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