org.apache.river.outrigger

Class TxnMonitor

java.lang.Object

org.apache.river.outrigger.TxnMonitor

All Implemented Interfaces:

Runnable

class TxnMonitor
extends Object
implements Runnable

This class provides a driver for monitoring the state of transactions that have blocked progress of other operations recently. It creates tasks that monitor each transaction by intermittently querying the transaction's state. If it finds that the transaction has aborted, it makes sure that the local space aborts the transaction, too, so that operations will cease to be blocked by the transaction.

Author:

Sun Microsystems, Inc.

See Also:

TxnMonitorTask, OutriggerServerImpl.monitor(org.apache.river.outrigger.QueryWatcher, java.util.Collection<org.apache.river.outrigger.Txn>)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	TxnMonitor.ToMonitor Each ToMonitor object represents a need to monitor the given transactions, possibly under a lease.

Field Summary

Fields

Modifier and Type	Field and Description
private static Logger	logger Logger for logging transaction related information
private Thread	ourThread The thread running us.
private LinkedList<TxnMonitor.ToMonitor>	pending This list is used to contain requests to monitor interfering transactions.
private OutriggerServerImpl	space The space we belong to.
private boolean	started
private java.util.concurrent.ExecutorService	taskManager The manager for TxnMonitorTask objects.
private WakeupManager	wakeupMgr wakeup manager for TxnMonitorTasks

Constructor Summary

Constructors

Constructor and Description
TxnMonitor(OutriggerServerImpl space, Configuration config) Create a new TxnMonitor.

Method Summary

Modifier and Type	Method and Description
(package private) void	add(Collection<Txn> transactions) Add a set of transactions to be monitored under no lease.
(package private) void	add(QueryWatcher query, Collection<Txn> transactions) Add a set of transactions to be monitored under the given query.
void	destroy()
void	run() Take pending monitor requests off the queue, creating the required TxnMonitorTask objects and scheduling them.
(package private) OutriggerServerImpl	space() Return the space we're part of.
void	start()
private TxnMonitorTask	taskFor(Txn txn) Return the monitor task for this transaction, creating it if necessary.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

pending

private final LinkedList<TxnMonitor.ToMonitor> pending

This list is used to contain requests to monitor interfering transactions. We use a list like this so that the getMatch request that detected the conflict doesn't have to wait for all the setup before returning -- it just puts the data on this list and the TxnMonitor pulls it off using its own thread.

See Also:

OutriggerServerImpl.getMatch(org.apache.river.outrigger.EntryRep, net.jini.core.transaction.Transaction, long, boolean, boolean, org.apache.river.outrigger.OutriggerServer.QueryCookie)

wakeupMgr

private final WakeupManager wakeupMgr

wakeup manager for TxnMonitorTasks

taskManager

private final java.util.concurrent.ExecutorService taskManager

The manager for TxnMonitorTask objects.

space

private final OutriggerServerImpl space

The space we belong to. Needed for aborts.

ourThread

private final Thread ourThread

The thread running us.

started

private volatile boolean started

logger

private static final Logger logger

Logger for logging transaction related information

Constructor Detail

TxnMonitor

TxnMonitor(OutriggerServerImpl space,
           Configuration config)
    throws ConfigurationException

Create a new TxnMonitor.

Throws:

ConfigurationException

Method Detail

start

public void start()

destroy

public void destroy()

space

OutriggerServerImpl space()

Return the space we're part of.

add

void add(QueryWatcher query,
         Collection<Txn> transactions)

Add a set of transactions to be monitored under the given query.

add

void add(Collection<Txn> transactions)

Add a set of transactions to be monitored under no lease.

run

public void run()

Take pending monitor requests off the queue, creating the required TxnMonitorTask objects and scheduling them.

Specified by:

run in interface Runnable

taskFor

private TxnMonitorTask taskFor(Txn txn)

Return the monitor task for this transaction, creating it if necessary.