org.apache.river.outrigger

Class TemplateHandle

java.lang.Object

org.apache.river.outrigger.BaseHandle

org.apache.river.outrigger.TemplateHandle

class TemplateHandle
extends BaseHandle

TemplateHandle associates one or more TransitionWatchers with a template. Unless otherwise noted all methods are thread safe.

Field Summary

Fields

Modifier and Type	Field and Description
private OutriggerServerImpl	owner The WatchersForTemplateClass this object belongs to.
private boolean	removed
private java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock	rl
private Set<TransitionWatcher>	watchers The watchers.
private java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock	wl WriteLock guarantees that no updates can be performed during a removal operation.

Constructor Summary

Constructors

Constructor and Description
TemplateHandle(EntryRep tmpl, OutriggerServerImpl owner, Queue<TemplateHandle> content) Create a handle for the template tmpl.

Method Summary

Modifier and Type	Method and Description
(package private) boolean	addTransitionWatcher(TransitionWatcher watcher) Add a watcher to this handle.
(package private) void	collectInterested(Set<TransitionWatcher> set, EntryTransition transition, long ordinal) Iterate over the watchers associated with this handle calling isInterested on each and if it returns true adding the watcher to the passed set.
(package private) EntryHandleTmplDesc	descFor(int index) Return the description for the given field count.
(package private) OutriggerServerImpl	getServer() Return the OutriggerServerImpl this handle is part of.
(package private) boolean	matches(EntryRep entry) Return true if this template matches the given entry.
(package private) void	reap(long now) Visit each TransitionWatcher and check to see if it has expired, removing it if it has.
boolean	remove() Overridden and called from subclass.
boolean	removed()
(package private) boolean	removeIfEmpty() Need to lock on the wl so no one will add a watcher between the check for empty and when it gets removed.
(package private) void	removeTransitionWatcher(TransitionWatcher watcher) Remote a watcher from this handle.

Methods inherited from class org.apache.river.outrigger.BaseHandle

classFor, rep

Methods inherited from class java.lang.Object

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

Field Detail

watchers

private final Set<TransitionWatcher> watchers

The watchers. We use a HashSet because we will probably do a fair number of removals for each traversal and the number of watchers managed by one TemplateHandle will probably never get very large. If this does become an issue making TransitionWatcher extend FastList.Node and using a FastList here would probably be a good choice (though that would require changing FastList to support overlapping traversals of different lists from the same thread.)

wl

private final java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock wl

WriteLock guarantees that no updates can be performed during a removal operation.

rl

private final java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock rl

removed

private boolean removed

owner

private final OutriggerServerImpl owner

The WatchersForTemplateClass this object belongs to.

Constructor Detail

TemplateHandle

TemplateHandle(EntryRep tmpl,
               OutriggerServerImpl owner,
               Queue<TemplateHandle> content)

Create a handle for the template tmpl.

Method Detail

descFor

EntryHandleTmplDesc descFor(int index)

Return the description for the given field count.

matches

boolean matches(EntryRep entry)

Return true if this template matches the given entry.

addTransitionWatcher

boolean addTransitionWatcher(TransitionWatcher watcher)

Add a watcher to this handle. Assumes that the handle has not been removed.

Parameters:

watcher - the watcher to be added.

Returns:

true if watcher is added, false otherwise.

Throws:

NullPointerException - if watcher is null.

removeTransitionWatcher

void removeTransitionWatcher(TransitionWatcher watcher)

Remote a watcher from this handle. Does nothing if the specified watcher is not associated with this TemplateHandle.

Parameters:

watcher - the watcher to be removed.

Throws:

NullPointerException - if watcher is null.

collectInterested

void collectInterested(Set<TransitionWatcher> set,
                       EntryTransition transition,
                       long ordinal)

Iterate over the watchers associated with this handle calling isInterested on each and if it returns true adding the watcher to the passed set.

Parameters:

set - The set to accumulate interested watchers into.

transition - The transition being processed.

ordinal - The ordinal associated with transition.

Throws:

NullPointerException - if either argument is null.

getServer

OutriggerServerImpl getServer()

Return the OutriggerServerImpl this handle is part of.

Returns:

The OutriggerServerImpl this handle is part of.

reap

void reap(long now)

Visit each TransitionWatcher and check to see if it has expired, removing it if it has.

Parameters:

now - an estimate of the current time expressed as milliseconds since the beginning of the epoch.

removeIfEmpty

boolean removeIfEmpty()

Need to lock on the wl so no one will add a watcher between the check for empty and when it gets removed.

removed

public boolean removed()

Specified by:

removed in class BaseHandle

remove

public boolean remove()

Description copied from class: BaseHandle

Overridden and called from subclass.

Overrides:

remove in class BaseHandle

Returns:

true if removed.