de.yaacc.share.ShareConcurrencyLimiter Class Reference

Caps the number of responses that are streaming from one share at the same time. More...

Collaboration diagram for de.yaacc.share.ShareConcurrencyLimiter:

Classes
class	Lease
	One running response; release() is idempotent.
enum	State

Public Member Functions
	ShareConcurrencyLimiter (int max)
	ShareConcurrencyLimiter (int max, LongSupplier clock)
Lease	tryAcquire (String key)
int	expireIdle (long idleMillis)
	Takes the slot away from every lease that made no progress for more than idleMillis.
int	activeCount (String key)
int	trackedKeys ()

Static Public Member Functions
static ShareConcurrencyLimiter	shared ()
	The limiter of the whole process (the HTTP server's responses and the sweeper share it).

Detailed Description

Caps the number of responses that are streaming from one share at the same time.

A response takes a Lease before it starts and gives it back when it ends; the lease can be released any number of times (the HTTP library may report the end of a response through more than one callback). Plain Java, thread safe.

Watchdog: a response reports its progress to the lease (Lease#noteProgress); a periodic expireIdle takes the slot away from a lease that made no progress for the idle time, so a stalled or trickling reader cannot hold the slots of a share. The response itself is not cut off: if it is called again (the reader resumed after a pause) it asks for a slot again (Lease#tryReacquire(), same cap) and aborts only if the share is full. The slot is given back exactly once, however often a lease expired and resumed.

Constructor & Destructor Documentation

ShareConcurrencyLimiter() [1/2]

de.yaacc.share.ShareConcurrencyLimiter.ShareConcurrencyLimiter

(

int

max

)

Exceptions

IllegalArgumentException

if max is not positive

ShareConcurrencyLimiter() [2/2]

de.yaacc.share.ShareConcurrencyLimiter.ShareConcurrencyLimiter	(	int	max,
		LongSupplier	clock )

Parameters

clock

monotonic milliseconds

Exceptions

IllegalArgumentException

if max is not positive

Member Function Documentation

activeCount()

int de.yaacc.share.ShareConcurrencyLimiter.activeCount

(

String

key

)

Returns

the number of responses currently holding a lease for the key

expireIdle()

int de.yaacc.share.ShareConcurrencyLimiter.expireIdle

(

long

idleMillis

)

Takes the slot away from every lease that made no progress for more than idleMillis.

Call it periodically (the share sweeper does, every minute).

Returns

the number of leases that were expired

Exceptions

IllegalArgumentException

if idleMillis is not positive

trackedKeys()

int de.yaacc.share.ShareConcurrencyLimiter.trackedKeys

(

)

Returns

the number of keys with at least one lease (bookkeeping size, for tests)

tryAcquire()

Lease de.yaacc.share.ShareConcurrencyLimiter.tryAcquire

(

String

key

)

Parameters

key	a well-formed share key (ShareRegistry#isWellFormedKey)

Returns

a lease, or null if the share already serves the maximum or the key is malformed

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The documentation for this class was generated from the following file:

• /github/workspace/yaacc/src/main/java/de/yaacc/share/ShareConcurrencyLimiter.java