org.hd.d.pg2k.test.dev
Class SimpleCacheTest.DataConcurrencyAccessMonitor

java.lang.Object
  org.hd.d.pg2k.svrCore.datasource.SimpleExhibitPipelineFilter
      org.hd.d.pg2k.test.dev.SimpleCacheTest.DataConcurrencyAccessMonitor

All Implemented Interfaces:

SimpleExhibitPipelineIF, BasicVarMgrInterface, SimpleVariablePipelineIF

Enclosing class:

SimpleCacheTest

static final class SimpleCacheTest.DataConcurrencyAccessMonitor
extends SimpleExhibitPipelineFilter

Thread-safe monitor of data-read activity. An instance of this class can be inserted into a pipeline to record or modify data-read activity.

dontBlock

private volatile boolean dontBlock

Once true, threads do not block in getRawFile(); volatile so as not to need the mutex.

blockedThreadsCount

private int blockedThreadsCount

Count of blocked thread in getRawData(). Must only be accessed under protection of the notifier mutex.

notifier

private final java.lang.Object notifier

Used to notify/wake blocked threads.

SimpleCacheTest.DataConcurrencyAccessMonitor

SimpleCacheTest.DataConcurrencyAccessMonitor(SimpleExhibitPipelineIF upstream)

getBlockedThreadsCount

private int getBlockedThreadsCount()

Get count of blocked thread in getRawData(); non-negative.

release

void release()

Call this to release any waiting/blocked threads in getRawFile().

getRawFile

public void getRawFile(java.nio.ByteBuffer buf,
                       Name.ExhibitFull exhibitName,
                       int position,
                       boolean dontCache)
                throws java.io.IOException

Intercept and block calls as if blocked waiting for disc access.

Specified by:

getRawFile in interface SimpleExhibitPipelineIF

Overrides:

getRawFile in class SimpleExhibitPipelineFilter

Parameters:

buf - the buffer into which to read the data; must be non-null, in put()able state, and with remaining capacity of at least the requested number of bytes

exhibitName - the full name of the exhibit to read from; never null and must be syntactically valid

position - position/index of first byte in exhibitFile to read; non-negative

dontCache - if true, this is a hint not to attempt to cache this or displace anything from extant caches for this data as it maqy for example be precaching or random activity; by default callers should leave this false to allow cacheing

Throws:

java.io.IOException - for requests that cannot be fulfilled because of I/O restrictions or problems, such as link failure or an upper bound on the length of a request