Class BufferedAny2AnyChannel<T>
- All Implemented Interfaces:
Any2AnyChannel<T>
,ChannelInternals<T>
Description
BufferedAny2AnyChannel implements an any-to-any object channel with user-definable buffering. It is safe for use by any number of reading or writing processes. Reading processes compete with each other to use the channel. Writing processes compete with each other to use the channel. Only the reader and one writer will actually be using the channel at any one time. This is taken care of by BufferedAny2AnyChannel -- user processes just read from or write to it.
Please note that this is a safely shared channel and not
a multicaster. Currently, multicasting has to be managed by
writing active processes (see DynamicDelta
for an example of broadcasting).
All reading processes and writing processes commit to the channel
(i.e. may not back off). This means that the reading processes
may not ALT
on this channel.
The constructor requires the user to provide
the channel with a plug-in driver conforming to the
ChannelDataStore
interface. This allows a variety of different channel semantics to be
introduced -- including buffered channels of user-defined capacity
(including infinite), overwriting channels (with various overwriting
policies) etc..
Standard examples are given in the org.jcsp.util package, but
careful users may write their own.
Implementation Note and Caution
Fair servicing of readers and writers to this channel depends on the fair servicing of requests to enter a synchronized block (or method) by the underlying Java Virtual Machine (JVM). Java does not specify how threads waiting to synchronize should be handled. Currently, Sun's standard JDKs queue these requests - which is fair. However, there is at least one JVM that puts such competing requests on a stack - which is legal but unfair and can lead to infinite starvation. This is a problem for any Java system relying on good behaviour from synchronized, not just for these any-any channels.-
Constructor Summary
ConstructorsConstructorDescriptionConstructs a new BufferedAny2AnyChannel with the specified ChannelDataStore. -
Method Summary
Methods inherited from class org.jcsp.lang.Any2AnyImpl
endRead, in, out, read, readerDisable, readerEnable, readerPending, readerPoison, startRead, write, writerPoison
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Constructor Details
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BufferedAny2AnyChannel
Constructs a new BufferedAny2AnyChannel with the specified ChannelDataStore.- Parameters:
data
- The ChannelDataStore used to store the data for the channel
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