class PoisonableOne2OneChannelImpl<T> extends java.lang.Object implements One2OneChannel<T>, java.io.Serializable, ChannelInternals<T>
Any2OneChannelImpl
,
One2AnyChannelImpl
or
Any2AnyChannelImpl
.
The reading process may ALT
on this channel.
The writing process is committed (i.e. it may not back off).
The default semantics of the channel is that of CSP -- i.e. it is zero-buffered and fully synchronised. The reading process must wait for a matching writer and vice-versa.
However, the static methods of Channel
allow the creation of
a 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.
Modifier and Type | Field and Description |
---|---|
private Alternative |
alt
The Alternative class that controls the selection
|
private boolean |
done
This flag indicates that the last transfer went OK.
|
private boolean |
empty
The synchronisation flag
|
private T |
hold
The (invisible-to-users) buffer used to store the data for the channel
|
private int |
immunity
Immunity is passed to the channel-ends, and is not used directly by the channel algorithms
|
private int |
poisonStrength
0 means unpoisoned
|
private java.lang.Object |
rwMonitor
The monitor synchronising reader and writer on this channel
|
private boolean |
spuriousWakeUp
Flag to deal with a spurious wakeup during a write
|
Constructor and Description |
---|
PoisonableOne2OneChannelImpl(int _immunity) |
Modifier and Type | Method and Description |
---|---|
void |
endRead() |
AltingChannelInput<T> |
in()
Returns the
AltingChannelInput to use for this channel. |
private boolean |
isPoisoned() |
ChannelOutput<T> |
out()
Returns the
ChannelOutput object to use for this channel. |
T |
read()
Reads an Object from the channel.
|
boolean |
readerDisable()
turns off Alternative selection for the channel.
|
boolean |
readerEnable(Alternative alt)
turns on Alternative selection for the channel.
|
boolean |
readerPending()
Returns whether there is data pending on this channel.
|
void |
readerPoison(int strength) |
T |
startRead() |
void |
write(T value)
Writes an Object to the channel.
|
void |
writerPoison(int strength) |
private java.lang.Object rwMonitor
private T hold
private boolean empty
private boolean done
private int poisonStrength
private int immunity
private Alternative alt
private boolean spuriousWakeUp
private boolean isPoisoned()
public AltingChannelInput<T> in()
AltingChannelInput
to use for this channel.
As One2OneChannelImpl
implements
AltingChannelInput
itself, this method simply returns
a reference to the object that it is called on.in
in interface One2OneChannel<T>
AltingChannelInput
object to use for this
channel.public ChannelOutput<T> out()
ChannelOutput
object to use for this channel.
As One2OneChannelImpl
implements
ChannelOutput
itself, this method simply returns
a reference to the object that it is called on.out
in interface One2OneChannel<T>
ChannelOutput
object to use for this
channel.public void write(T value)
write
in interface ChannelInternals<T>
value
- the object to write to the channel.public T read()
read
in interface ChannelInternals<T>
public T startRead()
startRead
in interface ChannelInternals<T>
public void endRead()
endRead
in interface ChannelInternals<T>
public boolean readerEnable(Alternative alt)
Note: this method should only be called by the Alternative class
readerEnable
in interface ChannelInternals<T>
alt
- the Alternative class which will control the selectionpublic boolean readerDisable()
Note: this method should only be called by the Alternative class
readerDisable
in interface ChannelInternals<T>
public boolean readerPending()
Note: if there is, it won't go away until you read it. But if there isn't, there may be some by the time you check the result of this method.
This method is provided for convenience. Its functionality can be provided by Pri Alting the channel against a SKIP guard, although at greater run-time and syntactic cost. For example, the following code fragment:
if (c.pending ()) { Object x = c.read (); ... do something with x } else ( ... do something else }is equivalent to:
if (c_pending.priSelect () == 0) { Object x = c.read (); ... do something with x } else ( ... do something else }where earlier would have had to have been declared:
final Alternative c_pending = new Alternative (new Guard[] {c, new Skip ()});
readerPending
in interface ChannelInternals<T>
public void writerPoison(int strength)
writerPoison
in interface ChannelInternals<T>
public void readerPoison(int strength)
readerPoison
in interface ChannelInternals<T>