Class BufferedOne2OneChannelIntImpl
- java.lang.Object
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- org.jcsp.lang.BufferedOne2OneChannelIntImpl
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- All Implemented Interfaces:
ChannelInternalsInt
,One2OneChannelInt
class BufferedOne2OneChannelIntImpl extends java.lang.Object implements One2OneChannelInt, ChannelInternalsInt
This implements a one-to-one integer channel with user-definable buffering.Description
BufferedOne2OneChannelIntImpl implements a one-to-one integer channel with user-definable buffering. Multiple readers or multiple writers are not allowed -- these are catered for byBufferedAny2OneChannel
,BufferedOne2AnyChannel
orBufferedAny2AnyChannel
.The reading process may
ALT
on this channel. The writing process is committed (i.e. it may not back off).The constructor requires the user to provide the channel with a plug-in driver conforming to the
ChannelDataStoreInt
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.
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Field Summary
Fields Modifier and Type Field Description private Alternative
alt
The Alternative class that controls the selectionprivate ChannelDataStoreInt
data
The ChannelDataStoreInt used to store the data for the channelprivate java.lang.Object
rwMonitor
The monitor synchronising reader and writer on this channel
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Constructor Summary
Constructors Constructor Description BufferedOne2OneChannelIntImpl(ChannelDataStoreInt data)
Constructs a new BufferedOne2OneChannelIntImpl with the specified ChannelDataStoreInt.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
endRead()
AltingChannelInputInt
in()
Returns theAltingChannelInputInt
object to use for this channel.ChannelOutputInt
out()
Returns theChannelOutputInt
object to use for this channel.int
read()
Reads an int 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)
int
startRead()
void
write(int value)
Writes an int to the channel.void
writerPoison(int strength)
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Field Detail
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rwMonitor
private java.lang.Object rwMonitor
The monitor synchronising reader and writer on this channel
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alt
private Alternative alt
The Alternative class that controls the selection
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data
private final ChannelDataStoreInt data
The ChannelDataStoreInt used to store the data for the channel
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Constructor Detail
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BufferedOne2OneChannelIntImpl
public BufferedOne2OneChannelIntImpl(ChannelDataStoreInt data)
Constructs a new BufferedOne2OneChannelIntImpl with the specified ChannelDataStoreInt.- Parameters:
data
- the ChannelDataStoreInt used to store the data for the channel
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Method Detail
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in
public AltingChannelInputInt in()
Returns theAltingChannelInputInt
object to use for this channel. AsOne2OneChannelIntImpl
implementsAltingChannelInputInt
itself, this method simply returns a reference to the object that it is called on.- Specified by:
in
in interfaceOne2OneChannelInt
- Returns:
- the
AltingChannelInputInt
object to use for this channel.
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out
public ChannelOutputInt out()
Returns theChannelOutputInt
object to use for this channel. AsOne2OneChannelIntImpl
implementsChannelOutputInt
itself, this method simply returns a reference to the object that it is called on.- Specified by:
out
in interfaceOne2OneChannelInt
- Returns:
- the
ChannelOutputInt
object to use for this channel.
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read
public int read()
Reads an int from the channel.- Specified by:
read
in interfaceChannelInternalsInt
- Returns:
- the integer read from the channel.
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startRead
public int startRead()
- Specified by:
startRead
in interfaceChannelInternalsInt
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endRead
public void endRead()
- Specified by:
endRead
in interfaceChannelInternalsInt
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write
public void write(int value)
Writes an int to the channel.- Specified by:
write
in interfaceChannelInternalsInt
- Parameters:
value
- the integer to write to the channel.
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readerEnable
public boolean readerEnable(Alternative alt)
turns on Alternative selection for the channel. Returns true if the channel has data that can be read immediately.Note: this method should only be called by the Alternative class
- Specified by:
readerEnable
in interfaceChannelInternalsInt
- Parameters:
alt
- the Alternative class which will control the selection- Returns:
- true if the channel has data that can be read, else false
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readerDisable
public boolean readerDisable()
turns off Alternative selection for the channel. Returns true if the channel contained data that can be read.Note: this method should only be called by the Alternative class
- Specified by:
readerDisable
in interfaceChannelInternalsInt
- Returns:
- true if the channel has data that can be read, else false
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readerPending
public boolean readerPending()
Returns whether there is data pending on this channel.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 ()) { int x = c.read (); ... do something with x } else ( ... do something else }
is equivalent to:if (c_pending.priSelect () == 0) { int 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 ()});
- Specified by:
readerPending
in interfaceChannelInternalsInt
- Returns:
- state of the channel.
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writerPoison
public void writerPoison(int strength)
- Specified by:
writerPoison
in interfaceChannelInternalsInt
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readerPoison
public void readerPoison(int strength)
- Specified by:
readerPoison
in interfaceChannelInternalsInt
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