public class CNS
This class is the Channel Name Server's main server process class.
This class should only be instantiated at Nodes wishing to run a server process. Although this class does not need to
be used by clients wishing to interact with a server, it does provide some convenient static methods for client code
to use. There are static versions of the methods provided in CNSService
and there are also static
factory methods for constructing CNS registered channel objects.
Channel Name Servers may be run either on a dedicated Node or else on the same Node as one of the user Nodes. The former approach is recommended for most situations but for smaller scale use, the latter approach may suffice.
The following example initialises a Node and installs a Channel Name Server. It then proceeds to install a CNS client service and creates and resolves a channel. The example does not proceed to do anything else but could be used as the framework for an application wishing to host its own Channel Name Server.
import org.jcsp.lang.*;
import org.jcsp.net2.*;
import org.jcsp.net2.cns.*;
import org.jcsp.net2.tcpip.*;
import java.io.IOException;
public class CNSInSameJVM implements CSProcess {
//main method for running example
public static void main(String[] args) {
CNSInSameJVM proc = new CNSInSameJVM();
proc.run();
}
public void run() {
NodeKey key = null;
NodeID localNodeID = null;
try {
//Initialize a Node that does not have a CNS client
key = Node.getInstance().init(new TCPIPNodeAddress(7890));
new ProcessManager(CNS.getInstance()).start();
//Dedicated server code could stop here
//Initialise the CNS client
//use the local NodeID to connect to the CNS
localNodeID = Node.getInstance().getNodeID();
CNS.init(localNodeID);
// creating Channel named "in"
NetChannelInput in = CNS.net2one("in");
//resolve the channel
NetChannelOutput out = CNS.one2net("in");
//could now use these channels for something!!
//but this is only a test so will terminate
} catch (NodeInitFailedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Node.log.log(this, "Done."); } }
In order to construct a ChannelInput
object which can be resolved by other users of a channel name
server, a client simply needs to to do this:
NetChannelInput in = CNS.net2one("Fred");
Another process using the same channel name server can create a ChannelOutput
that will send objects
to this channel by do this:
NetChannelOutput out = CNS.one2net("Fred");
When these factory methods are called, various resources are used within the JCSP infrastructure. A channel name will be registered and held in the channel name server. These resources are taken for the duration of the JCSP Node's runtime.
This is an example "Hello World" program which contains two inner classes with main methods, each of which can be run in separate JVMs.
import org.jcsp.lang.*; import org.jcsp.net2.*; import org.jcsp.net2.cns.*; public class TestCNS { public static class Rx { public static void main(String[] args) { try { Node.getInstance().init(new TCPIPNodeAddress(7890)); NetChannelInput in = CNS.net2one("rx.in"); System.out.println(in.read()); } catch (Exception e) { e.printStackTrace(); } } } public static class Tx { public static void main(String[] args) { try { Node.getInstance().init(new TCPIPNodeAddress(7890)); NetChannelOutput out = CNS.one2net("rx.in"); out.write("Hello World"); } catch (Exception e) { e.printStackTrace(); } } } }
This code can be compiled and then the following run at two command prompts:
java TestCNS$Rx
java TestCNS$Tx
The programs will connect to a default channel name server. The Rx program will create a NetChannelInput
and wait for a message on the channel. Once it has received the message, it prints it, then terminates. The Tx
program creates a NetChannelOutput
that will send to the Rx program's input channel. It sends a "Hello
World" message. Once this has been accepted by the Rx process, it terminates.
Type | Name and description |
---|---|
static NetSharedChannelOutput |
any2net(String name) Creates a new NetSharedChannelOutput connected to the input channel registered with the given name |
static NetSharedChannelOutput |
any2net(String name, int immunityLevel) Creates a new NetSharedChannelOutput connected to the input channel registered with the given name |
static NetSharedChannelOutput |
any2net(String name, FilterTx filter) Creates a new NetSharedChannelOutput connected to the input channel registered with the given name |
static NetSharedChannelOutput |
any2net(String name, int immunityLevel, FilterTx filter) Creates a new NetSharedChannelOutput connected to the input channel registered with the given name |
static NetSharedChannelOutput |
createAny2Net(String name) Creates a new NetSharedChannelOutput connected to the input channel registered with the given name |
static NetSharedChannelInput |
createNet2Any(String name) Creates a new NetSharedChannelInput registered with the given name |
static NetAltingChannelInput |
createNet2One(String name) Creates a new NetAltingChannelInput registered with the given name |
static NetChannelOutput |
createOne2Net(String name) Creates a new NetChannelOutput connected to the input channel registered with the given name |
static CNS |
getInstance() Gets the singleton instance of the CNS |
static void |
initialise(NodeID cnsNode) Initialises the factory methods to allow creation of channels with the CNS |
static void |
initialise(NodeAddress cnsNode) Initialises the factory methods to allow creation of channels with the CNS |
static NetSharedChannelInput |
net2any(String name) Creates a new NetSharedChannelInput registered with the given name |
static NetSharedChannelInput |
net2any(String name, int immunityLevel) Creates a new NetSharedChannelInput registered with the given name |
static NetSharedChannelInput |
net2any(String name, FilterRx filter) Creates a new NetSharedChannelInput registered with the given name |
static NetSharedChannelInput |
net2any(String name, int immunityLevel, FilterRx filter) Creates a new NetSharedChannelInput registered with the given name |
static NetAltingChannelInput |
net2one(String name) Creates a new NetAltingChannelInput registered with the given name |
static NetAltingChannelInput |
net2one(String name, int immunityLevel) Creates a new NetAltingChannelInput registered with the given name |
static NetAltingChannelInput |
net2one(String name, FilterRx filter) Creates a new NetAltingChannelInput registered with the given name |
static NetAltingChannelInput |
net2one(String name, int immunityLevel, FilterRx filter) Creates a new NetAltingChannelInput registered with the given name |
static NetSharedChannelInput |
numberedNet2Any(String name, int index) Creates a new NetSharedChannelInput registered with the given name |
static NetSharedChannelInput |
numberedNet2Any(String name, int index, int immunityLevel) Creates a new NetSharedChannelInput registered with the given name |
static NetSharedChannelInput |
numberedNet2Any(String name, int index, FilterRx filter) Creates a new NetSharedChannelInput registered with the given name |
static NetSharedChannelInput |
numberedNet2Any(String name, int index, int immunityLevel, FilterRx filter) Creates a new NetSharedChannelInput registered with the given name |
static NetAltingChannelInput |
numberedNet2One(String name, int index) Creates a new NetAltingChannelInput registered with the given name |
static NetAltingChannelInput |
numberedNet2One(String name, int index, int immunityLevel) Creates a new NetAltingChannelInput registered with the given name |
static NetAltingChannelInput |
numberedNet2One(String name, int index, FilterRx filter) Creates a new NetAltingChannelInput registered with the given name |
static NetAltingChannelInput |
numberedNet2One(String name, int index, int immunityLevel, FilterRx filter) Creates a new NetAltingChannelInput registered with the given name |
static NetChannelOutput |
one2net(String name) Creates a new NetChannelOutput connected to the input channel registered with the given name |
static NetChannelOutput |
one2net(String name, int immunityLevel) Creates a new NetChannelOutput connected to the input channel registered with the given name |
static NetChannelOutput |
one2net(String name, FilterTx filter) Creates a new NetChannelOutput connected to the input channel registered with the given name |
static NetChannelOutput |
one2net(String name, int immunityLevel, FilterTx filter) Creates a new NetChannelOutput connected to the input channel registered with the given name |
void |
run() The run method for the CNS process |
Creates a new NetSharedChannelOutput connected to the input channel registered with the given name
name
- The name to resolveCreates a new NetSharedChannelOutput connected to the input channel registered with the given name
name
- The name to resolveimmunityLevel
- The immunity to poison that this channel hasCreates a new NetSharedChannelOutput connected to the input channel registered with the given name
name
- The name to resolvefilter
- The filter used to encode outgoing messagesCreates a new NetSharedChannelOutput connected to the input channel registered with the given name
name
- The name to resolveimmunityLevel
- The immunity level to poison that this channel hasfilter
- The filter used to encode outgoing messagesCreates a new NetSharedChannelOutput connected to the input channel registered with the given name
name
- The name to resolveCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSCreates a new NetChannelOutput connected to the input channel registered with the given name
name
- The name to resolveGets the singleton instance of the CNS
Initialises the factory methods to allow creation of channels with the CNS
cnsNode
- The Node that the CNS is located onInitialises the factory methods to allow creation of channels with the CNS
cnsNode
- The Node that the CNS is located onCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSimmunityLevel
- The immunity level to poison that the channel hasCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSfilter
- The filter used to decode incoming messagesCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSimmunityLevel
- The immunity to poison that this channel hasfilter
- The filter used to decode incoming messagesCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSimmunityLevel
- The immunity to poison the channel hasCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSfilter
- The filter used to decode incoming messagesCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSimmunityLevel
- The immunity level to poison that the channel hasfilter
- The filter used to decode incoming messagesCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withimmunityLevel
- The immunity to poison that this channel hasCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withfilter
- The filter used to decode incoming messagesCreates a new NetSharedChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withimmunityLevel
- The immunity to poison that this channel hasfilter
- The filter used to decode incoming messagesCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withimmunityLevel
- The immunity level to poison that the channel hasCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withfilter
- The filter used to decode incoming messagesCreates a new NetAltingChannelInput registered with the given name
name
- The name to register with the CNSindex
- The index to create the channel withimmunityLevel
- The immunity level to poison that the channel hasfilter
- The filter used to decode incoming messagesCreates a new NetChannelOutput connected to the input channel registered with the given name
name
- The name to resolveCreates a new NetChannelOutput connected to the input channel registered with the given name
name
- The name to resolveimmunityLevel
- The immunity to poison that this channel hasCreates a new NetChannelOutput connected to the input channel registered with the given name
name
- The name to resolvefilter
- The filter used to encode outgoing messagesCreates a new NetChannelOutput connected to the input channel registered with the given name
name
- The name to resolveimmunityLevel
- The immunity to poison that this channel hasfilter
- The filter used to encode outgoing messagesThe run method for the CNS process