com.ericsson.otp.erlang
Class OtpSelf

java.lang.Object
  extended by com.ericsson.otp.erlang.AbstractNode
      extended by com.ericsson.otp.erlang.OtpLocalNode
          extended by com.ericsson.otp.erlang.OtpSelf
Direct Known Subclasses:
OtpServer

public class OtpSelf
extends OtpLocalNode

Represents an OTP node. It is used to connect to remote nodes or accept incoming connections from remote nodes.

When the Java node will be connecting to a remote Erlang, Java or C node, it must first identify itself as a node by creating an instance of this class, after which it may connect to the remote node.

When you create an instance of this class, it will bind a socket to a port so that incoming connections can be accepted. However the port number will not be made available to other nodes wishing to connect until you explicitely register with the port mapper daemon by calling publishPort().

 OtpSelf self = new OtpSelf("client", "authcookie"); // identify self
 OtpPeer other = new OtpPeer("server"); // identify peer
 
 OtpConnection conn = self.connect(other); // connect to peer
 


Field Summary
 
Fields inherited from class com.ericsson.otp.erlang.OtpLocalNode
epmd, port
 
Constructor Summary
OtpSelf(java.lang.String node)
           Create a self node using the default cookie.
OtpSelf(java.lang.String node, java.lang.String cookie)
          Create a self node.
OtpSelf(java.lang.String node, java.lang.String cookie, int port)
           
 
Method Summary
 OtpConnection accept()
          Accept an incoming connection from a remote node.
 OtpConnection connect(OtpPeer other)
          Open a connection to a remote node.
 OtpErlangPid pid()
          Get the Erlang PID that will be used as the sender id in all "anonymous" messages sent by this node.
 boolean publishPort()
          Make public the information needed by remote nodes that may wish to connect to this one.
 void unPublishPort()
          Unregister the server node's name and port number from the Erlang port mapper, thus preventing any new connections from remote nodes.
 
Methods inherited from class com.ericsson.otp.erlang.OtpLocalNode
createPid, createPort, createRef, getEpmd, port, setEpmd
 
Methods inherited from class com.ericsson.otp.erlang.AbstractNode
alive, cookie, host, node, setCookie, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

OtpSelf

public OtpSelf(java.lang.String node)
        throws java.io.IOException

Create a self node using the default cookie. The default cookie is found by reading the first line of the .erlang.cookie file in the user's home directory. The home directory is obtained from the System property "user.home".

If the file does not exist, an empty string is used. This method makes no attempt to create the file.

Parameters:
node - the name of this node.
Throws:
java.io.IOException

OtpSelf

public OtpSelf(java.lang.String node,
               java.lang.String cookie)
        throws java.io.IOException
Create a self node.

Parameters:
node - the name of this node.
cookie - the authorization cookie that will be used by this node when it communicates with other nodes.
Throws:
java.io.IOException

OtpSelf

public OtpSelf(java.lang.String node,
               java.lang.String cookie,
               int port)
        throws java.io.IOException
Throws:
java.io.IOException
Method Detail

pid

public OtpErlangPid pid()
Get the Erlang PID that will be used as the sender id in all "anonymous" messages sent by this node. Anonymous messages are those sent via send methods in OtpConnection that do not specify a sender.

Returns:
the Erlang PID that will be used as the sender id in all anonymous messages sent by this node.

publishPort

public boolean publishPort()
                    throws java.io.IOException
Make public the information needed by remote nodes that may wish to connect to this one. This method establishes a connection to the Erlang port mapper (Epmd) and registers the server node's name and port so that remote nodes are able to connect.

This method will fail if an Epmd process is not running on the localhost. See the Erlang documentation for information about starting Epmd.

Note that once this method has been called, the node is expected to be available to accept incoming connections. For that reason you should make sure that you call accept() shortly after calling publishPort(). When you no longer intend to accept connections you should call unPublishPort().

Returns:
true if the operation was successful, false if the node was already registered.
Throws:
java.io.IOException - if the port mapper could not be contacted.

unPublishPort

public void unPublishPort()
Unregister the server node's name and port number from the Erlang port mapper, thus preventing any new connections from remote nodes.


accept

public OtpConnection accept()
                     throws java.io.IOException,
                            OtpAuthException
Accept an incoming connection from a remote node. A call to this method will block until an incoming connection is at least attempted.

Returns:
a connection to a remote node.
Throws:
java.io.IOException - if a remote node attempted to connect but no common protocol was found.
OtpAuthException - if a remote node attempted to connect, but was not authorized to connect.

connect

public OtpConnection connect(OtpPeer other)
                      throws java.io.IOException,
                             java.net.UnknownHostException,
                             OtpAuthException
Open a connection to a remote node.

Parameters:
other - the remote node to which you wish to connect.
Returns:
a connection to the remote node.
Throws:
java.net.UnknownHostException - if the remote host could not be found.
java.io.IOException - if it was not possible to connect to the remote node.
OtpAuthException - if the connection was refused by the remote node.