/* * %CopyrightBegin% * * Copyright Ericsson AB 2000-2009. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * %CopyrightEnd% */ package com.ericsson.otp.erlang; import java.io.IOException; import java.net.UnknownHostException; /** * 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 {@link #publishPort()}. *

* *
 * OtpSelf self = new OtpSelf("client", "authcookie"); // identify self
 * OtpPeer other = new OtpPeer("server"); // identify peer
 *
 * OtpConnection conn = self.connect(other); // connect to peer
 * 
* */ public class OtpSelf extends OtpLocalNode { private final OtpServerTransport sock; private final OtpErlangPid pid; /** *

* 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. *

* * @param node * the name of this node. * * @exception IOException * in case of server transport failure * */ public OtpSelf(final String node) throws IOException { this(node, defaultCookie, 0); } /** *

* Create a self node using the default cookie and custom transport factory. * 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. *

* * @param node * the name of this node. * * @param transportFactory * the transport factory to use when creating connections. * * @exception IOException * in case of server transport failure * */ public OtpSelf(final String node, final OtpTransportFactory transportFactory) throws IOException { this(node, defaultCookie, 0, transportFactory); } /** * Create a self node. * * @param node * the name of this node. * * @param cookie * the authorization cookie that will be used by this node when * it communicates with other nodes. * * @exception IOException * in case of server transport failure */ public OtpSelf(final String node, final String cookie) throws IOException { this(node, cookie, 0); } /** * Create a self node. * * @param node * the name of this node. * * @param cookie * the authorization cookie that will be used by this node when * it communicates with other nodes. * * @param transportFactory * the transport factory to use when creating connections. * * @exception IOException * in case of server transport failure */ public OtpSelf(final String node, final String cookie, final OtpTransportFactory transportFactory) throws IOException { this(node, cookie, 0, transportFactory); } /** * Create a self node. * * @param node * the name of this node. * * @param cookie * the authorization cookie that will be used by this node when * it communicates with other nodes. * * @param port * the port number you wish to use for incoming connections. * Specifying 0 lets the system choose an available port. * * @exception IOException * in case of server transport failure */ public OtpSelf(final String node, final String cookie, final int port) throws IOException { super(node, cookie); sock = createServerTransport(port); if (port != 0) { this.port = port; } else { this.port = sock.getLocalPort(); } pid = createPid(); } /** * Create a self node. * * @param node * the name of this node. * * @param cookie * the authorization cookie that will be used by this node when * it communicates with other nodes. * * @param port * the port number you wish to use for incoming connections. * Specifying 0 lets the system choose an available port. * * @param transportFactory * the transport factory to use when creating connections. * * @exception IOException * in case of server transport failure */ public OtpSelf(final String node, final String cookie, final int port, final OtpTransportFactory transportFactory) throws IOException { super(node, cookie, transportFactory); sock = createServerTransport(port); if (port != 0) { this.port = port; } else { this.port = sock.getLocalPort(); } pid = createPid(); } /** * 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 {@link OtpConnection OtpConnection} that do not specify a * sender. * * @return the Erlang PID that will be used as the sender id in all * anonymous messages sent by this node. */ public OtpErlangPid pid() { return pid; } /** * 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 {@link #accept()} shortly after calling * {@link #publishPort()}. When you no longer intend to accept connections * you should call {@link #unPublishPort()}. * * @return true if the operation was successful, false if the node was * already registered. * * @exception java.io.IOException * if the port mapper could not be contacted. */ public boolean publishPort() throws IOException { if (getEpmd() != null) { return false; // already published } OtpEpmd.publishPort(this); return getEpmd() != null; } /** * Unregister the server node's name and port number from the Erlang port * mapper, thus preventing any new connections from remote nodes. */ public void unPublishPort() { // unregister with epmd OtpEpmd.unPublishPort(this); // close the local descriptor (if we have one) try { if (super.epmd != null) { super.epmd.close(); } } catch (final IOException e) {/* ignore close errors */ } super.epmd = null; } /** * Accept an incoming connection from a remote node. A call to this method * will block until an incoming connection is at least attempted. * * @return a connection to a remote node. * * @exception java.io.IOException * if a remote node attempted to connect but no common * protocol was found. * * @exception OtpAuthException * if a remote node attempted to connect, but was not * authorized to connect. */ public OtpConnection accept() throws IOException, OtpAuthException { OtpTransport newsock = null; while (true) { try { newsock = sock.accept(); return new OtpConnection(this, newsock); } catch (final IOException e) { try { if (newsock != null) { newsock.close(); } } catch (final IOException f) {/* ignore close errors */ } throw e; } } } /** * Open a connection to a remote node. * * @param other * the remote node to which you wish to connect. * * @return a connection to the remote node. * * @exception java.net.UnknownHostException * if the remote host could not be found. * * @exception java.io.IOException * if it was not possible to connect to the remote node. * * @exception OtpAuthException * if the connection was refused by the remote node. */ public OtpConnection connect(final OtpPeer other) throws IOException, UnknownHostException, OtpAuthException { return new OtpConnection(this, other); } }