The basis of cluster support for Presents servers. All servers in a cluster

make connections to other servers in the cluster and can exchange events (in a
limited fashion).

This is different than Liz's project wherein servers share an oid space and one
can interchangably work with distributed objects from any server. This package
provides a means by which certain services (by default, presence and chat) can
be communicated between servers to allow communication between players
scattered around a bunch of otherwise independent server instances.

This is less general purpose but also less likely to encourage people to write
code that tightly couples multiple servers and then falls over because it
generates gobs of network traffic as events are flung willy nilly behind the
scenes.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4238 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/peer/server/persist/NodeRecord.java

@@ -0,0 +1,65 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2006 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.presents.peer.server.persist;
+
+import java.sql.Timestamp;
+
+import com.samskivert.util.StringUtil;
+
+/**
+ * Contains information on an active node in a Presents server cluster.
+ */
+public class NodeRecord
+{
+    /** The unique name assigned to this node. */
+    public String nodeName;
+
+    /** The DNS name of the server running this node. */
+    public String hostName;
+
+    /** The port on which to connect to this node. */
+    public int port;
+
+    /** The last time this node has reported in. */
+    public Timestamp lastUpdated;
+
+    /** Used to create a blank instance when loading from the database. */
+    public NodeRecord ()
+    {
+    }
+
+    /** Creates a record for the specified node. */
+    public NodeRecord (String nodeName, String hostName, int port)
+    {
+        this.nodeName = nodeName;
+        this.hostName = hostName;
+        this.port = port;
+    }
+
+    /**
+     * Generates a string representation of this instance.
+     */
+    public String toString ()
+    {
+        return StringUtil.fieldsToString(this);
+    }
+}

src/java/com/threerings/presents/peer/server/persist/NodeRepository.java

@@ -0,0 +1,97 @@
+//
+// $Id$
+//
+// Narya library - tools for developing networked games
+// Copyright (C) 2002-2006 Three Rings Design, Inc., All Rights Reserved
+// http://www.threerings.net/code/narya/
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.threerings.presents.peer.server.persist;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.ArrayList;
+
+import com.samskivert.io.PersistenceException;
+
+import com.samskivert.jdbc.ConnectionProvider;
+import com.samskivert.jdbc.DatabaseLiaison;
+import com.samskivert.jdbc.JDBCUtil;
+import com.samskivert.jdbc.JORARepository;
+import com.samskivert.jdbc.jora.Table;
+
+/**
+ * Used to share information on active nodes in a Presents server cluster.
+ */
+public class NodeRepository extends JORARepository
+{
+    /** The database identifier used when establishing a database connection.
+     * This value being <code>nodedb</code>. */
+    public static final String NODE_DB_IDENT = "nodedb";
+
+    /**
+     * Constructs a new repository with the specified connection provider.
+     *
+     * @param conprov the connection provider via which we will obtain our
+     * database connection.
+     */
+    public NodeRepository (ConnectionProvider conprov)
+        throws PersistenceException
+    {
+        super(conprov, NODE_DB_IDENT);
+    }
+
+    /**
+     * Returns a list of all nodes registered in the repository.
+     */
+    public ArrayList<NodeRecord> loadNodes ()
+        throws PersistenceException
+    {
+        return loadAll(_ntable, "");
+    }
+
+    /**
+     * Updates the supplied node record, inserting it into the database if
+     * necessary.
+     */
+    public void updateNode (NodeRecord record)
+        throws PersistenceException
+    {
+        store(_ntable, record);
+    }
+
+    @Override // documentation inherited
+    protected void migrateSchema (Connection conn, DatabaseLiaison liaison)
+        throws SQLException, PersistenceException
+    {
+        JDBCUtil.createTableIfMissing(conn, "NODES", new String[] {
+            "NODE_NAME VARCHAR(64) NOT NULL",
+            "HOST_NAME VARCHAR(64) NOT NULL",
+            "PORT INTEGER NOT NULL",
+            "LAST_UPDATED TIMESTAMP NOT NULL",
+            "PRIMARY KEY (NODE_NAME)",
+        }, "");
+    }
+
+    @Override // documentation inherited
+    protected void createTables ()
+    {
+	_ntable = new Table<NodeRecord>(
+            NodeRecord.class, "NODES", "NODE_NAME", true);
+    }
+
+    protected Table<NodeRecord> _ntable;
+}