| /* |
| * Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.rmi.transport.tcp; |
| |
| import java.io.*; |
| import java.net.Socket; |
| import java.rmi.*; |
| import sun.rmi.runtime.Log; |
| import sun.rmi.transport.*; |
| |
| public class TCPConnection implements Connection { |
| |
| private Socket socket; |
| private Channel channel; |
| private InputStream in = null; |
| private OutputStream out = null; |
| private long expiration = Long.MAX_VALUE; |
| private long lastuse = Long.MIN_VALUE; |
| private long roundtrip = 5; // round-trip time for ping |
| |
| /** |
| * Constructor used for creating a connection to accept call |
| * (an input connection) |
| */ |
| TCPConnection(TCPChannel ch, Socket s, InputStream in, OutputStream out) |
| { |
| socket = s; |
| channel = ch; |
| this.in = in; |
| this.out = out; |
| } |
| |
| /** |
| * Constructor used by subclass when underlying input and output streams |
| * are already available. |
| */ |
| TCPConnection(TCPChannel ch, InputStream in, OutputStream out) |
| { |
| this(ch, null, in, out); |
| } |
| |
| /** |
| * Constructor used when socket is available, but not underlying |
| * streams. |
| */ |
| TCPConnection(TCPChannel ch, Socket s) |
| { |
| this(ch, s, null, null); |
| } |
| |
| /** |
| * Gets the output stream for this connection |
| */ |
| public OutputStream getOutputStream() throws IOException |
| { |
| if (out == null) |
| out = new BufferedOutputStream(socket.getOutputStream()); |
| return out; |
| } |
| |
| /** |
| * Release the output stream for this connection. |
| */ |
| public void releaseOutputStream() throws IOException |
| { |
| if (out != null) |
| out.flush(); |
| } |
| |
| /** |
| * Gets the input stream for this connection. |
| */ |
| public InputStream getInputStream() throws IOException |
| { |
| if (in == null) |
| in = new BufferedInputStream(socket.getInputStream()); |
| return in; |
| } |
| |
| |
| /** |
| * Release the input stream for this connection. |
| */ |
| public void releaseInputStream() |
| { |
| } |
| |
| /** |
| * Determine if this connection can be used for multiple operations. |
| * If the socket implements RMISocketInfo, then we can query it about |
| * this; otherwise, assume that it does provide a full-duplex |
| * persistent connection like java.net.Socket. |
| */ |
| public boolean isReusable() |
| { |
| return true; |
| } |
| |
| /** |
| * Set the expiration time of this connection. |
| * @param time The time at which the time out expires. |
| */ |
| void setExpiration(long time) |
| { |
| expiration = time; |
| } |
| |
| /** |
| * Set the timestamp at which this connection was last used successfully. |
| * The connection will be pinged for liveness if reused long after |
| * this time. |
| * @param time The time at which the connection was last active. |
| */ |
| void setLastUseTime(long time) |
| { |
| lastuse = time; |
| } |
| |
| /** |
| * Returns true if the timeout has expired on this connection; |
| * otherwise returns false. |
| * @param time The current time. |
| */ |
| boolean expired(long time) |
| { |
| return expiration <= time; |
| } |
| |
| /** |
| * Probes the connection to see if it still alive and connected to |
| * a responsive server. If the connection has been idle for too |
| * long, the server is pinged. ``Too long'' means ``longer than the |
| * last ping round-trip time''. |
| * <P> |
| * This method may misdiagnose a dead connection as live, but it |
| * will never misdiagnose a live connection as dead. |
| * @return true if the connection and server are recently alive |
| */ |
| public boolean isDead() |
| { |
| InputStream i; |
| OutputStream o; |
| |
| // skip ping if recently used within 1 RTT |
| long start = System.currentTimeMillis(); |
| if ((roundtrip > 0) && (start < lastuse + roundtrip)) |
| return (false); // still alive and warm |
| |
| // Get the streams |
| try { |
| i = getInputStream(); |
| o = getOutputStream(); |
| } catch (IOException e) { |
| return (true); // can't even get a stream, must be very dead |
| } |
| |
| // Write the ping byte and read the reply byte |
| int response = 0; |
| try { |
| o.write(TransportConstants.Ping); |
| o.flush(); |
| response = i.read(); |
| } catch (IOException ex) { |
| TCPTransport.tcpLog.log(Log.VERBOSE, "exception: ", ex); |
| TCPTransport.tcpLog.log(Log.BRIEF, "server ping failed"); |
| |
| return (true); // server failed the ping test |
| } |
| |
| if (response == TransportConstants.PingAck) { |
| // save most recent RTT for future use |
| roundtrip = (System.currentTimeMillis() - start) * 2; |
| // clock-correction may make roundtrip < 0; doesn't matter |
| return (false); // it's alive and 5-by-5 |
| } |
| |
| if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) { |
| TCPTransport.tcpLog.log(Log.BRIEF, |
| (response == -1 ? "server has been deactivated" : |
| "server protocol error: ping response = " + response)); |
| } |
| return (true); |
| } |
| |
| /** |
| * Close the connection. */ |
| public void close() throws IOException |
| { |
| TCPTransport.tcpLog.log(Log.BRIEF, "close connection"); |
| |
| if (socket != null) |
| socket.close(); |
| else { |
| in.close(); |
| out.close(); |
| } |
| } |
| |
| /** |
| * Returns the channel for this connection. |
| */ |
| public Channel getChannel() |
| { |
| return channel; |
| } |
| } |