content: /*
   * Copyright (c) 2014, 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 openjdk.tools.sjavac.server;
  
  import openjdk.tools.sjavac.Log;
  
  import java.io.IOException;
  import java.util.Timer;
  import java.util.TimerTask;
  
  /**
   * Monitors the presence of a port file and shuts down the given SjavacServer
   * whenever the port file is deleted or invalidated.
   *
   * TODO: JDK-8046882
   *
   *  <p><b>This is NOT part of any supported API.
   *  If you write code that depends on this, you do so at your own risk.
   *  This code and its internal interfaces are subject to change or
   *  deletion without notice.</b>
   */
  public class PortFileMonitor {
  
      // Check if the portfile is gone, every 5 seconds.
      private final static int CHECK_PORTFILE_INTERVAL = 5000;
  
      final private Timer timer = new Timer();
      final private PortFile portFile;
      final private SjavacServer server;
  
      public PortFileMonitor(PortFile portFile,
                             SjavacServer server) {
          this.portFile = portFile;
          this.server = server;
      }
  
      public void start() {
          Log log = Log.get();
          TimerTask shutdownCheck = new TimerTask() {
              public void run() {
                  Log.setLogForCurrentThread(log);
                  Log.debug("Checking port file status...");
                  try {
                      if (!portFile.exists()) {
                          // Time to quit because the portfile was deleted by another
                          // process, probably by the makefile that is done building.
                          server.shutdown("Quitting because portfile was deleted!");
                      } else if (portFile.markedForStop()) {
                          // Time to quit because another process touched the file
                          // server.port.stop to signal that the server should stop.
                          // This is necessary on some operating systems that lock
                          // the port file hard!
                          server.shutdown("Quitting because a portfile.stop file was found!");
                      } else if (!portFile.stillMyValues()) {
                          // Time to quit because another build has started.
                          server.shutdown("Quitting because portfile is now owned by another javac server!");
                      }
                  } catch (IOException e) {
                      Log.error("IOException caught in PortFileMonitor.");
                      Log.debug(e);
                  } catch (InterruptedException e) {
                      Thread.currentThread().interrupt();
                      Log.error(e);
                  }
              }
          };
  
          timer.schedule(shutdownCheck, 0, CHECK_PORTFILE_INTERVAL);
      }
  
      public void shutdown() {
          timer.cancel();
      }
  }
  