001    /*
002     * Copyright (C) 2010 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    package org.crsh.shell.impl;
020    
021    import org.crsh.shell.ShellProcess;
022    import org.crsh.shell.ShellProcessContext;
023    import org.crsh.shell.ShellResponse;
024    
025    /**
026     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
027     */
028    abstract class CRaSHProcess implements ShellProcess {
029    
030      /** . */
031      protected final CRaSHSession crash;
032    
033      /** . */
034      protected final String request;
035    
036      /** . */
037      private volatile Thread thread;
038    
039      /** . */
040      private volatile boolean cancelled;
041    
042      protected CRaSHProcess(CRaSHSession crash, String request) {
043        this.crash = crash;
044        this.request = request;
045      }
046    
047      public void execute(ShellProcessContext processContext) {
048        ShellResponse resp;
049        thread = Thread.currentThread();
050        try {
051          try {
052            resp = doInvoke(processContext);
053            if (Thread.interrupted() || cancelled) {
054              throw new InterruptedException("like a goto");
055            }
056          }
057          catch (InterruptedException e) {
058            resp = ShellResponse.cancelled();
059          }
060        } catch (Throwable t) {
061          resp = ShellResponse.internalError(t);
062        } finally {
063          thread = null;
064        }
065    
066        //
067        processContext.end(resp);
068    
069        //
070        if (resp instanceof ShellResponse.Error) {
071          ShellResponse.Error error = (ShellResponse.Error)resp;
072          Throwable t = error.getThrowable();
073          if (t != null) {
074            CRaSHSession.log.error("Error while evaluating request '" + request + "' " + error.getText(), t);
075          } else {
076            CRaSHSession.log.error("Error while evaluating request '" + request + "' " + error.getText());
077          }
078        }
079      }
080    
081      abstract ShellResponse doInvoke(ShellProcessContext context) throws InterruptedException;
082    
083      public void cancel() {
084        Thread t = thread;
085        if (t != null) {
086          t.interrupt();
087        }
088        cancelled = true;
089      }
090    }