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.command;
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        ClassLoader previous = crash.setCRaSHLoader();
049        try {
050          ShellResponse resp;
051          thread = Thread.currentThread();
052    
053          //
054          if (crash.user != null) {
055            String userName = crash.user != null ? crash.user.getName() : "unauthenticated";
056            CRaSHSession.accessLog.debug("User " + userName + " executes " + request);
057          }
058    
059          //
060          try {
061            try {
062              resp = doInvoke(processContext);
063              if (Thread.interrupted() || cancelled) {
064                throw new InterruptedException("like a goto");
065              }
066            }
067            catch (InterruptedException e) {
068              resp = ShellResponse.cancelled();
069            }
070          } catch (Throwable t) {
071            resp = ShellResponse.internalError("Unexpected error when executing process", t);
072          } finally {
073            thread = null;
074          }
075    
076          //
077          processContext.end(resp);
078    
079          //
080          if (resp instanceof ShellResponse.Error) {
081            ShellResponse.Error error = (ShellResponse.Error)resp;
082            Throwable t = error.getThrowable();
083            if (t != null) {
084              CRaSHSession.log.error("Error while evaluating request '" + request + "' " + error.getText(), t);
085            } else {
086              CRaSHSession.log.error("Error while evaluating request '" + request + "' " + error.getText());
087            }
088          }
089        }
090        finally {
091          crash.setPreviousLoader(previous);
092        }
093      }
094    
095      abstract ShellResponse doInvoke(ShellProcessContext context) throws InterruptedException;
096    
097      public void cancel() {
098        ClassLoader previous = crash.setCRaSHLoader();
099        try {
100          Thread t = thread;
101          if (t != null) {
102            t.interrupt();
103          }
104          cancelled = true;
105        }
106        finally {
107          crash.setPreviousLoader(previous);
108        }
109      }
110    }