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      protected CRaSHProcess(CRaSHSession crash, String request) {
040        this.crash = crash;
041        this.request = request;
042      }
043    
044      public void execute(ShellProcessContext processContext) {
045        ShellResponse resp;
046        thread = Thread.currentThread();
047        try {
048          resp = invoke(processContext);
049          if (Thread.interrupted()) {
050            throw new InterruptedException("Just a mere goto :-)");
051          }
052        } catch (InterruptedException e) {
053          resp = new ShellResponse.Cancelled();
054        } catch (Throwable t) {
055          resp = ShellResponse.internalError(t);
056        } finally {
057          thread = null;
058        }
059    
060        //
061        processContext.end(resp);
062    
063        //
064        if (resp instanceof ShellResponse.Error) {
065          ShellResponse.Error error = (ShellResponse.Error)resp;
066          Throwable t = error.getThrowable();
067          if (t != null) {
068            CRaSHSession.log.error("Error while evaluating request '" + request + "' " + error.getText(), t);
069          } else {
070            CRaSHSession.log.error("Error while evaluating request '" + request + "' " + error.getText());
071          }
072        }
073      }
074    
075      abstract ShellResponse invoke(ShellProcessContext context) throws InterruptedException;
076    
077      public void cancel() {
078        Thread t = thread;
079        if (t != null) {
080          t.interrupt();
081        }
082      }
083    }