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    
020    package org.crsh.vfs;
021    
022    import org.crsh.vfs.spi.FSDriver;
023    
024    import java.io.IOException;
025    
026    /**
027     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
028     * @version $Revision$
029     */
030    class Mount<H> {
031    
032      static <H> Mount<H> wrap(FSDriver<H> driver) {
033        return new Mount<H>(driver);
034      }
035    
036      /** . */
037      private final FSDriver<H> driver;
038    
039      /**
040       * Create a new mount
041       *
042       * @param driver the driver
043       * @throws NullPointerException if the driver is null
044       */
045      Mount(FSDriver<H> driver) throws NullPointerException {
046        if (driver == null) {
047          throw new NullPointerException("No null driver accepted");
048        }
049        this.driver = driver;
050      }
051    
052      Handle<H> getHandle(Path path) throws IOException {
053        H current = driver.root();
054        for (String name : path) {
055          H next = null;
056          for (H child : driver.children(current)) {
057            String childName = driver.name(child);
058            if (childName.equals(name)) {
059              next = child;
060              break;
061            }
062          }
063          if (next == null) {
064            return null;
065          } else {
066            current = next;
067          }
068        }
069        if (path.isDir() == driver.isDir(current)) {
070          return new Handle<H>(driver, current);
071        } else {
072          return null;
073        }
074      }
075    }