001    /*
002     * Copyright (C) 2012 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.spi;
021    
022    import java.io.IOException;
023    import java.io.InputStream;
024    import java.util.Iterator;
025    
026    /**
027     * <p>A driver for the file system, this interface is the Service Provider Interface (SPI) part
028     * provided by CRaSH.</p>
029     *
030     * <p>The driver works with handles which are opaque objects that model a path in the file system,
031     * an handle can represent a file or a directory and is considered as non modifiable from the file
032     * system perspective.</p>
033     *
034     * @param <H> the handle generic type.
035     */
036    public interface FSDriver<H> {
037    
038      /**
039       * Returns the root handle.
040       *
041       * @return the root handle
042       * @throws IOException any io exception
043       */
044      H root() throws IOException;
045    
046      /**
047       * Returns the name of the handle.
048       *
049       * @param handle the handle
050       * @return the handle name
051       * @throws IOException any io exception
052       */
053      String name(H handle) throws IOException;
054    
055      /**
056       * Returns true if the handle represent a directory.
057       *
058       * @param handle the handle
059       * @return true if the handle is a directory, false otherwise
060       * @throws IOException any io exception
061       */
062      boolean isDir(H handle) throws IOException;
063    
064      /**
065       * Return the specific child of a directory handle, null should be returned if no such
066       * child exist.
067       *
068       * @param handle the directory handle
069       * @param name the child name
070       * @return the specified child
071       * @throws IOException any io exception
072       */
073      H child(H handle, String name) throws IOException;
074    
075      /**
076       * Returns an iterable over the children of of a specific directory handle.
077       *
078       * @param handle the directory handle
079       * @return the children as an iterable
080       * @throws IOException any io exception
081       */
082      Iterable<H> children(H handle) throws IOException;
083    
084      /**
085       * Return the last modified date timestamp of an handle.
086       *
087       * @param handle the handle
088       * @return the last modified timestamp
089       * @throws IOException any io exception
090       */
091      long getLastModified(H handle) throws IOException;
092    
093      /**
094       * Return an iterator over the resources represented by the specified file handle.
095       *
096       * @param handle the file handle
097       * @return the iterator
098       * @throws IOException any io exception
099       */
100      Iterator<InputStream> open(H handle) throws IOException;
101    
102    }