Lucene.Net/Store/Directory.cs

   1 using System;
   2
   3 namespace Lucene.Net.Store
   4 {
   5         /* ====================================================================
   6          * The Apache Software License, Version 1.1
   7          *
   8          * Copyright (c) 2001 The Apache Software Foundation.  All rights
   9          * reserved.
  10          *
  11          * Redistribution and use in source and binary forms, with or without
  12          * modification, are permitted provided that the following conditions
  13          * are met:
  14          *
  15          * 1. Redistributions of source code must retain the above copyright
  16          *    notice, this list of conditions and the following disclaimer.
  17          *
  18          * 2. Redistributions in binary form must reproduce the above copyright
  19          *    notice, this list of conditions and the following disclaimer in
  20          *    the documentation and/or other materials provided with the
  21          *    distribution.
  22          *
  23          * 3. The end-user documentation included with the redistribution,
  24          *    if any, must include the following acknowledgment:
  25          *       "This product includes software developed by the
  26          *        Apache Software Foundation (http://www.apache.org/)."
  27          *    Alternately, this acknowledgment may appear in the software itself,
  28          *    if and wherever such third-party acknowledgments normally appear.
  29          *
  30          * 4. The names "Apache" and "Apache Software Foundation" and
  31          *    "Apache Lucene" must not be used to endorse or promote products
  32          *    derived from this software without prior written permission. For
  33          *    written permission, please contact apache@apache.org.
  34          *
  35          * 5. Products derived from this software may not be called "Apache",
  36          *    "Apache Lucene", nor may "Apache" appear in their name, without
  37          *    prior written permission of the Apache Software Foundation.
  38          *
  39          * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  40          * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  41          * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  42          * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  43          * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44          * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  45          * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  46          * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  47          * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  48          * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  49          * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50          * SUCH DAMAGE.
  51          * ====================================================================
  52          *
  53          * This software consists of voluntary contributions made by many
  54          * individuals on behalf of the Apache Software Foundation.  For more
  55          * information on the Apache Software Foundation, please see
  56          * <http://www.apache.org/>.
  57          */
  58
  59         /// <summary>
  60         /// A Directory is a flat list of files.  Files may be written once, when they
  61         /// are created.  Once a file is created it may only be opened for read, or
  62         /// deleted.  Random access is permitted both when reading and writing.
  63         ///
  64         /// <p> Java's i/o APIs not used directly, but rather all i/o is
  65         /// through this API.  This permits things such as: </p>
  66         /// <ul>
  67         ///             <li> implementation of RAM-based indices;</li>
  68         ///             <li> implementation indices stored in a database, via JDBC;</li>
  69         ///             <li> implementation of an index as a single file;</li>
  70         /// </ul>
  71         /// </summary>
  72         /// <author>Doug Cutting</author>
  73         public abstract class Directory
  74         {
  75                 /// <summary>
  76                 /// Returns an array of strings, one for each file in the directory.
  77                 /// </summary>
  78                 /// <returns></returns>
  79                 public abstract String[] List();
  80
  81                 /// <summary>
  82                 /// Returns true iff a file with the given name exists.
  83                 /// </summary>
  84                 /// <param name="name"></param>
  85                 /// <returns></returns>
  86                 public abstract bool FileExists(String name);
  87
  88                 /// <summary>
  89                 /// Returns the time the named file was last modified.
  90                 /// </summary>
  91                 /// <param name="name"></param>
  92                 /// <returns></returns>
  93                 public abstract long FileModified(String name)  ;
  94
  95                 /// <summary>
  96                 /// Set the modified time of an existing file to now.
  97                 /// </summary>
  98                 /// <param name="name"></param>
  99                 public abstract void TouchFile(String name);
 100
 101                 /// <summary>
 102                 /// Removes an existing file in the directory.
 103                 /// </summary>
 104                 /// <param name="name"></param>
 105                 public abstract void DeleteFile(String name);
 106
 107                 /// <summary>
 108                 /// Renames an existing file in the directory.
 109                 /// If a file already exists with the new name, then it is replaced.
 110                 /// This replacement should be atomic.
 111                 /// </summary>
 112                 /// <param name="from"></param>
 113                 /// <param name="to"></param>
 114                 public abstract void RenameFile(String from, String to);
 115
 116                 /// <summary>
 117                 /// Returns the length of a file in the directory.
 118                 /// </summary>
 119                 /// <param name="name"></param>
 120                 /// <returns></returns>
 121                 public abstract long FileLength(String name);
 122
 123                 /// <summary>
 124                 /// Creates a new, empty file in the directory with the given name.
 125                 /// Returns a stream writing this file.
 126                 /// </summary>
 127                 /// <param name="name"></param>
 128                 /// <returns></returns>
 129                 public abstract OutputStream CreateFile(String name);
 130
 131                 /// <summary>
 132                 /// Returns a stream reading an existing file.
 133                 /// </summary>
 134                 /// <param name="name"></param>
 135                 /// <returns></returns>
 136                 public abstract InputStream OpenFile(String name);
 137
 138                 /// <summary>
 139                 /// Construct a Lock.
 140                 /// </summary>
 141                 /// <param name="name">the name of the lock file</param>
 142                 /// <returns></returns>
 143                 public abstract Lock MakeLock(String name);
 144
 145                 /// <summary>
 146                 /// Closes the store.
 147                 /// </summary>
 148                 public abstract void Close();
 149         }
 150 }