beagled/Lucene.Net/Store/Directory.cs

   1 /*
   2  * Copyright 2004 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 using System;
  18
  19 namespace Lucene.Net.Store
  20 {
  21
  22         /// <summary>A Directory is a flat list of files.  Files may be written once, when they
  23         /// are created.  Once a file is created it may only be opened for read, or
  24         /// deleted.  Random access is permitted both when reading and writing.
  25         ///
  26         /// <p> Java's i/o APIs not used directly, but rather all i/o is
  27         /// through this API.  This permits things such as: <ul>
  28         /// <li> implementation of RAM-based indices;
  29         /// <li> implementation indices stored in a database, via JDBC;
  30         /// <li> implementation of an index as a single file;
  31         /// </ul>
  32         ///
  33         /// </summary>
  34         /// <author>  Doug Cutting
  35         /// </author>
  36         public abstract class Directory
  37         {
  38                 /// <summary>Returns an array of strings, one for each file in the directory. </summary>
  39                 public abstract System.String[] List();
  40
  41                 /// <summary>Returns true iff a file with the given name exists. </summary>
  42                 public abstract bool FileExists(System.String name);
  43
  44                 /// <summary>Returns the time the named file was last modified. </summary>
  45                 public abstract long FileModified(System.String name);
  46
  47                 /// <summary>Set the modified time of an existing file to now. </summary>
  48                 public abstract void  TouchFile(System.String name);
  49
  50                 /// <summary>Removes an existing file in the directory. </summary>
  51                 public abstract void  DeleteFile(System.String name);
  52
  53                 /// <summary>Renames an existing file in the directory.
  54                 /// If a file already exists with the new name, then it is replaced.
  55                 /// This replacement should be atomic.
  56                 /// </summary>
  57                 public abstract void  RenameFile(System.String from, System.String to);
  58
  59                 /// <summary>Returns the length of a file in the directory. </summary>
  60                 public abstract long FileLength(System.String name);
  61
  62                 /// <deprecated> use {@link #CreateOutput(String)}
  63                 /// </deprecated>
  64                 public virtual OutputStream createFile(System.String name)
  65                 {
  66                         return (OutputStream) CreateOutput(name);
  67                 }
  68
  69                 /// <summary>Creates a new, empty file in the directory with the given name.
  70                 /// Returns a stream writing this file.
  71                 /// </summary>
  72                 public virtual IndexOutput CreateOutput(System.String name)
  73                 {
  74                         // default implementation for back compatibility
  75                         // this method should be abstract
  76                         return (IndexOutput) createFile(name);
  77                 }
  78
  79                 /// <deprecated> use {@link #OpenInput(String)}
  80                 /// </deprecated>
  81                 public virtual InputStream OpenFile(System.String name)
  82                 {
  83                         return (InputStream) OpenInput(name);
  84                 }
  85
  86                 /// <summary>Returns a stream reading an existing file. </summary>
  87                 public virtual IndexInput OpenInput(System.String name)
  88                 {
  89                         // default implementation for back compatibility
  90                         // this method should be abstract
  91                         return (IndexInput) OpenFile(name);
  92                 }
  93
  94                 /// <summary>Construct a {@link Lock}.</summary>
  95                 /// <param name="name">the name of the lock file
  96                 /// </param>
  97                 public abstract Lock MakeLock(System.String name);
  98
  99                 /// <summary>Closes the store. </summary>
 100                 public abstract void  Close();
 101         }
 102 }