/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
namespace Lucene.Net.Store{
/// <summary>A Directory is a flat list of files. Files may be written once, when they
/// are created. Once a file is created it may only be opened for read, or
/// deleted. Random access is permitted both when reading and writing.
///
/// <p> Java's i/o APIs not used directly, but rather all i/o is
/// through this API. This permits things such as: <ul>
/// <li> implementation of RAM-based indices;
/// <li> implementation indices stored in a database, via JDBC;
/// <li> implementation of an index as a single file;
/// </ul>
///
/// </summary>
/// <author> Doug Cutting
/// </author>
public abstract class Directory
{
/// <summary>Returns an array of strings, one for each file in the directory. </summary>
public abstract System.String[] List();
/// <summary>Returns true iff a file with the given name exists. </summary>
public abstract bool FileExists(System.String name);
/// <summary>Returns the time the named file was last modified. </summary>
public abstract long FileModified(System.String name);
/// <summary>Set the modified time of an existing file to now. </summary>
public abstract void TouchFile(System.String name);
/// <summary>Removes an existing file in the directory. </summary>
public abstract void DeleteFile(System.String name);
/// <summary>Renames an existing file in the directory.
/// If a file already exists with the new name, then it is replaced.
/// This replacement should be atomic.
/// </summary>
public abstract void RenameFile(System.String from, System.String to);
/// <summary>Returns the length of a file in the directory. </summary>
public abstract long FileLength(System.String name);
/// <deprecated> use {@link #CreateOutput(String)}
/// </deprecated>
public virtual OutputStream createFile(System.String name)
{
return (OutputStream) CreateOutput(name);
}
/// <summary>Creates a new, empty file in the directory with the given name.
/// Returns a stream writing this file.
/// </summary>
public virtual IndexOutput CreateOutput(System.String name)
{
// default implementation for back compatibility
// this method should be abstract
return (IndexOutput) createFile(name);
}
/// <deprecated> use {@link #OpenInput(String)}
/// </deprecated>
public virtual InputStream OpenFile(System.String name)
{
return (InputStream) OpenInput(name);
}
/// <summary>Returns a stream reading an existing file. </summary>
public virtual IndexInput OpenInput(System.String name)
{
// default implementation for back compatibility
// this method should be abstract
return (IndexInput) OpenFile(name);
}
/// <summary>Construct a {@link Lock}.</summary>
/// <param name="name">the name of the lock file
/// </param>
public abstract Lock MakeLock(System.String name);
/// <summary>Closes the store. </summary>
public abstract void Close();
}
}
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