Class Directory

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.

.NET's i/o APIs not used directly, but rather all i/o is through this API. This permits things such as:

• implementation of RAM-based indices;
• implementation indices stored in a database;
• implementation of an index as a single file;

Directory locking is implemented by an instance of LockFactory, and can be changed for each Directory instance using SetLockFactory(LockFactory).

Inheritance

System.Object

Directory

BaseDirectory

FilterDirectory

NRTCachingDirectory

Implements

System.IDisposable

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

Namespace: Lucene.Net.Store

Assembly: Lucene.Net.dll

Syntax

public abstract class Directory : IDisposable

Properties

LockFactory

Get the LockFactory that this Directory instance is using for its locking implementation. Note that this may be null for Directory implementations that provide their own locking implementation.

Declaration

public abstract LockFactory LockFactory { get; }

Property Value

Type	Description
LockFactory

Methods

ClearLock(String)

Attempt to clear (forcefully unlock and remove) the specified lock. Only call this at a time when you are certain this lock is no longer in use.

Declaration

public abstract void ClearLock(string name)

Parameters

Type	Name	Description
System.String	name	name of the lock to be cleared.

Copy(Directory, String, String, IOContext)

Copies the file src to Directory to under the new file name dest.

If you want to copy the entire source directory to the destination one, you can do so like this:

Directory to; // the directory to copy to
foreach (string file in dir.ListAll()) {
    dir.Copy(to, file, newFile, IOContext.DEFAULT); // newFile can be either file, or a new name
}

NOTE: this method does not check whether dest exist and will overwrite it if it does.

Declaration

public virtual void Copy(Directory to, string src, string dest, IOContext context)

Parameters

Type	Name	Description
Directory	to
System.String	src
System.String	dest
IOContext	context

CreateOutput(String, IOContext)

Creates a new, empty file in the directory with the given name. Returns a stream writing this file.

Declaration

public abstract IndexOutput CreateOutput(string name, IOContext context)

Parameters

Type	Name	Description
System.String	name
IOContext	context

Returns

Type	Description
IndexOutput

CreateSlicer(String, IOContext)

Creates an Directory.IndexInputSlicer for the given file name. Directory.IndexInputSlicer allows other Directory implementations to efficiently open one or more sliced IndexInput instances from a single file handle. The underlying file handle is kept open until the Directory.IndexInputSlicer is closed.

Throws System.IO.FileNotFoundException if the file does not exist.

Note

This API is for internal purposes only and might change in incompatible ways in the next release.

Note

This API is experimental and might change in incompatible ways in the next release.

Declaration

public virtual Directory.IndexInputSlicer CreateSlicer(string name, IOContext context)

Parameters

Type	Name	Description
System.String	name
IOContext	context

Returns

Type	Description
Directory.IndexInputSlicer

Exceptions

Type	Condition
System.IO.IOException	if an System.IO.IOException occurs

DeleteFile(String)

Removes an existing file in the directory.

Declaration

public abstract void DeleteFile(string name)

Parameters

Type	Name	Description
System.String	name

Dispose()

Disposes the store.

Declaration

public void Dispose()

Dispose(Boolean)

Disposes the store.

Declaration

protected abstract void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing

EnsureOpen()

Declaration

protected virtual void EnsureOpen()

Exceptions

Type	Condition
System.ObjectDisposedException	if this Directory is closed

FileExists(String)

Returns true iff a file with the given name exists.

Declaration

[Obsolete("this method will be removed in 5.0")]
public abstract bool FileExists(string name)

Parameters

Type	Name	Description
System.String	name

Returns

Type	Description
System.Boolean

FileLength(String)

Returns the length of a file in the directory. this method follows the following contract:

Declaration

public abstract long FileLength(string name)

Parameters

Type	Name	Description
System.String	name	the name of the file for which to return the length.

Returns

Type	Description
System.Int64

Exceptions

Type	Condition
System.IO.IOException	if there was an IO error while retrieving the file's length.

GetLockID()

Return a string identifier that uniquely differentiates this Directory instance from other Directory instances. This ID should be the same if two Directory instances (even in different AppDomains and/or on different machines) are considered "the same index". This is how locking "scopes" to the right index.

Declaration

public virtual string GetLockID()

Returns

Type	Description
System.String

ListAll()

Returns an array of strings, one for each file in the directory.

Declaration

public abstract string[] ListAll()

Returns

Type	Description
System.String[]

Exceptions

Type	Condition
System.IO.DirectoryNotFoundException	if the directory is not prepared for any write operations (such as CreateOutput(String, IOContext)).
System.IO.IOException	in case of other IO errors

MakeLock(String)

Construct a Lock.

Declaration

public abstract Lock MakeLock(string name)

Parameters

Type	Name	Description
System.String	name	the name of the lock file

Returns

Type	Description
Lock

OpenChecksumInput(String, IOContext)

Returns a stream reading an existing file, computing checksum as it reads

Declaration

public virtual ChecksumIndexInput OpenChecksumInput(string name, IOContext context)

Parameters

Type	Name	Description
System.String	name
IOContext	context

Returns

Type	Description
ChecksumIndexInput

OpenInput(String, IOContext)

Returns a stream reading an existing file, with the specified read buffer size. The particular Directory implementation may ignore the buffer size. Currently the only Directory implementations that respect this parameter are FSDirectory and CompoundFileDirectory.

Throws System.IO.FileNotFoundException if the file does not exist.

Declaration

public abstract IndexInput OpenInput(string name, IOContext context)

Parameters

Type	Name	Description
System.String	name
IOContext	context

Returns

Type	Description
IndexInput

SetLockFactory(LockFactory)

Set the LockFactory that this Directory instance should use for its locking implementation. Each * instance of LockFactory should only be used for one directory (ie, do not share a single instance across multiple Directories).

Declaration

public abstract void SetLockFactory(LockFactory lockFactory)

Parameters

Type	Name	Description
LockFactory	lockFactory	instance of LockFactory.

Sync(ICollection<String>)

Ensure that any writes to these files are moved to stable storage. Lucene uses this to properly commit changes to the index, to prevent a machine/OS crash from corrupting the index.

NOTE: Clients may call this method for same files over and over again, so some impls might optimize for that. For other impls the operation can be a noop, for various reasons.

Declaration

public abstract void Sync(ICollection<string> names)

Parameters

Type	Name	Description
System.Collections.Generic.ICollection<System.String>	names

ToString()

Declaration

public override string ToString()

Returns

Type	Description
System.String

Overrides

System.Object.ToString()

Implements

System.IDisposable