org.apache.lucene.store

Class Directory

java.lang.Object
- org.apache.lucene.store.Directory

Known Direct Subclasses:: FSDirectory, RAMDirectory

public abstract class Directory

extends Object

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.

Java'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, via JDBC;
implementation of an index as a single file;

Author:: Doug Cutting

Method Summary
`abstract void`	`close()` Closes the store.
`OutputStream`	`createFile(String name)` Deprecated. use `createOutput(String)`
`IndexOutput`	`createOutput(String name)` Creates a new, empty file in the directory with the given name.
`abstract void`	`deleteFile(String name)` Removes an existing file in the directory.
`abstract boolean`	`fileExists(String name)` Returns true iff a file with the given name exists.
`abstract long`	`fileLength(String name)` Returns the length of a file in the directory.
`abstract long`	`fileModified(String name)` Returns the time the named file was last modified.
`abstract String[]`	`list()` Returns an array of strings, one for each file in the directory.
`abstract Lock`	`makeLock(String name)` Construct a `Lock`.
`InputStream`	`openFile(String name)` Deprecated. use `openInput(String)`
`IndexInput`	`openInput(String name)` Returns a stream reading an existing file.
`abstract void`	`renameFile(String from, String to)` Renames an existing file in the directory.
`abstract void`	`touchFile(String name)` Set the modified time of an existing file to now.

close

public abstract void close()
            throws IOException

Closes the store.

createFile

public OutputStream createFile(String name)
            throws IOException

Deprecated. use createOutput(String)

createOutput

public IndexOutput createOutput(String name)
            throws IOException

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

deleteFile

public abstract void deleteFile(String name)
            throws IOException

Removes an existing file in the directory.

fileExists

public abstract boolean fileExists(String name)
            throws IOException

Returns true iff a file with the given name exists.

fileLength

public abstract long fileLength(String name)
            throws IOException

Returns the length of a file in the directory.

fileModified

public abstract long fileModified(String name)
            throws IOException

Returns the time the named file was last modified.

list

public abstract String[] list()
            throws IOException

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

makeLock

public abstract Lock makeLock(String name)

Construct a Lock.
Parameters:
name - the name of the lock file

openFile

public InputStream openFile(String name)
            throws IOException

Deprecated. use openInput(String)

openInput

public IndexInput openInput(String name)
            throws IOException

Returns a stream reading an existing file.

renameFile

public abstract void renameFile(String from,
                                String to)
            throws IOException

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.

touchFile

public abstract void touchFile(String name)
            throws IOException

Set the modified time of an existing file to now.

Overview Package Class Use Tree Index Deprecated About
Prev Class \| Next Class	Frames \| No Frames
Summary: Nested \| Field \| Method \| Constr	Detail: Nested \| Field \| Method \| Constr