org.apache.lucene.store
Class RAMDirectory

java.lang.Object
  extended by org.apache.lucene.store.Directory
      extended by org.apache.lucene.store.RAMDirectory
All Implemented Interfaces:
Closeable, Serializable

public class RAMDirectory
extends Directory
implements Serializable

A memory-resident Directory implementation. Locking implementation is by default the SingleInstanceLockFactory but can be changed with Directory.setLockFactory(org.apache.lucene.store.LockFactory).

See Also:
Serialized Form

Field Summary
protected  Map<String,RAMFile> fileMap
           
protected  AtomicLong sizeInBytes
           
 
Fields inherited from class org.apache.lucene.store.Directory
isOpen, lockFactory
 
Constructor Summary
RAMDirectory()
          Constructs an empty Directory.
RAMDirectory(Directory dir)
          Creates a new RAMDirectory instance from a different Directory implementation.
 
Method Summary
 void close()
          Closes the store to future operations, releasing associated memory.
 IndexOutput createOutput(String name)
          Creates a new, empty file in the directory with the given name.
 void deleteFile(String name)
          Removes an existing file in the directory.
 boolean fileExists(String name)
          Returns true iff the named file exists in this directory.
 long fileLength(String name)
          Returns the length in bytes of a file in the directory.
 long fileModified(String name)
          Returns the time the named file was last modified.
 String[] listAll()
          Returns an array of strings, one for each file in the directory.
protected  RAMFile newRAMFile()
          Returns a new RAMFile for storing data.
 IndexInput openInput(String name)
          Returns a stream reading an existing file.
 long sizeInBytes()
          Return total size in bytes of all files in this directory.
 void touchFile(String name)
          Deprecated. Lucene never uses this API; it will be removed in 4.0.
 
Methods inherited from class org.apache.lucene.store.Directory
clearLock, copy, copy, ensureOpen, getLockFactory, getLockID, makeLock, openInput, setLockFactory, sync, sync, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

fileMap

protected final Map<String,RAMFile> fileMap

sizeInBytes

protected final AtomicLong sizeInBytes
Constructor Detail

RAMDirectory

public RAMDirectory()
Constructs an empty Directory.


RAMDirectory

public RAMDirectory(Directory dir)
             throws IOException
Creates a new RAMDirectory instance from a different Directory implementation. This can be used to load a disk-based index into memory.

This should be used only with indices that can fit into memory.

Note that the resulting RAMDirectory instance is fully independent from the original Directory (it is a complete copy). Any subsequent changes to the original Directory will not be visible in the RAMDirectory instance.

Parameters:
dir - a Directory value
Throws:
IOException - if an error occurs
Method Detail

listAll

public final String[] listAll()
Description copied from class: Directory
Returns an array of strings, one for each file in the directory.

Specified by:
listAll in class Directory

fileExists

public final boolean fileExists(String name)
Returns true iff the named file exists in this directory.

Specified by:
fileExists in class Directory

fileModified

public final long fileModified(String name)
                        throws IOException
Returns the time the named file was last modified.

Specified by:
fileModified in class Directory
Throws:
IOException - if the file does not exist

touchFile

@Deprecated
public void touchFile(String name)
               throws IOException
Deprecated. Lucene never uses this API; it will be removed in 4.0.

Set the modified time of an existing file to now.

Specified by:
touchFile in class Directory
Throws:
IOException - if the file does not exist

fileLength

public final long fileLength(String name)
                      throws IOException
Returns the length in bytes of a file in the directory.

Specified by:
fileLength in class Directory
Parameters:
name - the name of the file for which to return the length.
Throws:
IOException - if the file does not exist

sizeInBytes

public final long sizeInBytes()
Return total size in bytes of all files in this directory. This is currently quantized to RAMOutputStream.BUFFER_SIZE.


deleteFile

public void deleteFile(String name)
                throws IOException
Removes an existing file in the directory.

Specified by:
deleteFile in class Directory
Throws:
IOException - if the file does not exist

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.

Specified by:
createOutput in class Directory
Throws:
IOException

newRAMFile

protected RAMFile newRAMFile()
Returns a new RAMFile for storing data. This method can be overridden to return different RAMFile impls, that e.g. override RAMFile.newBuffer(int).


openInput

public IndexInput openInput(String name)
                     throws IOException
Returns a stream reading an existing file.

Specified by:
openInput in class Directory
Throws:
IOException

close

public void close()
Closes the store to future operations, releasing associated memory.

Specified by:
close in interface Closeable
Specified by:
close in class Directory


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