Package org.apache.lucene.store

Class RAMDirectory

java.lang.Object
org.apache.lucene.store.Directory
org.apache.lucene.store.BaseDirectory
org.apache.lucene.store.RAMDirectory
All Implemented Interfaces:
Closeable, AutoCloseable, Accountable
@Deprecated public class RAMDirectory extends BaseDirectory implements Accountable
Deprecated.
This class uses inefficient synchronization and is discouraged in favor of MMapDirectory. It will be removed in future versions of Lucene.
A memory-resident Directory implementation. Locking implementation is by default the SingleInstanceLockFactory.

Warning: This class is not intended to work with huge indexes. Everything beyond several hundred megabytes will waste resources (GC cycles), because it uses an internal buffer size of 1024 bytes, producing millions of byte[1024] arrays. This class is optimized for small memory-resident indexes. It also has bad concurrency on multithreaded environments.

It is recommended to materialize large indexes on disk and use MMapDirectory, which is a high-performance directory implementation working directly on the file system cache of the operating system, so copying data to Java heap space is not useful.

  • Field Details

  • Constructor Details

    • RAMDirectory

      public RAMDirectory()
      Deprecated.
      Constructs an empty Directory.

    • RAMDirectory

      public RAMDirectory(LockFactory lockFactory)
      Deprecated.
      Constructs an empty Directory with the given LockFactory.

    • RAMDirectory

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

      Warning: This class is not intended to work with huge indexes. Everything beyond several hundred megabytes will waste resources (GC cycles), because it uses an internal buffer size of 1024 bytes, producing millions of byte[1024] arrays. This class is optimized for small memory-resident indexes. It also has bad concurrency on multithreaded environments.

      For disk-based indexes it is recommended to use MMapDirectory, which is a high-performance directory implementation working directly on the file system cache of the operating system, so copying data to Java heap space is not useful.

      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

    • RAMDirectory

      private RAMDirectory(FSDirectory dir, boolean closeDir, IOContext context) throws IOException
      Deprecated.
      Throws:
      IOException

  • Method Details

    • listAll

      public final String[] listAll()
      Deprecated.
      Description copied from class: Directory
      Returns names of all files stored in this directory. The output must be in sorted (UTF-16, java's String.compareTo(java.lang.String)) order.
      Specified by:
      listAll in class Directory

    • fileNameExists

      public final boolean fileNameExists(String name)
      Deprecated.

    • fileLength

      public final long fileLength(String name) throws IOException
      Deprecated.
      Returns the length in bytes of a file in the directory.
      Specified by:
      fileLength in class Directory
      Parameters:
      name - the name of an existing file.
      Throws:
      IOException - if the file does not exist

    • ramBytesUsed

      public final long ramBytesUsed()
      Deprecated.
      Return total size in bytes of all files in this directory. This is currently quantized to RAMOutputStream.BUFFER_SIZE.
      Specified by:
      ramBytesUsed in interface Accountable

    • getChildResources

      public Collection<Accountable> getChildResources()
      Deprecated.
      Description copied from interface: Accountable
      Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).
      Specified by:
      getChildResources in interface Accountable
      See Also:

    • deleteFile

      public void deleteFile(String name) throws IOException
      Deprecated.
      Description copied from class: Directory
      Removes an existing file in the directory. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.
      Specified by:
      deleteFile in class Directory
      Parameters:
      name - the name of an existing file.
      Throws:
      IOException - in case of I/O error

    • createOutput

      public IndexOutput createOutput(String name, IOContext context) throws IOException
      Deprecated.
      Description copied from class: Directory
      Creates a new, empty file in the directory and returns an IndexOutput instance for appending data to this file. This method must throw FileAlreadyExistsException if the file already exists.
      Specified by:
      createOutput in class Directory
      Parameters:
      name - the name of the file to create.
      Throws:
      IOException - in case of I/O error

    • createTempOutput

      public IndexOutput createTempOutput(String prefix, String suffix, IOContext context) throws IOException
      Deprecated.
      Description copied from class: Directory
      Creates a new, empty, temporary file in the directory and returns an IndexOutput instance for appending data to this file. The temporary file name (accessible via IndexOutput.getName()) will start with prefix, end with suffix and have a reserved file extension .tmp.
      Specified by:
      createTempOutput in class Directory
      Throws:
      IOException

    • newRAMFile

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

    • sync

      public void sync(Collection<String> names) throws IOException
      Deprecated.
      Description copied from class: Directory
      Ensures that any writes to these files are moved to stable storage (made durable). Lucene uses this to properly commit changes to the index, to prevent a machine/OS crash from corrupting the index.
      Specified by:
      sync in class Directory
      Throws:
      IOException
      See Also:

    • rename

      public void rename(String source, String dest) throws IOException
      Deprecated.
      Description copied from class: Directory
      Renames source file to dest file where dest must not already exist in the directory. It is permitted for this operation to not be truly atomic, for example both source and dest can be visible temporarily in Directory.listAll(). However, the implementation of this method must ensure the content of dest appears as the entire source atomically. So once dest is visible for readers, the entire content of previous source is visible. This method is used by IndexWriter to publish commits.
      Specified by:
      rename in class Directory
      Throws:
      IOException

    • syncMetaData

      public void syncMetaData() throws IOException
      Deprecated.
      Description copied from class: Directory
      Ensures that directory metadata, such as recent file renames, are moved to stable storage.
      Specified by:
      syncMetaData in class Directory
      Throws:
      IOException
      See Also:

    • openInput

      public IndexInput openInput(String name, IOContext context) throws IOException
      Deprecated.
      Returns a stream reading an existing file.
      Specified by:
      openInput in class Directory
      Parameters:
      name - the name of an existing file.
      Throws:
      IOException - in case of I/O error

    • close

      public void close()
      Deprecated.
      Closes the store to future operations, releasing associated memory.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in class Directory

    • getPendingDeletions

      public Set<String> getPendingDeletions()
      Deprecated.
      Description copied from class: Directory
      Returns a set of files currently pending deletion in this directory.
      Specified by:
      getPendingDeletions in class Directory