CompoundDirectory (Lucene 10.5.0 core API)
Description: declaration: package: org.apache.lucene.codecs, class: CompoundDirectory

Package org.apache.lucene.codecs

# Class CompoundDirectory

java.lang.Object
org.apache.lucene.store.Directory
org.apache.lucene.codecs.CompoundDirectory

All Implemented Interfaces:
  `Closeable`, `AutoCloseable`

public abstract class CompoundDirectory extends Directory
A read-only `Directory` that consists of a view over a compound file.

See Also:
  - `CompoundFormat`
WARNING: This API is experimental and might change in incompatible ways in the next release.

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `CompoundDirectory()`
  Sole constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `abstract void`
  `checkIntegrity()`
  Checks consistency of this directory.
  `final IndexOutput`
  `createOutput(String name, IOContext context)`
  Creates a new, empty file in the directory and returns an `IndexOutput` instance for appending data to this file.
  `final IndexOutput`
  `createTempOutput(String prefix, String suffix, IOContext context)`
  Creates a new, empty, temporary file in the directory and returns an `IndexOutput` instance for appending data to this file.
  `final void`
  `deleteFile(String name)`
  Not implemented
  `final Lock`
  `obtainLock(String name)`
  Acquires and returns a `Lock` for a file with the given name.
  `final void`
  `rename(String from, String to)`
  Not implemented
  `final void`
  `sync(Collection<String> names)`
  Ensures that any writes to these files are moved to stable storage (made durable).
  `final void`
  `syncMetaData()`
  Ensures that directory metadata, such as recent file renames, are moved to stable storage.

  ### Methods inherited from class org.apache.lucene.store.Directory

  `close, copyFrom, ensureOpen, fileLength, getPendingDeletions, getTempFileName, listAll, openChecksumInput, openInput, toString`

  ### Methods inherited from class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- ## Constructor Details

  - ### CompoundDirectory

    protected CompoundDirectory()
    Sole constructor.

- ## Method Details

  - ### checkIntegrity

    public abstract void checkIntegrity() throws IOException
    Checks consistency of this directory.

    Note that this may be costly in terms of I/O, e.g. may involve computing a checksum value against large data files.

    Throws:
      `IOException`

  - ### deleteFile

    public final void deleteFile(String name)
    Not implemented
    Specified by:
      `deleteFile` in class `Directory`
    Parameters:
      `name` - the name of an existing file.
    Throws:
      `UnsupportedOperationException` - always: not supported by CFS

  - ### rename

    public final void rename(String from, String to)
    Not implemented
    Specified by:
      `rename` in class `Directory`
    Throws:
      `UnsupportedOperationException` - always: not supported by CFS

  - ### syncMetaData

    public final void syncMetaData()
    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`
    See Also:
      - `Directory.sync(Collection)`

  - ### createOutput

    public final IndexOutput createOutput(String name, IOContext context) throws IOException
    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 final IndexOutput createTempOutput(String prefix, String suffix, IOContext context) throws IOException
    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`

  - ### sync

    public final void sync(Collection<String> names)
    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`
    See Also:
      - `Directory.syncMetaData()`

  - ### obtainLock

    public final Lock obtainLock(String name)
    Description copied from class: `Directory`
    Acquires and returns a `Lock` for a file with the given name.
    Specified by:
      `obtainLock` in class `Directory`
    Parameters:
      `name` - the name of the lock file