Class RAMDirectory

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.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.

    • Constructor Detail

      • RAMDirectory

        public RAMDirectory()
        Deprecated.
        Constructs an empty Directory.
      • RAMDirectory

        public RAMDirectory​(FSDirectory dir,
                            IOContext context)
                     throws java.io.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:
        java.io.IOException - if an error occurs
      • RAMDirectory

        private RAMDirectory​(FSDirectory dir,
                             boolean closeDir,
                             IOContext context)
                      throws java.io.IOException
        Deprecated.
        Throws:
        java.io.IOException
    • Method Detail

      • listAll

        public final java.lang.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​(java.lang.String name)
        Deprecated.
      • fileLength

        public final long fileLength​(java.lang.String name)
                              throws java.io.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:
        java.io.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 java.util.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:
        Accountables
      • deleteFile

        public void deleteFile​(java.lang.String name)
                        throws java.io.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:
        java.io.IOException - in case of I/O error
      • createOutput

        public IndexOutput createOutput​(java.lang.String name,
                                        IOContext context)
                                 throws java.io.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:
        java.io.IOException - in case of I/O error
      • createTempOutput

        public IndexOutput createTempOutput​(java.lang.String prefix,
                                            java.lang.String suffix,
                                            IOContext context)
                                     throws java.io.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:
        java.io.IOException
      • sync

        public void sync​(java.util.Collection<java.lang.String> names)
                  throws java.io.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:
        java.io.IOException
        See Also:
        Directory.syncMetaData()
      • rename

        public void rename​(java.lang.String source,
                           java.lang.String dest)
                    throws java.io.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:
        java.io.IOException
      • syncMetaData

        public void syncMetaData()
                          throws java.io.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:
        java.io.IOException
        See Also:
        Directory.sync(Collection)
      • openInput

        public IndexInput openInput​(java.lang.String name,
                                    IOContext context)
                             throws java.io.IOException
        Deprecated.
        Returns a stream reading an existing file.
        Specified by:
        openInput in class Directory
        Parameters:
        name - the name of an existing file.
        Throws:
        java.io.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 java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in class Directory
      • getPendingDeletions

        public java.util.Set<java.lang.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