Package org.apache.lucene.store

Class ByteBuffersDirectory

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    public final class ByteBuffersDirectory
extends BaseDirectory
    A ByteBuffer-based Directory implementation that can be used to store index files on the heap.

    Important: Note that MMapDirectory is nearly always a better choice as it uses OS caches more effectively (through memory-mapped buffers). A heap-based directory like this one can have the advantage in case of ephemeral, small, short-lived indexes when disk syncs provide an additional overhead.

    • Field Detail

      • OUTPUT_AS_MANY_BUFFERS

        public static final java.util.function.BiFunction<java.lang.String,​ByteBuffersDataOutput,​IndexInput> OUTPUT_AS_MANY_BUFFERS

      • OUTPUT_AS_MANY_BUFFERS_LUCENE

        public static final java.util.function.BiFunction<java.lang.String,​ByteBuffersDataOutput,​IndexInput> OUTPUT_AS_MANY_BUFFERS_LUCENE

      • tempFileName

        private final java.util.function.Function<java.lang.String,​java.lang.String> tempFileName

      • outputToInput

        private final java.util.function.BiFunction<java.lang.String,​ByteBuffersDataOutput,​IndexInput> outputToInput
        Conversion between a buffered index output and the corresponding index input for a given file.

    • Constructor Detail

      • ByteBuffersDirectory

        public ByteBuffersDirectory()

      • ByteBuffersDirectory

        public ByteBuffersDirectory​(LockFactory lockFactory)

    • Method Detail

      • listAll

        public java.lang.String[] listAll()
                           throws java.io.IOException
        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
        Throws:
        java.io.IOException - in case of I/O error

      • deleteFile

        public void deleteFile​(java.lang.String name)
                throws java.io.IOException
        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

      • fileLength

        public long fileLength​(java.lang.String name)
                throws java.io.IOException
        Description copied from class: Directory
        Returns the byte length of a file in the directory. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.
        Specified by:
        fileLength 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
        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
        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

      • rename

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

      • sync

        public void sync​(java.util.Collection<java.lang.String> names)
          throws java.io.IOException
        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()

      • syncMetaData

        public void syncMetaData()
                  throws java.io.IOException
        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
        Description copied from class: Directory
        Opens a stream for reading an existing file. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-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()
           throws java.io.IOException
        Description copied from class: Directory
        Closes the directory.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in class Directory
        Throws:
        java.io.IOException

      • getPendingDeletions

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