Package org.apache.lucene.store

Class ByteBuffersDataOutput

java.lang.Object
org.apache.lucene.store.DataOutput
org.apache.lucene.store.ByteBuffersDataOutput
All Implemented Interfaces:
Accountable
public final class ByteBuffersDataOutput extends DataOutput implements Accountable
A DataOutput storing data in a list of ByteBuffers.

  • Field Details

    • ALLOCATE_BB_ON_HEAP

      public static final IntFunction<ByteBuffer> ALLOCATE_BB_ON_HEAP

    • NO_REUSE

      public static final Consumer<ByteBuffer> NO_REUSE
      A singleton instance of "no-reuse" buffer strategy.

    • DEFAULT_MIN_BITS_PER_BLOCK

      public static final int DEFAULT_MIN_BITS_PER_BLOCK
      Default minBitsPerBlock
      See Also:

    • DEFAULT_MAX_BITS_PER_BLOCK

      public static final int DEFAULT_MAX_BITS_PER_BLOCK
      Default maxBitsPerBlock
      See Also:

    • LIMIT_MIN_BITS_PER_BLOCK

      public static final int LIMIT_MIN_BITS_PER_BLOCK
      Smallest minBitsPerBlock allowed
      See Also:

    • LIMIT_MAX_BITS_PER_BLOCK

      public static final int LIMIT_MAX_BITS_PER_BLOCK
      Largest maxBitsPerBlock allowed
      See Also:

  • Constructor Details

    • ByteBuffersDataOutput

      public ByteBuffersDataOutput(long expectedSize)
      Create a new output, suitable for writing a file of around expectedSize bytes.

      Memory allocation will be optimized based on the expectedSize hint, so that there is less overhead for larger files.

      Parameters:
      expectedSize - estimated size of the output file

    • ByteBuffersDataOutput

      public ByteBuffersDataOutput()
      Creates a new output with all defaults.

    • ByteBuffersDataOutput

      public ByteBuffersDataOutput(int minBitsPerBlock, int maxBitsPerBlock, IntFunction<ByteBuffer> blockAllocate, Consumer<ByteBuffer> blockReuse)
      Expert: Creates a new output with custom parameters.
      Parameters:
      minBitsPerBlock - minimum bits per block
      maxBitsPerBlock - maximum bits per block
      blockAllocate - block allocator
      blockReuse - block recycler

  • Method Details

    • writeByte

      public void writeByte(byte b)
      Description copied from class: DataOutput
      Writes a single byte.

      The most primitive data type is an eight-bit byte. Files are accessed as sequences of bytes. All other data types are defined as sequences of bytes, so file formats are byte-order independent.

      Specified by:
      writeByte in class DataOutput
      See Also:

    • writeBytes

      public void writeBytes(byte[] src, int offset, int length)
      Description copied from class: DataOutput
      Writes an array of bytes.
      Specified by:
      writeBytes in class DataOutput
      Parameters:
      src - the bytes to write
      offset - the offset in the byte array
      length - the number of bytes to write
      See Also:

    • writeBytes

      public void writeBytes(byte[] b, int length)
      Description copied from class: DataOutput
      Writes an array of bytes.
      Overrides:
      writeBytes in class DataOutput
      Parameters:
      b - the bytes to write
      length - the number of bytes to write
      See Also:

    • writeBytes

      public void writeBytes(byte[] b)

    • writeBytes

      public void writeBytes(ByteBuffer buffer)

    • toBufferList

      public ArrayList<ByteBuffer> toBufferList()
      Return a list of read-only view of ByteBuffer blocks over the current content written to the output.

    • toWriteableBufferList

      public ArrayList<ByteBuffer> toWriteableBufferList()
      Returns a list of writeable blocks over the (source) content buffers.

      This method returns the raw content of source buffers that may change over the lifetime of this object (blocks can be recycled or discarded, for example). Most applications should favor calling toBufferList() which returns a read-only view over the content of the source buffers.

      The difference between toBufferList() and toWriteableBufferList() is that read-only view of source buffers will always return false from ByteBuffer.hasArray() (which sometimes may be required to avoid double copying).

    • toDataInput

      public ByteBuffersDataInput toDataInput()
      Return a ByteBuffersDataInput for the set of current buffers (toBufferList()).

    • toArrayCopy

      public byte[] toArrayCopy()
      Return a contiguous array with the current content written to the output. The returned array is always a copy (can be mutated).

      If the size() of the underlying buffers exceeds maximum size of Java array, an RuntimeException will be thrown.

    • copyTo

      public void copyTo(DataOutput output) throws IOException
      Copy the current content of this object into another DataOutput.
      Throws:
      IOException

    • size

      public long size()
      Returns:
      The number of bytes written to this output so far.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • writeShort

      public void writeShort(short v)
      Description copied from class: DataOutput
      Writes a short as two bytes (LE byte order).
      Overrides:
      writeShort in class DataOutput
      See Also:

    • writeInt

      public void writeInt(int v)
      Description copied from class: DataOutput
      Writes an int as four bytes (LE byte order).
      Overrides:
      writeInt in class DataOutput
      See Also:

    • writeLong

      public void writeLong(long v)
      Description copied from class: DataOutput
      Writes a long as eight bytes (LE byte order).
      Overrides:
      writeLong in class DataOutput
      See Also:

    • writeString

      public void writeString(String v)
      Description copied from class: DataOutput
      Writes a string.

      Writes strings as UTF-8 encoded bytes. First the length, in bytes, is written as a VInt, followed by the bytes.

      Overrides:
      writeString in class DataOutput
      See Also:

    • writeMapOfStrings

      public void writeMapOfStrings(Map<String,String> map)
      Description copied from class: DataOutput
      Writes a String map.

      First the size is written as an vInt, followed by each key-value pair written as two consecutive Strings.

      Overrides:
      writeMapOfStrings in class DataOutput
      Parameters:
      map - Input map.

    • writeSetOfStrings

      public void writeSetOfStrings(Set<String> set)
      Description copied from class: DataOutput
      Writes a String set.

      First the size is written as an vInt, followed by each value written as a String.

      Overrides:
      writeSetOfStrings in class DataOutput
      Parameters:
      set - Input set.

    • ramBytesUsed

      public long ramBytesUsed()
      Description copied from interface: Accountable
      Return the memory usage of this object in bytes. Negative values are illegal.
      Specified by:
      ramBytesUsed in interface Accountable

    • reset

      public void reset()
      This method resets this object to a clean (zero-size) state and publishes any currently allocated buffers for reuse to the reuse strategy provided in the constructor.

      Sharing byte buffers for reads and writes is dangerous and will very likely lead to hard-to-debug issues, use with great care.

    • newResettableInstance

      public static ByteBuffersDataOutput newResettableInstance()
      Returns:
      Returns a new ByteBuffersDataOutput with the reset() capability.