org.apache.lucene.codecs.uniformsplit

## Class BlockHeader

- java.lang.Object
- - org.apache.lucene.codecs.uniformsplit.BlockHeader

- All Implemented Interfaces:
    Accountable

      public class BlockHeader
      extends Object
      implements Accountable

  Block header containing block metadata.

  Holds the number of lines in the block.

  Holds the base file pointers to apply delta base encoding to all the file pointers in the block with `DeltaBaseTermStateSerializer`.

  Holds the offset to the details region of the block (the term states).

  Holds the offset to the middle term of the block to divide the number of terms to scan by 2.

  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `BlockHeader.Serializer` Reads/writes block header.

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected long` | `baseDocsFP`
    `protected long` | `basePayloadsFP`
    `protected long` | `basePositionsFP`
    `protected int` | `linesCount`
    `protected int` | `middleLineIndex`
    `protected int` | `middleLineOffset`
    `protected int` | `termStatesBaseOffset`

    - ### Fields inherited from interface org.apache.lucene.util.Accountable

      `NULL_ACCOUNTABLE`

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `BlockHeader()` Empty constructor.
    `protected` | `BlockHeader(int linesCount, long baseDocsFP, long basePositionsFP, long basePayloadsFP, int termStatesBaseOffset, int middleLineOffset)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `long` | `getBaseDocsFP()`
    `long` | `getBasePayloadsFP()`
    `long` | `getBasePositionsFP()`
    `int` | `getLinesCount()`
    `int` | `getMiddleLineIndex()`
    `int` | `getMiddleLineOffset()`
    `int` | `getTermStatesBaseOffset()`
    `long` | `ramBytesUsed()`
    `protected BlockHeader` | `reset(int linesCount, long baseDocsFP, long basePositionsFP, long basePayloadsFP, int termStatesBaseOffset, int middleTermOffset)`

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

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

    - ### Methods inherited from interface org.apache.lucene.util.Accountable

      `getChildResources`

- - ### Field Detail

    - #### linesCount

          protected int linesCount

    - #### baseDocsFP

          protected long baseDocsFP

    - #### basePositionsFP

          protected long basePositionsFP

    - #### basePayloadsFP

          protected long basePayloadsFP

    - #### termStatesBaseOffset

          protected int termStatesBaseOffset

    - #### middleLineIndex

          protected int middleLineIndex

    - #### middleLineOffset

          protected int middleLineOffset

  - ### Constructor Detail

    - #### BlockHeader

          protected BlockHeader(int linesCount,
                                long baseDocsFP,
                                long basePositionsFP,
                                long basePayloadsFP,
                                int termStatesBaseOffset,
                                int middleLineOffset)

      Parameters:
        `linesCount` - Number of lines in the block.
        `baseDocsFP` - File pointer to the docs of the first term with docs in the block.
        `basePositionsFP` - File pointer to the positions of the first term with positions in the block.
        `basePayloadsFP` - File pointer to the payloads of the first term with payloads in the block.
        `termStatesBaseOffset` - Offset to the details region of the block (the term states), relative to the block start.
        `middleLineOffset` - Offset to the middle term of the block, relative to the block start.

    - #### BlockHeader

          protected BlockHeader()

      Empty constructor. `reset(int, long, long, long, int, int)` must be called before writing.

  - ### Method Detail

    - #### reset

          protected BlockHeader reset(int linesCount,
                                      long baseDocsFP,
                                      long basePositionsFP,
                                      long basePayloadsFP,
                                      int termStatesBaseOffset,
                                      int middleTermOffset)

    - #### getLinesCount

          public int getLinesCount()

      Returns:
        The number of lines in the block.

    - #### getMiddleLineIndex

          public int getMiddleLineIndex()

      Returns:
        The index of the middle line of the block.

    - #### getMiddleLineOffset

          public int getMiddleLineOffset()

      Returns:
        The offset to the middle line of the block, relative to the block start.

    - #### getTermStatesBaseOffset

          public int getTermStatesBaseOffset()

      Returns:
        The offset to the details region of the block (the term states), relative to the block start.

    - #### getBaseDocsFP

          public long getBaseDocsFP()

      Returns:
        The file pointer to the docs of the first term with docs in the block.

    - #### getBasePositionsFP

          public long getBasePositionsFP()

      Returns:
        The file pointer to the positions of the first term with positions in the block.

    - #### getBasePayloadsFP

          public long getBasePayloadsFP()

      Returns:
        The file pointer to the payloads of the first term with payloads in the block.

    - #### ramBytesUsed

          public long ramBytesUsed()

      Specified by:
        `ramBytesUsed` in interface `Accountable`

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