HFileBlockIndex.BlockIndexWriter (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.io.hfile.HFileBlockIndex.BlockIndexWriter

All Implemented Interfaces:

InlineBlockWriter

Enclosing class:

HFileBlockIndex
```
public static class HFileBlockIndex.BlockIndexWriter
extends Object
implements InlineBlockWriter
```
Writes the block index into the output stream. Generate the tree from bottom up. The leaf level is written to disk as a sequence of inline blocks, if it is larger than a certain number of bytes. If the leaf level is not large enough, we write all entries to the root level instead. After all leaf blocks have been written, we end up with an index referencing the resulting leaf index blocks. If that index is larger than the allowed root index size, the writer will break it up into reasonable-size intermediate-level index block chunks write those chunks out, and create another index referencing those chunks. This will be repeated until the remaining index is small enough to become the root index. However, in most practical cases we will only have leaf-level blocks and the root index, or just the root index.

Constructor Summary

Constructors
Constructor and Description
`HFileBlockIndex.BlockIndexWriter()` Creates a single-level block index writer
`HFileBlockIndex.BlockIndexWriter(HFileBlock.Writer blockWriter, CacheConfig cacheConf, String nameForCaching)` Creates a multi-level block index writer.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addEntry(byte[] firstKey, long blockOffset, int blockDataSize)` Add one index entry to the current leaf-level block.
`void`	`blockWritten(long offset, int onDiskSize, int uncompressedSize)` Called after an inline block has been written so that we can add an entry referring to that block to the parent-level index.
`void`	`ensureSingleLevel()`
`boolean`	`getCacheOnWrite()`
`BlockType`	`getInlineBlockType()` The type of blocks this block writer produces.
`int`	`getNumLevels()`
`int`	`getNumRootEntries()`
`long`	`getTotalUncompressedSize()` The total uncompressed size of the root index block, intermediate-level index blocks, and leaf-level index blocks.
`void`	`setMaxChunkSize(int maxChunkSize)`
`void`	`setMinIndexNumEntries(int minIndexNumEntries)`
`boolean`	`shouldWriteBlock(boolean closing)` Whether there is an inline block ready to be written.
`long`	`writeIndexBlocks(org.apache.hadoop.fs.FSDataOutputStream out)` Writes the root level and intermediate levels of the block index into the output stream, generating the tree from bottom up.
`void`	`writeInlineBlock(DataOutput out)` Write out the current inline index block.
`void`	`writeSingleLevelIndex(DataOutput out, String description)` Writes the block index data as a single level only.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - HFileBlockIndex.BlockIndexWriter
```
public HFileBlockIndex.BlockIndexWriter()
```
    Creates a single-level block index writer
  - HFileBlockIndex.BlockIndexWriter
```
public HFileBlockIndex.BlockIndexWriter(HFileBlock.Writer blockWriter,
                                CacheConfig cacheConf,
                                String nameForCaching)
```
    Creates a multi-level block index writer.
    
    Parameters:
    blockWriter - the block writer to use to write index blocks
    cacheConf - used to determine when and how a block should be cached-on-write.
- Method Detail
  - setMaxChunkSize
```
public void setMaxChunkSize(int maxChunkSize)
```
  - setMinIndexNumEntries
```
public void setMinIndexNumEntries(int minIndexNumEntries)
```
  - writeIndexBlocks
```
public long writeIndexBlocks(org.apache.hadoop.fs.FSDataOutputStream out)
                      throws IOException
```
    Writes the root level and intermediate levels of the block index into the output stream, generating the tree from bottom up. Assumes that the leaf level has been inline-written to the disk if there is enough data for more than one leaf block. We iterate by breaking the current level of the block index, starting with the index of all leaf-level blocks, into chunks small enough to be written to disk, and generate its parent level, until we end up with a level small enough to become the root level. If the leaf level is not large enough, there is no inline block index anymore, so we only write that level of block index to disk as the root level.
    
    Parameters:
    out - FSDataOutputStream
    
    Returns:
    position at which we entered the root-level index.
    
    Throws:
    
    IOException
  - writeSingleLevelIndex
```
public void writeSingleLevelIndex(DataOutput out,
                         String description)
                           throws IOException
```
    Writes the block index data as a single level only. Does not do any block framing.
    
    Parameters:
    out - the buffered output stream to write the index to. Typically a stream writing into an HFile block.
    description - a short description of the index being written. Used in a log message.
    
    Throws:
    
    IOException
  - getNumRootEntries
```
public final int getNumRootEntries()
```
    Returns:
    how many block index entries there are in the root level
  - getNumLevels
```
public int getNumLevels()
```
    Returns:
    the number of levels in this block index.
  - shouldWriteBlock
```
public boolean shouldWriteBlock(boolean closing)
```
    Whether there is an inline block ready to be written. In general, we write an leaf-level index block as an inline block as soon as its size as serialized in the non-root format reaches a certain threshold.
    
    Specified by:
    
    shouldWriteBlock in interface InlineBlockWriter
    
    Parameters:
    closing - whether the file is being closed, in which case we need to write out all available data and not wait to accumulate another block
  - writeInlineBlock
```
public void writeInlineBlock(DataOutput out)
                      throws IOException
```
    Write out the current inline index block. Inline blocks are non-root blocks, so the non-root index format is used.
    
    Specified by:
    
    writeInlineBlock in interface InlineBlockWriter
    
    Parameters:
    out -
    
    Throws:
    
    IOException
  - blockWritten
```
public void blockWritten(long offset,
                int onDiskSize,
                int uncompressedSize)
```
    Called after an inline block has been written so that we can add an entry referring to that block to the parent-level index.
    
    Specified by:
    
    blockWritten in interface InlineBlockWriter
    
    Parameters:
    offset - the offset of the block in the stream
    onDiskSize - the on-disk size of the block
    uncompressedSize - the uncompressed size of the block
  - getInlineBlockType
```
public BlockType getInlineBlockType()
```
    Description copied from interface: InlineBlockWriter
    
    The type of blocks this block writer produces.
    
    Specified by:
    
    getInlineBlockType in interface InlineBlockWriter
  - addEntry
```
public void addEntry(byte[] firstKey,
            long blockOffset,
            int blockDataSize)
```
    Add one index entry to the current leaf-level block. When the leaf-level block gets large enough, it will be flushed to disk as an inline block.
    
    Parameters:
    firstKey - the first key of the data block
    blockOffset - the offset of the data block
    blockDataSize - the on-disk size of the data block (HFile format version 2), or the uncompressed size of the data block ( HFile format version 1).
  - ensureSingleLevel
```
public void ensureSingleLevel()
                       throws IOException
```
    Throws:
    
    IOException - if we happened to write a multi-level index.
  - getCacheOnWrite
```
public boolean getCacheOnWrite()
```
    Specified by:
    
    getCacheOnWrite in interface InlineBlockWriter
    
    Returns:
    true if we are using cache-on-write. This is configured by the caller of the constructor by either passing a valid block cache or null.
  - getTotalUncompressedSize
```
public long getTotalUncompressedSize()
```
    The total uncompressed size of the root index block, intermediate-level index blocks, and leaf-level index blocks.
    
    Returns:
    the total uncompressed size of all index blocks

Class HFileBlockIndex.BlockIndexWriter

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

HFileBlockIndex.BlockIndexWriter

HFileBlockIndex.BlockIndexWriter

Method Detail

setMaxChunkSize

setMinIndexNumEntries

writeIndexBlocks

writeSingleLevelIndex

getNumRootEntries

getNumLevels

shouldWriteBlock

writeInlineBlock

blockWritten

getInlineBlockType

addEntry

ensureSingleLevel

getCacheOnWrite

getTotalUncompressedSize