HFileBlock.AbstractFSReader (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.io.hfile.HFileBlock.AbstractFSReader

All Implemented Interfaces:

HFileBlock.FSReader

Direct Known Subclasses:

HFileBlock.FSReaderImpl

Enclosing class:

HFileBlock
```
private abstract static class HFileBlock.AbstractFSReader
extends Object
implements HFileBlock.FSReader
```
A common implementation of some methods of HFileBlock.FSReader and some tools for implementing HFile format version-specific block readers.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`DEFAULT_BUFFER_SIZE` The default buffer size for our buffered streams
`protected HFileContext`	`fileContext`
`protected long`	`fileSize` The size of the file we are reading from, or -1 if unknown.
`protected int`	`hdrSize` The size of the header
`protected HFileSystem`	`hfs` The filesystem used to access data
`protected org.apache.hadoop.fs.Path`	`path` The path (if any) where this data is coming from
`protected Lock`	`streamLock`

Constructor Summary

Constructors
Constructor and Description
`HFileBlock.AbstractFSReader(long fileSize, HFileSystem hfs, org.apache.hadoop.fs.Path path, HFileContext fileContext)`

Method Summary

Methods
Modifier and Type	Method and Description
`HFileBlock.BlockIterator`	`blockRange(long startOffset, long endOffset)` Creates a block iterator over the given portion of the `HFile`.
`protected int`	`readAtOffset(org.apache.hadoop.fs.FSDataInputStream istream, byte[] dest, int destOffset, int size, boolean peekIntoNextBlock, long fileOffset, boolean pread)` Does a positional read or a seek and read into the given buffer.

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

Methods inherited from interface org.apache.hadoop.hbase.io.hfile.HFileBlock.FSReader
closeStreams, getBlockDecodingContext, getDefaultBlockDecodingContext, readBlockData, unbufferStream

- Field Detail
  - fileSize
```
protected long fileSize
```
    The size of the file we are reading from, or -1 if unknown.
  - hdrSize
```
protected final int hdrSize
```
    The size of the header
  - hfs
```
protected HFileSystem hfs
```
    The filesystem used to access data
  - path
```
protected org.apache.hadoop.fs.Path path
```
    The path (if any) where this data is coming from
  - streamLock
```
protected final Lock streamLock
```
  - DEFAULT_BUFFER_SIZE
```
public static final int DEFAULT_BUFFER_SIZE
```
    The default buffer size for our buffered streams
    
    See Also:
    Constant Field Values
  - fileContext
```
protected HFileContext fileContext
```
- Constructor Detail
  - HFileBlock.AbstractFSReader
```
public HFileBlock.AbstractFSReader(long fileSize,
                           HFileSystem hfs,
                           org.apache.hadoop.fs.Path path,
                           HFileContext fileContext)
                            throws IOException
```
    Throws:
    
    IOException
- Method Detail
  - blockRange
```
public HFileBlock.BlockIterator blockRange(long startOffset,
                                  long endOffset)
```
    Description copied from interface: HFileBlock.FSReader
    
    Creates a block iterator over the given portion of the HFile. The iterator returns blocks starting with offset such that offset <= startOffset < endOffset. Returned blocks are always unpacked.
    
    Specified by:
    
    blockRange in interface HFileBlock.FSReader
    
    Parameters:
    startOffset - the offset of the block to start iteration with
    endOffset - the offset to end iteration at (exclusive)
    
    Returns:
    an iterator of blocks between the two given offsets
  - readAtOffset
```
protected int readAtOffset(org.apache.hadoop.fs.FSDataInputStream istream,
               byte[] dest,
               int destOffset,
               int size,
               boolean peekIntoNextBlock,
               long fileOffset,
               boolean pread)
                    throws IOException
```
    Does a positional read or a seek and read into the given buffer. Returns the on-disk size of the next block, or -1 if it could not be determined.
    
    Parameters:
    dest - destination buffer
    destOffset - offset in the destination buffer
    size - size of the block to be read
    peekIntoNextBlock - whether to read the next block's on-disk size
    fileOffset - position in the stream to read at
    pread - whether we should do a positional read
    istream - The input source of data
    
    Returns:
    the on-disk size of the next block with header size included, or -1 if it could not be determined
    
    Throws:
    
    IOException

Class HFileBlock.AbstractFSReader

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.hadoop.hbase.io.hfile.HFileBlock.FSReader

Field Detail

fileSize

hdrSize

hfs

path

streamLock

DEFAULT_BUFFER_SIZE

fileContext

Constructor Detail

HFileBlock.AbstractFSReader

Method Detail

blockRange

readAtOffset