Block (Apache Hadoop HDFS Client 3.4.1.100-eep-941 API)

java.lang.Object
- org.apache.hadoop.hdfs.protocol.Block

All Implemented Interfaces:

java.lang.Comparable<Block>, org.apache.hadoop.io.Writable
```
@Private
@Evolving
public class Block
extends java.lang.Object
implements org.apache.hadoop.io.Writable, java.lang.Comparable<Block>
```
A Block is a Hadoop FS primitive, identified by its block ID (a long). A block also has an accompanying generation stamp. A generation stamp is a monotonically increasing 8-byte number for each block that is maintained persistently by the NameNode. However, for the purposes of this class, two Blocks are considered equal iff they have the same block ID.

See Also:

equals(Object), hashCode(), compareTo(Block)

Field Summary

Fields
Modifier and Type	Field	Description
`static java.lang.String`	`BLOCK_FILE_PREFIX`
`static java.util.regex.Pattern`	`blockFilePattern`
`static java.lang.String`	`METADATA_EXTENSION`
`static java.util.regex.Pattern`	`metaFilePattern`
`static java.util.regex.Pattern`	`metaOrBlockFilePattern`

Constructor Summary

Constructors
Constructor	Description
`Block()`
`Block(long blkid)`
`Block(long blkid, long len, long generationStamp)`
`Block(java.io.File f, long len, long genstamp)`	Find the blockid from the given filename
`Block(Block blk)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`appendStringTo(java.lang.StringBuilder sb)`
`int`	`compareTo(Block b)`	Compares this Block with the specified Block for order.
`boolean`	`equals(java.lang.Object obj)`	Indicates whether some Block is "equal to" this one.
`static long`	`filename2id(java.lang.String name)`
`long`	`getBlockId()`
`static long`	`getBlockId(java.lang.String metaOrBlockFile)`	Get the blockId from the name of the meta or block file
`java.lang.String`	`getBlockName()`	Get the block name.
`long`	`getGenerationStamp()`
`static long`	`getGenerationStamp(java.lang.String metaFile)`	Get generation stamp from the name of the metafile name
`long`	`getNumBytes()`
`int`	`hashCode()`	Returns a hash code value for the Block.
`static boolean`	`isBlockFilename(java.io.File f)`
`static boolean`	`isMetaFilename(java.lang.String name)`
`static boolean`	`matchingIdAndGenStamp(Block a, Block b)`	A helper function to determine if two blocks are equal, based on the block ID and the generation stamp.
`static java.io.File`	`metaToBlockFile(java.io.File metaFile)`
`void`	`readFields(java.io.DataInput in)`
`void`	`readId(java.io.DataInput in)`
`void`	`set(long blkid, long len, long genStamp)`
`void`	`setBlockId(long bid)`
`void`	`setGenerationStamp(long stamp)`
`void`	`setNumBytes(long len)`
`java.lang.String`	`toString()`	Get the block name.
`static java.lang.String`	`toString(Block b)`	A helper method to output the string representation of the Block portion of a derived class' instance.
`void`	`write(java.io.DataOutput out)`
`void`	`writeId(java.io.DataOutput out)`

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

- Field Detail
  - BLOCK_FILE_PREFIX
```
public static final java.lang.String BLOCK_FILE_PREFIX
```
    See Also:
    
    Constant Field Values
  - METADATA_EXTENSION
```
public static final java.lang.String METADATA_EXTENSION
```
    See Also:
    
    Constant Field Values
  - blockFilePattern
```
public static final java.util.regex.Pattern blockFilePattern
```
  - metaFilePattern
```
public static final java.util.regex.Pattern metaFilePattern
```
  - metaOrBlockFilePattern
```
public static final java.util.regex.Pattern metaOrBlockFilePattern
```
- Constructor Detail
  - Block
```
public Block()
```
  - Block
```
public Block(long blkid,
             long len,
             long generationStamp)
```
  - Block
```
public Block(long blkid)
```
  - Block
```
public Block(Block blk)
```
  - Block
```
public Block(java.io.File f,
             long len,
             long genstamp)
```
    Find the blockid from the given filename
- Method Detail
  - isBlockFilename
```
public static boolean isBlockFilename(java.io.File f)
```
  - filename2id
```
public static long filename2id(java.lang.String name)
```
  - isMetaFilename
```
public static boolean isMetaFilename(java.lang.String name)
```
  - metaToBlockFile
```
public static java.io.File metaToBlockFile(java.io.File metaFile)
```
  - getGenerationStamp
```
public static long getGenerationStamp(java.lang.String metaFile)
```
    Get generation stamp from the name of the metafile name
  - getBlockId
```
public static long getBlockId(java.lang.String metaOrBlockFile)
```
    Get the blockId from the name of the meta or block file
  - set
```
public void set(long blkid,
                long len,
                long genStamp)
```
  - getBlockId
```
public long getBlockId()
```
  - setBlockId
```
public void setBlockId(long bid)
```
  - getBlockName
```
public java.lang.String getBlockName()
```
    Get the block name. The format of the name is in the format:
    blk_1, blk_2, blk_3, etc.
    
    Returns:
    
    the block name
  - getNumBytes
```
public long getNumBytes()
```
  - setNumBytes
```
public void setNumBytes(long len)
```
  - getGenerationStamp
```
public long getGenerationStamp()
```
  - setGenerationStamp
```
public void setGenerationStamp(long stamp)
```
  - toString
```
public static java.lang.String toString(Block b)
```
    A helper method to output the string representation of the Block portion of a derived class' instance.
    
    Parameters:
    
    b - the target object
    
    Returns:
    
    the string representation of the block
  - toString
```
public java.lang.String toString()
```
    Get the block name. The format of the name is in the format:
    blk_block-id_generation, blk_1_1, blk_1_2, blk_2_1, etc.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the full block name
  - appendStringTo
```
public void appendStringTo(java.lang.StringBuilder sb)
```
  - write
```
public void write(java.io.DataOutput out)
           throws java.io.IOException
```
    Specified by:
    
    write in interface org.apache.hadoop.io.Writable
    
    Throws:
    
    java.io.IOException
  - readFields
```
public void readFields(java.io.DataInput in)
                throws java.io.IOException
```
    Specified by:
    
    readFields in interface org.apache.hadoop.io.Writable
    
    Throws:
    
    java.io.IOException
  - writeId
```
public void writeId(java.io.DataOutput out)
             throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - readId
```
public void readId(java.io.DataInput in)
            throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - compareTo
```
public int compareTo(@Nonnull
                     Block b)
```
    Compares this Block with the specified Block for order. Returns a negative integer, zero, or a positive integer as this Block is less than, equal to, or greater than the specified Block. Blocks are ordered based on their block ID.
    
    Specified by:
    
    compareTo in interface java.lang.Comparable<Block>
    
    Parameters:
    
    b - the Block to be compared
    
    Returns:
    
    a negative integer, zero, or a positive integer as this Block is less than, equal to, or greater than the specified Block.
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Indicates whether some Block is "equal to" this one. Two blocks are considered equal if they have the same block ID.
    
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    obj - the reference object with which to compare.
    
    Returns:
    
    true if this Block is the same as the argument; false otherwise.
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for the Block. The hash code adheres to the general contract of hashCode. If two Blocks are equal according to the equals(Object) method, then calling the hashCode method on each of the two blocks produce the same integer result.
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    a hash code value for this block
    
    See Also:
    
    equals(Object)
  - matchingIdAndGenStamp
```
public static boolean matchingIdAndGenStamp(Block a,
                                            Block b)
```
    A helper function to determine if two blocks are equal, based on the block ID and the generation stamp. This is a different equalities check than the default behavior of the Block class. Two blocks are considered equal by this function iff the two blocks have the same block ID and the same generation stamp, or if both blocks are null.
    
    Parameters:
    
    a - an object
    
    b - an object to be compared with a for equality
    
    Returns:
    
    true if the blocks are deeply equal to each other and false otherwise
    
    See Also:
    
    Block

Class Block

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

BLOCK_FILE_PREFIX

METADATA_EXTENSION

blockFilePattern

metaFilePattern

metaOrBlockFilePattern

Constructor Detail

Block

Block

Block

Block

Block

Method Detail

isBlockFilename

filename2id

isMetaFilename

metaToBlockFile

getGenerationStamp

getBlockId

set

getBlockId

setBlockId

getBlockName

getNumBytes

setNumBytes

getGenerationStamp

setGenerationStamp

toString

toString

appendStringTo

write

readFields

writeId

readId

compareTo

equals

hashCode

matchingIdAndGenStamp