Reference (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.io.Reference

```
@InterfaceAudience.Private
public class Reference
extends Object
```
A reference to the top or bottom half of a store file where 'bottom' is the first half of the file containing the keys that sort lowest and 'top' is the second half of the file with keys that sort greater than those of the bottom half. The file referenced lives under a different region. References are made at region split time.
References work with a special half store file type. References know how to write out the reference format in the file system and are what is juggled when references are mixed in with direct store files. The half store file type is used reading the referred to file.
References to store files located over in some other region look like this in the file system 1278437856009925445.3323223323: i.e. an id followed by hash of the referenced region. Note, a region is itself not splittable if it has instances of store file references. References are cleaned up by compactions.

Constructor Summary

Constructors
Constructor and Description

Reference()
Deprecated.
need by pb serialization

Constructors
Constructor and Description
`Reference()` Deprecated. need by pb serialization

Method Summary

Methods
Modifier and Type	Method and Description
`org.apache.hadoop.hbase.protobuf.generated.FSProtos.Reference`	`convert()`
`static Reference`	`convert(org.apache.hadoop.hbase.protobuf.generated.FSProtos.Reference r)`
`static Reference`	`createBottomReference(byte[] splitRow)`
`static Reference`	`createTopReference(byte[] splitRow)`
`boolean`	`equals(Object o)`
`org.apache.hadoop.hbase.io.Reference.Range`	`getFileRegion()`
`byte[]`	`getSplitKey()`
`int`	`hashCode()`
`static boolean`	`isTopFileRegion(org.apache.hadoop.hbase.io.Reference.Range r)`
`static Reference`	`read(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path p)` Read a Reference from FileSystem.
`void`	`readFields(DataInput in)` Deprecated. Writables are going away. Use the pb serialization methods instead. Remove in a release after 0.96 goes out. This is here only to migrate old Reference files written with Writables before 0.96.
`String`	`toString()`
`org.apache.hadoop.fs.Path`	`write(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path p)`

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

Constructor Detail
- Reference
```
@Deprecated
public Reference()
```
  Deprecated. need by pb serialization
  
  Used by serializations.

Method Detail

createTopReference
```
public static Reference createTopReference(byte[] splitRow)
```
Parameters:
splitRow -

Returns:
A Reference that points at top half of a an hfile

createBottomReference
```
public static Reference createBottomReference(byte[] splitRow)
```
Parameters:
splitRow -

Returns:
A Reference that points at the bottom half of a an hfile

getFileRegion

public org.apache.hadoop.hbase.io.Reference.Range getFileRegion()

Returns:: Range

getSplitKey
```
public byte[] getSplitKey()
```
Returns:
splitKey

toString
```
public String toString()
```
Overrides:

toString in class Object

See Also:
Object.toString()

isTopFileRegion

public static boolean isTopFileRegion(org.apache.hadoop.hbase.io.Reference.Range r)

readFields
```
@Deprecated
public void readFields(DataInput in)
                throws IOException
```
Deprecated. Writables are going away. Use the pb serialization methods instead. Remove in a release after 0.96 goes out. This is here only to migrate old Reference files written with Writables before 0.96.

Throws:

IOException

write

public org.apache.hadoop.fs.Path write(org.apache.hadoop.fs.FileSystem fs,
                              org.apache.hadoop.fs.Path p)
                                throws IOException

Throws:: IOException

read

public static Reference read(org.apache.hadoop.fs.FileSystem fs,
             org.apache.hadoop.fs.Path p)
                      throws IOException

Read a Reference from FileSystem.

Parameters:: fs -; p -
Returns:: New Reference made from passed p
Throws:: IOException

convert

public org.apache.hadoop.hbase.protobuf.generated.FSProtos.Reference convert()

convert

public static Reference convert(org.apache.hadoop.hbase.protobuf.generated.FSProtos.Reference r)

hashCode
```
public int hashCode()
```
Overrides:

hashCode in class Object

equals
```
public boolean equals(Object o)
```
Overrides:

equals in class Object

Class Reference

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Reference

Method Detail

createTopReference

createBottomReference

getFileRegion

getSplitKey

toString

isTopFileRegion

readFields

write

read

convert

convert

hashCode

equals