RegionGroupingProvider (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.wal.RegionGroupingProvider

All Implemented Interfaces:

WALProvider
```
@InterfaceAudience.Private
public class RegionGroupingProvider
extends Object
implements WALProvider
```
A WAL Provider that returns a WAL per group of regions. This provider follows the decorator pattern and mainly holds the logic for WAL grouping. WAL creation/roll/close is delegated to DELEGATE_PROVIDER Region grouping is handled via RegionGroupingProvider.RegionGroupingStrategy and can be configured via the property "hbase.wal.regiongrouping.strategy". Current strategy choices are
- defaultStrategy : Whatever strategy this version of HBase picks. currently "bounded".
- identity : each region belongs to its own group.
- bounded : bounded number of groups and region evenly assigned to each group.
Optionally, a FQCN to a custom implementation may be given.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static interface RegionGroupingProvider.RegionGroupingStrategy
Map identifiers to a group number.
- Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.wal.WALProvider
  WALProvider.Writer

Nested Classes
Modifier and Type	Class and Description
`static interface`	`RegionGroupingProvider.RegionGroupingStrategy` Map identifiers to a group number.

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`DEFAULT_DELEGATE_PROVIDER`
`static String`	`DEFAULT_REGION_GROUPING_STRATEGY`
`static String`	`DELEGATE_PROVIDER` delegate provider for WAL creation/roll/close
`static String`	`REGION_GROUPING_STRATEGY`

Constructor Summary

Constructors
Constructor and Description

RegionGroupingProvider()

Constructors
Constructor and Description
`RegionGroupingProvider()`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` shutdown utstanding WALs and clean up any persisted state.
`long`	`getLogFileSize()` Get size of the log files this provider is managing
`long`	`getNumLogFiles()` Get number of the log files this provider is managing
`WAL`	`getWAL(byte[] identifier, byte[] namespace)`
`List<WAL>`	`getWALs()`
`void`	`init(WALFactory factory, org.apache.hadoop.conf.Configuration conf, List<WALActionsListener> listeners, String providerId)` Set up the provider to create wals.
`void`	`shutdown()` persist outstanding WALs to storage and stop accepting new appends.

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

- Field Detail
  - REGION_GROUPING_STRATEGY
```
public static final String REGION_GROUPING_STRATEGY
```
    See Also:
    Constant Field Values
  - DEFAULT_REGION_GROUPING_STRATEGY
```
public static final String DEFAULT_REGION_GROUPING_STRATEGY
```
  - DELEGATE_PROVIDER
```
public static final String DELEGATE_PROVIDER
```
    delegate provider for WAL creation/roll/close
    
    See Also:
    Constant Field Values
  - DEFAULT_DELEGATE_PROVIDER
```
public static final String DEFAULT_DELEGATE_PROVIDER
```
- Constructor Detail
  - RegionGroupingProvider
```
public RegionGroupingProvider()
```
- Method Detail
  - init
```
public void init(WALFactory factory,
        org.apache.hadoop.conf.Configuration conf,
        List<WALActionsListener> listeners,
        String providerId)
          throws IOException
```
    Description copied from interface: WALProvider
    
    Set up the provider to create wals. will only be called once per instance.
    
    Specified by:
    
    init in interface WALProvider
    
    Parameters:
    factory - factory that made us may not be null
    conf - may not be null
    listeners - may be null
    providerId - differentiate between providers from one factory. may be null
    
    Throws:
    
    IOException
  - getWALs
```
public List<WAL> getWALs()
                  throws IOException
```
    Specified by:
    
    getWALs in interface WALProvider
    
    Returns:
    the List of WALs that are used by this server
    
    Throws:
    
    IOException
  - getWAL
```
public WAL getWAL(byte[] identifier,
         byte[] namespace)
           throws IOException
```
    Specified by:
    
    getWAL in interface WALProvider
    
    Parameters:
    identifier - may not be null. contents will not be altered.
    namespace - could be null, and will use default namespace if null
    
    Returns:
    a WAL for writing entries for the given region.
    
    Throws:
    
    IOException
  - shutdown
```
public void shutdown()
              throws IOException
```
    Description copied from interface: WALProvider
    
    persist outstanding WALs to storage and stop accepting new appends. This method serves as shorthand for sending a sync to every WAL provided by a given implementation. Those WALs will also stop accepting new writes.
    
    Specified by:
    
    shutdown in interface WALProvider
    
    Throws:
    
    IOException
  - close
```
public void close()
           throws IOException
```
    Description copied from interface: WALProvider
    
    shutdown utstanding WALs and clean up any persisted state. Call this method only when you will not need to replay any of the edits to the WALs from this provider. After this call completes, the underlying resources should have been reclaimed.
    
    Specified by:
    
    close in interface WALProvider
    
    Throws:
    
    IOException
  - getNumLogFiles
```
public long getNumLogFiles()
```
    Description copied from interface: WALProvider
    
    Get number of the log files this provider is managing
    
    Specified by:
    
    getNumLogFiles in interface WALProvider
  - getLogFileSize
```
public long getLogFileSize()
```
    Description copied from interface: WALProvider
    
    Get size of the log files this provider is managing
    
    Specified by:
    
    getLogFileSize in interface WALProvider

Class RegionGroupingProvider

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.wal.WALProvider

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

REGION_GROUPING_STRATEGY

DEFAULT_REGION_GROUPING_STRATEGY

DELEGATE_PROVIDER

DEFAULT_DELEGATE_PROVIDER

Constructor Detail

RegionGroupingProvider

Method Detail

init

getWALs

getWAL

shutdown

close

getNumLogFiles

getLogFileSize