MetaScanner (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.client.MetaScanner

```
@InterfaceAudience.Private
public class MetaScanner
extends Object
```
Scanner class that contains the hbase:meta table scanning logic. Provided visitors will be called for each row. Although public visibility, this is not a public-facing API and may evolve in minor releases.
Note that during concurrent region splits, the scanner might not see hbase:meta changes across rows (for parent and daughter entries) consistently. see HBASE-5986, and MetaScanner.DefaultMetaScannerVisitor for details.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`MetaScanner.DefaultMetaScannerVisitor` A MetaScannerVisitor that skips offline regions and split parents
`static interface`	`MetaScanner.MetaScannerVisitor` Visitor class called to process each row of the hbase:meta table
`static class`	`MetaScanner.MetaScannerVisitorBase`
`static class`	`MetaScanner.TableMetaScannerVisitor` A MetaScannerVisitor for a table.

Field Summary

Fields
Modifier and Type Field and Description

private static org.apache.commons.logging.Log LOG

Fields
Modifier and Type	Field and Description
`private static org.apache.commons.logging.Log`	`LOG`

Constructor Summary

Constructors
Constructor and Description

MetaScanner()

Constructors
Constructor and Description
`MetaScanner()`

Method Summary

Methods
Modifier and Type	Method and Description
`static NavigableMap<HRegionInfo,ServerName>`	`allTableRegions(org.apache.hadoop.conf.Configuration conf, Connection connection, TableName tableName, boolean offlined)` Deprecated. Use `allTableRegions(Connection, TableName)` instead
`static NavigableMap<HRegionInfo,ServerName>`	`allTableRegions(Connection connection, TableName tableName)` Lists all of the table regions currently in META.
`private static Result`	`getClosestRowOrBefore(Table metaTable, TableName userTableName, byte[] row, boolean useMetaReplicas)`
`static HRegionInfo`	`getHRegionInfo(Result data)` Deprecated. Use `MetaTableAccessor.getRegionLocations(Result)`
`static List<HRegionInfo>`	`listAllRegions(org.apache.hadoop.conf.Configuration conf, Connection connection, boolean offlined)` Lists all of the regions currently in META.
`static List<RegionLocations>`	`listTableRegionLocations(org.apache.hadoop.conf.Configuration conf, Connection connection, TableName tableName)` Lists table regions and locations grouped by region range from META.
`static void`	`metaScan(Connection connection, MetaScanner.MetaScannerVisitor visitor)` Scans the meta table and calls a visitor on each RowResult and uses a empty start row value as table name.
`static void`	`metaScan(Connection connection, MetaScanner.MetaScannerVisitor visitor, TableName userTableName)` Scans the meta table and calls a visitor on each RowResult.
`static void`	`metaScan(Connection connection, MetaScanner.MetaScannerVisitor visitor, TableName userTableName, byte[] row, int rowLimit)` Scans the meta table and calls a visitor on each RowResult.
`(package private) static void`	`metaScan(Connection connection, MetaScanner.MetaScannerVisitor visitor, TableName tableName, byte[] row, int rowLimit, TableName metaTableName)` Scans the meta table and calls a visitor on each RowResult.

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

- Field Detail
  - LOG
```
private static final org.apache.commons.logging.Log LOG
```
- Constructor Detail
  - MetaScanner
```
public MetaScanner()
```
- Method Detail
  - metaScan
```
public static void metaScan(Connection connection,
            MetaScanner.MetaScannerVisitor visitor)
                     throws IOException
```
    Scans the meta table and calls a visitor on each RowResult and uses a empty start row value as table name.
    Visible for testing. Use metaScan(Connection, MetaScannerVisitor, TableName) instead.
    
    Parameters:
    visitor - A custom visitor
    
    Throws:
    
    IOException - e
  - metaScan
```
public static void metaScan(Connection connection,
            MetaScanner.MetaScannerVisitor visitor,
            TableName userTableName)
                     throws IOException
```
    Scans the meta table and calls a visitor on each RowResult. Uses a table name to locate meta regions.
    
    Parameters:
    connection - connection to use internally (null to use a new instance)
    visitor - visitor object
    userTableName - User table name in meta table to start scan at. Pass null if not interested in a particular table.
    
    Throws:
    
    IOException - e
  - metaScan
```
public static void metaScan(Connection connection,
            MetaScanner.MetaScannerVisitor visitor,
            TableName userTableName,
            byte[] row,
            int rowLimit)
                     throws IOException
```
    Scans the meta table and calls a visitor on each RowResult. Uses a table name and a row name to locate meta regions. And it only scans at most rowLimit of rows.
    Visible for testing. Use metaScan(Connection, MetaScannerVisitor, TableName) instead.
    
    Parameters:
    connection - to scan on
    visitor - Visitor object.
    userTableName - User table name in meta table to start scan at. Pass null if not interested in a particular table.
    row - Name of the row at the user table. The scan will start from the region row where the row resides.
    rowLimit - Max of processed rows. If it is less than 0, it will be set to default value Integer.MAX_VALUE.
    
    Throws:
    
    IOException - e
  - metaScan
```
static void metaScan(Connection connection,
            MetaScanner.MetaScannerVisitor visitor,
            TableName tableName,
            byte[] row,
            int rowLimit,
            TableName metaTableName)
              throws IOException
```
    Scans the meta table and calls a visitor on each RowResult. Uses a table name and a row name to locate meta regions. And it only scans at most rowLimit of rows.
    
    Parameters:
    connection - connection to use internally (null to use a new instance)
    visitor - Visitor object. Closes the visitor before returning.
    tableName - User table name in meta table to start scan at. Pass null if not interested in a particular table.
    row - Name of the row at the user table. The scan will start from the region row where the row resides.
    rowLimit - Max of processed rows. If it is less than 0, it will be set to default value Integer.MAX_VALUE.
    metaTableName - Meta table to scan, root or meta.
    
    Throws:
    
    IOException - e
  - getClosestRowOrBefore
```
private static Result getClosestRowOrBefore(Table metaTable,
                           TableName userTableName,
                           byte[] row,
                           boolean useMetaReplicas)
                                     throws IOException
```
    Returns:
    Get closest metatable region row to passed row
    
    Throws:
    
    IOException
  - getHRegionInfo
```
@Deprecated
public static HRegionInfo getHRegionInfo(Result data)
```
    Deprecated. Use MetaTableAccessor.getRegionLocations(Result)
    
    Returns HRegionInfo object from the column HConstants.CATALOG_FAMILY:HConstants.REGIONINFO_QUALIFIER of the catalog table Result.
    
    Parameters:
    data - a Result object from the catalog table scan
    
    Returns:
    HRegionInfo or null
  - listAllRegions
```
public static List<HRegionInfo> listAllRegions(org.apache.hadoop.conf.Configuration conf,
                               Connection connection,
                               boolean offlined)
                                        throws IOException
```
    Lists all of the regions currently in META.
    
    Parameters:
    conf - configuration
    connection - to connect with
    offlined - True if we are to include offlined regions, false and we'll leave out offlined regions from returned list.
    
    Returns:
    List of all user-space regions.
    
    Throws:
    
    IOException
  - allTableRegions
```
@Deprecated
public static NavigableMap<HRegionInfo,ServerName> allTableRegions(org.apache.hadoop.conf.Configuration conf,
                                                              Connection connection,
                                                              TableName tableName,
                                                              boolean offlined)
                                                            throws IOException
```
    Deprecated. Use allTableRegions(Connection, TableName) instead
    
    Lists all of the table regions currently in META.
    
    Parameters:
    conf -
    offlined - True if we are to include offlined regions, false and we'll leave out offlined regions from returned list.
    
    Returns:
    Map of all user-space regions to servers
    
    Throws:
    
    IOException
  - allTableRegions
```
public static NavigableMap<HRegionInfo,ServerName> allTableRegions(Connection connection,
                                                   TableName tableName)
                                                            throws IOException
```
    Lists all of the table regions currently in META.
    
    Parameters:
    connection -
    tableName -
    
    Returns:
    Map of all user-space regions to servers
    
    Throws:
    
    IOException
  - listTableRegionLocations
```
public static List<RegionLocations> listTableRegionLocations(org.apache.hadoop.conf.Configuration conf,
                                             Connection connection,
                                             TableName tableName)
                                                      throws IOException
```
    Lists table regions and locations grouped by region range from META.
    
    Throws:
    
    IOException

Class MetaScanner

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG

Constructor Detail

MetaScanner

Method Detail

metaScan

metaScan

metaScan

metaScan

getClosestRowOrBefore

getHRegionInfo

listAllRegions

allTableRegions

allTableRegions

listTableRegionLocations