Get (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.client.Operation
- - org.apache.hadoop.hbase.client.OperationWithAttributes
  - - org.apache.hadoop.hbase.client.Query
    - - org.apache.hadoop.hbase.client.Get

All Implemented Interfaces:

Comparable<Row>, Attributes, Row
```
@InterfaceAudience.Public
@InterfaceStability.Stable
public class Get
extends Query
implements Row, Comparable<Row>
```
Used to perform Get operations on a single row.
To get everything for a row, instantiate a Get object with the row to get. To further narrow the scope of what to Get, use the methods below.
To get all columns from specific families, execute addFamily for each family to retrieve.
To get specific columns, execute addColumn for each column to retrieve.
To only retrieve columns within a specific range of version timestamps, execute setTimeRange.
To only retrieve columns with a specific timestamp, execute setTimestamp.
To limit the number of versions of each column to be returned, execute setMaxVersions.
To add a filter, call setFilter.

Field Summary
- Fields inherited from class org.apache.hadoop.hbase.client.Query
  colFamTimeRangeMap, consistency, filter, loadColumnFamiliesOnDemand, targetReplicaId
- Fields inherited from class org.apache.hadoop.hbase.client.OperationWithAttributes
  ID_ATRIBUTE

Constructor Summary

Constructors
Constructor and Description

Get(byte[] row)
Create a Get operation for the specified row.

Get(Get get)
Copy-constructor

Constructors
Constructor and Description
`Get(byte[] row)` Create a Get operation for the specified row.
`Get(Get get)` Copy-constructor

Method Summary

Methods
Modifier and Type	Method and Description
`Get`	`addColumn(byte[] family, byte[] qualifier)` Get the column from the specific family with the specified qualifier.
`Get`	`addFamily(byte[] family)` Get all columns from the specified family.
`int`	`compareTo(Row other)`
`boolean`	`equals(Object obj)`
`Set<byte[]>`	`familySet()` Method for retrieving the keys in the familyMap
`boolean`	`getCacheBlocks()` Get whether blocks should be cached for this Get.
`Map<byte[],NavigableSet<byte[]>>`	`getFamilyMap()` Method for retrieving the get's familyMap
`Map<String,Object>`	`getFingerprint()` Compile the table and column family (i.e.
`int`	`getMaxResultsPerColumnFamily()` Method for retrieving the get's maximum number of values to return per Column Family
`int`	`getMaxVersions()` Method for retrieving the get's maximum number of version
`byte[]`	`getRow()` Method for retrieving the get's row
`int`	`getRowOffsetPerColumnFamily()` Method for retrieving the get's offset per row per column family (#kvs to be skipped)
`TimeRange`	`getTimeRange()` Method for retrieving the get's TimeRange
`boolean`	`hasFamilies()` Method for checking if any families have been inserted into this Get
`int`	`hashCode()`
`boolean`	`isCheckExistenceOnly()`
`boolean`	`isClosestRowBefore()`
`int`	`numFamilies()` Method for retrieving the number of families to get from
`Get`	`setACL(Map<String,org.apache.hadoop.hbase.security.access.Permission> perms)`
`Get`	`setACL(String user, org.apache.hadoop.hbase.security.access.Permission perms)`
`Get`	`setAttribute(String name, byte[] value)` Sets an attribute.
`Get`	`setAuthorizations(org.apache.hadoop.hbase.security.visibility.Authorizations authorizations)` Sets the authorizations to be used by this Query
`Get`	`setCacheBlocks(boolean cacheBlocks)` Set whether blocks should be cached for this Get.
`Get`	`setCheckExistenceOnly(boolean checkExistenceOnly)`
`Get`	`setClosestRowBefore(boolean closestRowBefore)`
`Get`	`setColumnFamilyTimeRange(byte[] cf, long minStamp, long maxStamp)` Get versions of columns only within the specified timestamp range, [minStamp, maxStamp) on a per CF bases.
`Get`	`setConsistency(Consistency consistency)` Sets the consistency level for this operation
`Get`	`setFilter(Filter filter)` Apply the specified server-side filter when performing the Query.
`Get`	`setId(String id)` This method allows you to set an identifier on an operation.
`Get`	`setIsolationLevel(IsolationLevel level)` Set the isolation level for this query.
`Get`	`setLoadColumnFamiliesOnDemand(boolean value)` Set the value indicating whether loading CFs on demand should be allowed (cluster default is false).
`Get`	`setMaxResultsPerColumnFamily(int limit)` Set the maximum number of values to return per row per Column Family
`Get`	`setMaxVersions()` Get all available versions.
`Get`	`setMaxVersions(int maxVersions)` Get up to the specified number of versions of each column.
`Get`	`setReplicaId(int Id)` Specify region replica id where Query will fetch data from.
`Get`	`setRowOffsetPerColumnFamily(int offset)` Set offset for the row per Column Family.
`Get`	`setTimeRange(long minStamp, long maxStamp)` Get versions of columns only within the specified timestamp range, [minStamp, maxStamp).
`Get`	`setTimeStamp(long timestamp)` Get versions of columns with the specified timestamp.
`Map<String,Object>`	`toMap(int maxCols)` Compile the details beyond the scope of getFingerprint (row, columns, timestamps, etc.) into a Map along with the fingerprinted information.

Methods inherited from class org.apache.hadoop.hbase.client.Query
doLoadColumnFamiliesOnDemand, getACL, getAuthorizations, getColumnFamilyTimeRange, getConsistency, getFilter, getIsolationLevel, getLoadColumnFamiliesOnDemandValue, getReplicaId

Methods inherited from class org.apache.hadoop.hbase.client.OperationWithAttributes
getAttribute, getAttributeSize, getAttributesMap, getId

Methods inherited from class org.apache.hadoop.hbase.client.Operation
toJSON, toJSON, toMap, toString, toString

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

- Constructor Detail
  - Get
```
public Get(byte[] row)
```
    Create a Get operation for the specified row.
    If no further operations are done, this will get the latest version of all columns in all families of the specified row.
    
    Parameters:
    row - row key
  - Get
```
public Get(Get get)
```
    Copy-constructor
    
    Parameters:
    get -
- Method Detail
  - isCheckExistenceOnly
```
public boolean isCheckExistenceOnly()
```
  - setCheckExistenceOnly
```
public Get setCheckExistenceOnly(boolean checkExistenceOnly)
```
  - isClosestRowBefore
```
public boolean isClosestRowBefore()
```
  - setClosestRowBefore
```
public Get setClosestRowBefore(boolean closestRowBefore)
```
  - addFamily
```
public Get addFamily(byte[] family)
```
    Get all columns from the specified family.
    Overrides previous calls to addColumn for this family.
    
    Parameters:
    family - family name
    
    Returns:
    the Get object
  - addColumn
```
public Get addColumn(byte[] family,
            byte[] qualifier)
```
    Get the column from the specific family with the specified qualifier.
    Overrides previous calls to addFamily for this family.
    
    Parameters:
    family - family name
    qualifier - column qualifier
    
    Returns:
    the Get objec
  - setTimeRange
```
public Get setTimeRange(long minStamp,
               long maxStamp)
                 throws IOException
```
    Get versions of columns only within the specified timestamp range, [minStamp, maxStamp).
    
    Parameters:
    minStamp - minimum timestamp value, inclusive
    maxStamp - maximum timestamp value, exclusive
    
    Returns:
    this for invocation chaining
    
    Throws:
    
    IOException
  - setTimeStamp
```
public Get setTimeStamp(long timestamp)
                 throws IOException
```
    Get versions of columns with the specified timestamp.
    
    Parameters:
    timestamp - version timestamp
    
    Returns:
    this for invocation chaining
    
    Throws:
    
    IOException
  - setColumnFamilyTimeRange
```
public Get setColumnFamilyTimeRange(byte[] cf,
                           long minStamp,
                           long maxStamp)
```
    Description copied from class: Query
    
    Get versions of columns only within the specified timestamp range, [minStamp, maxStamp) on a per CF bases. Note, default maximum versions to return is 1. If your time range spans more than one version and you want all versions returned, up the number of versions beyond the default. Column Family time ranges take precedence over the global time range.
    
    Overrides:
    
    setColumnFamilyTimeRange in class Query
    
    Parameters:
    cf - the column family for which you want to restrict
    minStamp - minimum timestamp value, inclusive
    maxStamp - maximum timestamp value, exclusive
    
    Returns:
    this
  - setMaxVersions
```
public Get setMaxVersions()
```
    Get all available versions.
    
    Returns:
    this for invocation chaining
  - setMaxVersions
```
public Get setMaxVersions(int maxVersions)
                   throws IOException
```
    Get up to the specified number of versions of each column.
    
    Parameters:
    maxVersions - maximum versions for each column
    
    Returns:
    this for invocation chaining
    
    Throws:
    
    IOException - if invalid number of versions
  - setLoadColumnFamiliesOnDemand
```
public Get setLoadColumnFamiliesOnDemand(boolean value)
```
    Description copied from class: Query
    
    Set the value indicating whether loading CFs on demand should be allowed (cluster default is false). On-demand CF loading doesn't load column families until necessary, e.g. if you filter on one column, the other column family data will be loaded only for the rows that are included in result, not all rows like in normal case. With column-specific filters, like SingleColumnValueFilter w/filterIfMissing == true, this can deliver huge perf gains when there's a cf with lots of data; however, it can also lead to some inconsistent results, as follows: - if someone does a concurrent update to both column families in question you may get a row that never existed, e.g. for { rowKey = 5, { cat_videos => 1 }, { video => "my cat" } } someone puts rowKey 5 with { cat_videos => 0 }, { video => "my dog" }, concurrent scan filtering on "cat_videos == 1" can get { rowKey = 5, { cat_videos => 1 }, { video => "my dog" } }. - if there's a concurrent split and you have more than 2 column families, some rows may be missing some column families.
    
    Overrides:
    
    setLoadColumnFamiliesOnDemand in class Query
  - setMaxResultsPerColumnFamily
```
public Get setMaxResultsPerColumnFamily(int limit)
```
    Set the maximum number of values to return per row per Column Family
    
    Parameters:
    limit - the maximum number of values returned / row / CF
    
    Returns:
    this for invocation chaining
  - setRowOffsetPerColumnFamily
```
public Get setRowOffsetPerColumnFamily(int offset)
```
    Set offset for the row per Column Family. This offset is only within a particular row/CF combination. It gets reset back to zero when we move to the next row or CF.
    
    Parameters:
    offset - is the number of kvs that will be skipped.
    
    Returns:
    this for invocation chaining
  - setFilter
```
public Get setFilter(Filter filter)
```
    Description copied from class: Query
    
    Apply the specified server-side filter when performing the Query. Only Filter.filterKeyValue(Cell) is called AFTER all tests for ttl, column match, deletes and max versions have been run.
    
    Overrides:
    
    setFilter in class Query
    
    Parameters:
    filter - filter to run on the server
    
    Returns:
    this for invocation chaining
  - setCacheBlocks
```
public Get setCacheBlocks(boolean cacheBlocks)
```
    Set whether blocks should be cached for this Get.
    This is true by default. When true, default settings of the table and family are used (this will never override caching blocks if the block cache is disabled for that family or entirely).
    
    Parameters:
    cacheBlocks - if false, default settings are overridden and blocks will not be cached
  - getCacheBlocks
```
public boolean getCacheBlocks()
```
    Get whether blocks should be cached for this Get.
    
    Returns:
    true if default caching should be used, false if blocks should not be cached
  - getRow
```
public byte[] getRow()
```
    Method for retrieving the get's row
    
    Specified by:
    
    getRow in interface Row
    
    Returns:
    row
  - getMaxVersions
```
public int getMaxVersions()
```
    Method for retrieving the get's maximum number of version
    
    Returns:
    the maximum number of version to fetch for this get
  - getMaxResultsPerColumnFamily
```
public int getMaxResultsPerColumnFamily()
```
    Method for retrieving the get's maximum number of values to return per Column Family
    
    Returns:
    the maximum number of values to fetch per CF
  - getRowOffsetPerColumnFamily
```
public int getRowOffsetPerColumnFamily()
```
    Method for retrieving the get's offset per row per column family (#kvs to be skipped)
    
    Returns:
    the row offset
  - getTimeRange
```
public TimeRange getTimeRange()
```
    Method for retrieving the get's TimeRange
    
    Returns:
    timeRange
  - familySet
```
public Set<byte[]> familySet()
```
    Method for retrieving the keys in the familyMap
    
    Returns:
    keys in the current familyMap
  - numFamilies
```
public int numFamilies()
```
    Method for retrieving the number of families to get from
    
    Returns:
    number of families
  - hasFamilies
```
public boolean hasFamilies()
```
    Method for checking if any families have been inserted into this Get
    
    Returns:
    true if familyMap is non empty false otherwise
  - getFamilyMap
```
public Map<byte[],NavigableSet<byte[]>> getFamilyMap()
```
    Method for retrieving the get's familyMap
    
    Returns:
    familyMap
  - getFingerprint
```
public Map<String,Object> getFingerprint()
```
    Compile the table and column family (i.e. schema) information into a String. Useful for parsing and aggregation by debugging, logging, and administration tools.
    
    Specified by:
    
    getFingerprint in class Operation
    
    Returns:
    Map
  - toMap
```
public Map<String,Object> toMap(int maxCols)
```
    Compile the details beyond the scope of getFingerprint (row, columns, timestamps, etc.) into a Map along with the fingerprinted information. Useful for debugging, logging, and administration tools.
    
    Specified by:
    
    toMap in class Operation
    
    Parameters:
    maxCols - a limit on the number of columns output prior to truncation
    
    Returns:
    Map
  - compareTo
```
public int compareTo(Row other)
```
    Specified by:
    
    compareTo in interface Comparable<Row>
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - setAttribute
```
public Get setAttribute(String name,
               byte[] value)
```
    Description copied from interface: Attributes
    
    Sets an attribute. In case value = null attribute is removed from the attributes map. Attribute names starting with _ indicate system attributes.
    
    Specified by:
    
    setAttribute in interface Attributes
    
    Overrides:
    
    setAttribute in class OperationWithAttributes
    
    Parameters:
    name - attribute name
    value - attribute value
  - setId
```
public Get setId(String id)
```
    Description copied from class: OperationWithAttributes
    
    This method allows you to set an identifier on an operation. The original motivation for this was to allow the identifier to be used in slow query logging, but this could obviously be useful in other places. One use of this could be to put a class.method identifier in here to see where the slow query is coming from.
    
    Overrides:
    
    setId in class OperationWithAttributes
    
    Parameters:
    id - id to set for the scan
  - setAuthorizations
```
public Get setAuthorizations(org.apache.hadoop.hbase.security.visibility.Authorizations authorizations)
```
    Description copied from class: Query
    
    Sets the authorizations to be used by this Query
    
    Overrides:
    
    setAuthorizations in class Query
  - setACL
```
public Get setACL(Map<String,org.apache.hadoop.hbase.security.access.Permission> perms)
```
    Overrides:
    
    setACL in class Query
    
    Parameters:
    perms - A map of permissions for a user or users
  - setACL
```
public Get setACL(String user,
         org.apache.hadoop.hbase.security.access.Permission perms)
```
    Overrides:
    
    setACL in class Query
    
    Parameters:
    user - User short name
    perms - Permissions for the user
  - setConsistency
```
public Get setConsistency(Consistency consistency)
```
    Description copied from class: Query
    
    Sets the consistency level for this operation
    
    Overrides:
    
    setConsistency in class Query
    
    Parameters:
    consistency - the consistency level
  - setReplicaId
```
public Get setReplicaId(int Id)
```
    Description copied from class: Query
    
    Specify region replica id where Query will fetch data from. Use this together with Query.setConsistency(Consistency) passing Consistency.TIMELINE to read data from a specific replicaId.
    Expert: This is an advanced API exposed. Only use it if you know what you are doing
    
    Overrides:
    
    setReplicaId in class Query
  - setIsolationLevel
```
public Get setIsolationLevel(IsolationLevel level)
```
    Description copied from class: Query
    
    Set the isolation level for this query. If the isolation level is set to READ_UNCOMMITTED, then this query will return data from committed and uncommitted transactions. If the isolation level is set to READ_COMMITTED, then this query will return data from committed transactions only. If a isolation level is not explicitly set on a Query, then it is assumed to be READ_COMMITTED.
    
    Overrides:
    
    setIsolationLevel in class Query
    
    Parameters:
    level - IsolationLevel for this query

Class Get

Field Summary

Fields inherited from class org.apache.hadoop.hbase.client.Query

Fields inherited from class org.apache.hadoop.hbase.client.OperationWithAttributes

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.client.Query

Methods inherited from class org.apache.hadoop.hbase.client.OperationWithAttributes

Methods inherited from class org.apache.hadoop.hbase.client.Operation

Methods inherited from class java.lang.Object

Constructor Detail

Get

Get

Method Detail

isCheckExistenceOnly

setCheckExistenceOnly

isClosestRowBefore

setClosestRowBefore

addFamily

addColumn

setTimeRange

setTimeStamp

setColumnFamilyTimeRange

setMaxVersions

setMaxVersions

setLoadColumnFamiliesOnDemand

setMaxResultsPerColumnFamily

setRowOffsetPerColumnFamily

setFilter

setCacheBlocks

getCacheBlocks

getRow

getMaxVersions

getMaxResultsPerColumnFamily

getRowOffsetPerColumnFamily

getTimeRange

familySet

numFamilies

hasFamilies

getFamilyMap

getFingerprint

toMap

compareTo

hashCode

equals

setAttribute

setId

setAuthorizations

setACL

setACL

setConsistency

setReplicaId

setIsolationLevel