me.jaksa.hbase.lite

Class Table<T>

java.lang.Object

me.jaksa.hbase.lite.Table<T>

public class Table<T>
extends Object

Represents an HBase table for a specific type of domain object. You can have multiple Tables defined for the same table in HBase each having a different set of columns and a different domain object. In that case storing an object in one table will not overwrite columns that are not defined for that table.

Author:

Jaksa Vuckovic

Constructor Summary

Constructors

Constructor and Description
Table(Class<T> clazz)
Table(org.apache.hadoop.hbase.client.HTable hTable, String columns, Converter<T> converter)
Table(String name, String columns, Converter<T> converter)

Method Summary

Modifier and Type	Method and Description
void	delete(Object key) Deletes the object with the specified key.
void	deleteAll()
T	get(Object key) Retrieve the object with the specified key.
<I> Mapped<I>	map(SerializableFunction<T,I> f) Transform the data using the given function.
<P> Partitioned<P,T>	partitionBy(PartitionFunction<T,P> f) Partition the data according to a partitioning function.
void	put(T t) Store the object into HBase.
<R extends Serializable> R	reduce(SerializableFunction<Iterable<T>,R> f) Applies a function over all the data.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Table

public Table(Class<T> clazz)

Table

public Table(String name,
             String columns,
             Converter<T> converter)

Parameters:

name - the name of the table

columns - a comma separated list of columns (e.g. "fam1:col1,fam1:col2,fam2:col1")

converter - the converter for the domain objects

Table

public Table(org.apache.hadoop.hbase.client.HTable hTable,
             String columns,
             Converter<T> converter)

Method Detail

get

public T get(Object key)
      throws IOException

Retrieve the object with the specified key. This method will transform the key to a byte array before invoking HBase.

Parameters:

key - the key of this object

Returns:

the object requested

Throws:

IOException - if there is a communication problem with HBase

put

public void put(T t)
         throws IOException

Store the object into HBase.

Parameters:

t - the object to store

Throws:

IOException - if there is a communication problem with HBase

delete

public void delete(Object key)
            throws IOException

Deletes the object with the specified key. This method will transform the key to a byte array before invoking HBase.

Parameters:

key - the key of the object to delete

Throws:

IOException - if there is a communication problem with HBase

partitionBy

public <P> Partitioned<P,T> partitionBy(PartitionFunction<T,P> f)
                                 throws IOException

Partition the data according to a partitioning function. The function should return the partition id. All data for which the function produces the same key will end up in the same parititon.

Type Parameters:

P - type of partition id

Parameters:

f - the function that determines the partition

Returns:

data that can be processed further

Throws:

IOException - if there is a communication problem with HBase

map

public <I> Mapped<I> map(SerializableFunction<T,I> f)
                  throws IOException

Transform the data using the given function.

Type Parameters:

I - the type of the output data

Parameters:

f - the function to transform the data

Returns:

the data resulting from applying the function

Throws:

IOException - if there is a communication problem with HBase

reduce

public <R extends Serializable> R reduce(SerializableFunction<Iterable<T>,R> f)
                                  throws IOException

Applies a function over all the data. The function receives an Iterable for the data in the table and should produce a result.

Type Parameters:

R - the type of the result

Parameters:

f - the function to be applied.

Returns:

the result of the function

Throws:

IOException - if there is a communication problem with HBase

deleteAll

public void deleteAll()
               throws IOException

Throws:

IOException