com.h3c.util.persistence.cassandra.query

Class CountQuery<F,C>

java.lang.Object

com.h3c.util.persistence.cassandra.query.CountQuery<F,C>

Type Parameters:

F - Type of filter object.

C - Type of the context of the query. This varies with the implementation of the application and the database used.

All Implemented Interfaces:

ReadQuery<Long,C>

public class CountQuery<F,C>
extends Object
implements ReadQuery<Long,C>

Query for count number of entries with in a table or column family which matches the filter definition.

Constructor Summary

Constructors

Constructor and Description
CountQuery(F filter, Dao<?,?,?,F,?,C> dao) Creates a Count query.

Method Summary

Methods

Modifier and Type	Method and Description
Long	execute(C context) Execute the count query.

Methods inherited from class java.lang.Object

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

Constructor Detail

CountQuery

public CountQuery(F filter,
          Dao<?,?,?,F,?,C> dao)

Creates a Count query.

Parameters:

filter - filter to apply.

dao - the DAO to carry out the operation.

Method Detail

execute

public Long execute(C context)
             throws Exception

Execute the count query.

Specified by:

execute in interface ReadQuery<Long,C>

Parameters:

context - Context of the query.

Returns:

Return the number of entries matches the filter criteria.

Throws:

NullPointerException - In case of context is null.

Exception - Throws Exception in case of any error in query execute.