com.datastax.driver.core

Class AggregateMetadata

java.lang.Object

com.datastax.driver.core.AggregateMetadata

public class AggregateMetadata
extends Object

Describes a CQL aggregate function (created with CREATE AGGREGATE...).

Method Summary

Modifier and Type	Method and Description
String	asCQLQuery() Returns a CQL query representing this function.
boolean	equals(Object other)
String	exportAsString() Returns a CQL query representing this function in human readable form.
List<DataType>	getArgumentTypes() Returns the types of this aggregate's arguments.
FunctionMetadata	getFinalFunc() Returns the final function of this aggregate.
Object	getInitCond() Returns the initial state value of this aggregate.
KeyspaceMetadata	getKeyspace() Returns the keyspace this aggregate belongs to.
DataType	getReturnType() Returns the return type of this aggregate.
String	getSignature() Returns the CQL signature of this aggregate.
String	getSimpleName() Returns the simple name of this aggregate.
FunctionMetadata	getStateFunc() Returns the state function of this aggregate.
DataType	getStateType() Returns the state type of this aggregate.
int	hashCode()
boolean	isDeterministic()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

exportAsString

public String exportAsString()

Returns a CQL query representing this function in human readable form.

This method is equivalent to asCQLQuery() but the output is formatted.

Returns:

the CQL query representing this function.

asCQLQuery

public String asCQLQuery()

Returns a CQL query representing this function.

This method returns a single 'CREATE FUNCTION' query corresponding to this function definition.

Returns:

the 'CREATE FUNCTION' query corresponding to this function.

toString

public String toString()

Overrides:

toString in class Object

getKeyspace

public KeyspaceMetadata getKeyspace()

Returns the keyspace this aggregate belongs to.

Returns:

the keyspace metadata of the keyspace this aggregate belongs to.

getSignature

public String getSignature()

Returns the CQL signature of this aggregate.

This is the name of the aggregate, followed by the names of the argument types between parentheses, like it was specified in the CREATE AGGREGATE... statement, for example sum(int).

Note that the returned signature is not qualified with the keyspace name.

Returns:

the signature of this aggregate.

getSimpleName

public String getSimpleName()

Returns the simple name of this aggregate.

This is the name of the aggregate, without arguments. Note that aggregates can be overloaded with different argument lists, therefore the simple name may not be unique. For example, sum(int) and sum(int,int) both have the simple name sum.

Returns:

the simple name of this aggregate.

See Also:

getSignature()

getArgumentTypes

public List<DataType> getArgumentTypes()

Returns the types of this aggregate's arguments.

Returns:

the types.

getFinalFunc

public FunctionMetadata getFinalFunc()

Returns the final function of this aggregate.

This is the function specified with FINALFUNC in the CREATE AGGREGATE... statement. It transforms the final value after the aggregation is complete.

Returns:

the metadata of the final function, or null if there is none.

getInitCond

public Object getInitCond()

Returns the initial state value of this aggregate.

This is the value specified with INITCOND in the CREATE AGGREGATE... statement. It's passed to the initial invocation of the state function (if that function does not accept null arguments).

The actual type of the returned object depends on the aggregate's state type and on the codec used to parse the INITCOND literal.

If, for some reason, the INITCOND literal cannot be parsed, a warning will be logged and the returned object will be the original INITCOND literal in its textual, non-parsed form.

Returns:

the initial state, or null if there is none.

getReturnType

public DataType getReturnType()

Returns the return type of this aggregate.

This is the final type of the value computed by this aggregate; in other words, the return type of the final function if it is defined, or the state type otherwise.

Returns:

the return type.

getStateFunc

public FunctionMetadata getStateFunc()

Returns the state function of this aggregate.

This is the function specified with SFUNC in the CREATE AGGREGATE... statement. It aggregates the current state with each row to produce a new state.

Returns:

the metadata of the state function.

getStateType

public DataType getStateType()

Returns the state type of this aggregate.

This is the type specified with STYPE in the CREATE AGGREGATE... statement. It defines the type of the value that is accumulated as the aggregate iterates through the rows.

Returns:

the state type.

isDeterministic

public boolean isDeterministic()

Returns:

Whether or not this aggregate is deterministic. This means that given a particular input, the aggregate will always produce the same output.

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object