com.datastax.dse.driver.api.core.metadata.schema

Interface DseFunctionMetadata

All Superinterfaces:

Describable, FunctionMetadata

public interface DseFunctionMetadata
extends FunctionMetadata

Specialized function metadata for DSE.

It adds support for the DSE-specific DETERMINISTIC and MONOTONIC keywords.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	DseFunctionMetadata.Monotonicity The monotonicity of a function.

Method Summary

Modifier and Type	Method and Description
default String	describe(boolean pretty) Returns a single CQL statement that creates the element.
default Optional<Boolean>	getDeterministic() Indicates if this function is deterministic.
List<CqlIdentifier>	getMonotonicArgumentNames() Returns a list of argument names that are monotonic.
default Optional<DseFunctionMetadata.Monotonicity>	getMonotonicity() Returns this function's DseFunctionMetadata.Monotonicity.
boolean	isDeterministic() Deprecated. Use getDeterministic() instead.
boolean	isMonotonic() Deprecated. use getMonotonicity() instead.

Methods inherited from interface com.datastax.oss.driver.api.core.metadata.schema.FunctionMetadata

describeWithChildren, getBody, getKeyspace, getLanguage, getParameterNames, getReturnType, getSignature, isCalledOnNullInput

Method Detail

isDeterministic

@Deprecated
boolean isDeterministic()

Deprecated. Use getDeterministic() instead.

getDeterministic

default Optional<Boolean> getDeterministic()

Indicates if this function is deterministic. A deterministic function means that given a particular input, the function will always produce the same output.

This method returns empty if this information was not found in the system tables, regardless of the actual function characteristics; this is the case for all versions of DSE older than 6.0.0.

Returns:

Whether or not this function is deterministic; or empty if such information is not available in the system tables.

isMonotonic

@Deprecated
boolean isMonotonic()

Deprecated. use getMonotonicity() instead.

getMonotonicity

default Optional<DseFunctionMetadata.Monotonicity> getMonotonicity()

Returns this function's DseFunctionMetadata.Monotonicity.

A function can be either:

• fully monotonic. In that case, this method returns DseFunctionMetadata.Monotonicity.FULLY_MONOTONIC, and getMonotonicArgumentNames() returns all the arguments;
• partially monotonic, meaning that partial application over some of the arguments is monotonic. Currently (DSE 6.0.0), CQL only allows partial monotonicity on exactly one argument. This may change in a future CQL version. In that case, this method returns DseFunctionMetadata.Monotonicity.PARTIALLY_MONOTONIC, and getMonotonicArgumentNames() returns a singleton list;
• not monotonic. In that case, this method return DseFunctionMetadata.Monotonicity.NOT_MONOTONIC and getMonotonicArgumentNames() returns an empty list.

Full monotonicity is required to use the function in a GROUP BY clause.

This method returns empty if this information was not found in the system tables, regardless of the actual function characteristics; this is the case for all versions of DSE older than 6.0.0.

Returns:

this function's DseFunctionMetadata.Monotonicity; or empty if such information is not available in the system tables.

getMonotonicArgumentNames

@NonNull
List<CqlIdentifier> getMonotonicArgumentNames()

Returns a list of argument names that are monotonic.

See getMonotonicity() for explanations on monotonicity, and the possible values returned by this method.

NOTE: For versions of DSE older than 6.0.0, this method will always return an empty list, regardless of the actual function characteristics.

Returns:

the argument names that the function is monotonic on.

describe

@NonNull
default String describe(boolean pretty)

Description copied from interface: Describable

Returns a single CQL statement that creates the element.

Specified by:

describe in interface Describable

Specified by:

describe in interface FunctionMetadata

Parameters:

pretty - if true, make the output more human-readable (line breaks, indents, and pretty identifiers). If false, return the statement on a single line with minimal formatting.