mondrian.olap.type
Class TypeUtil

java.lang.Object
  mondrian.olap.type.TypeUtil

public class TypeUtil
extends Object

Utility methods relating to types.

Since:

Feb 17, 2005

Author:

jhyde

Constructor Summary

TypeUtil()

Method Summary

static boolean	canConvert(int from, int to, int[] conversionCount) Returns whether we can convert an argument of a given category to a given parameter category.
static boolean	canEvaluate(Type type) Returns whether a value of a given type can be evaluated to a scalar value.
static Type	computeCommonType(boolean allowConversions, Type... types) Returns a type sufficiently broad to hold any value of several types, but as narrow as possible.
static boolean	couldBeMember(Type type)
static boolean	isSet(Type type) Returns whether a type is a set type.
static boolean	isUnionCompatible(Type type1, Type type2) Returns whether this type is union-compatible with another.
(package private) static <T> T	neq(T t1, T t2)
static Type	stripSetType(Type type) Given a set type, returns the element type.
static Type	toMemberOrTupleType(Type type) Converts a type to a member or tuple type.
static MemberType	toMemberType(Type type) Converts a type to a member type.
static int	typeToCategory(Type type) Converts a Type value to a Category ordinal.
static Hierarchy	typeToHierarchy(Type type)

Methods inherited from class java.lang.Object

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

Constructor Detail

TypeUtil

public TypeUtil()

Method Detail

typeToHierarchy

public static Hierarchy typeToHierarchy(Type type)

stripSetType

public static Type stripSetType(Type type)

Given a set type, returns the element type. Or its element type, if it is a set type. And so on.

Parameters:

type - Type

Returns:

underlying element type which is not a set type

toMemberOrTupleType

public static Type toMemberOrTupleType(Type type)

Converts a type to a member or tuple type. If it cannot, returns null.

Parameters:

type - Type

Returns:

member or tuple type

toMemberType

public static MemberType toMemberType(Type type)

Converts a type to a member type. If it is a set, strips the set. If it is a member type, returns the type unchanged. If it is a dimension, hierarchy or level type, converts it to a member type. If it is a tuple, number, string, or boolean, returns null.

Parameters:

type - Type

Returns:

type as a member type

isUnionCompatible

public static boolean isUnionCompatible(Type type1,
                                        Type type2)

Returns whether this type is union-compatible with another. In general, to be union-compatible, types must have the same dimensionality.

Parameters:

type1 - First type

type2 - Second type

Returns:

whether types are union-compatible

canEvaluate

public static boolean canEvaluate(Type type)

Returns whether a value of a given type can be evaluated to a scalar value.

The rules are as follows:

• Clearly boolean, numeric and string expressions can be evaluated.
• Member and tuple expressions can be interpreted as a scalar value. The expression is evaluated to establish the context where a measure can be evaluated.
• Hierarchy and dimension expressions are implicitly converted into the current member, and evaluated as above.
• Level expressions cannot be evaluated
• Cube and Set (even sets with a single member) cannot be evaluated.

Parameters:

type - Type

Returns:

Whether an expression of this type can be evaluated to yield a scalar value.

isSet

public static boolean isSet(Type type)

Returns whether a type is a set type.

Parameters:

type - Type

Returns:

Whether a value of this type can be evaluated to yield a set.

couldBeMember

public static boolean couldBeMember(Type type)

typeToCategory

public static int typeToCategory(Type type)

Converts a Type value to a Category ordinal.

Parameters:

type - Type

Returns:

category ordinal

computeCommonType

public static Type computeCommonType(boolean allowConversions,
                                     Type... types)

Returns a type sufficiently broad to hold any value of several types, but as narrow as possible. If there is no such type, returns null.

The result is equivalent to calling Type.computeCommonType(Type, int[]) pairwise.

Parameters:

allowConversions - Whether to allow implicit conversions

types - Array of types

Returns:

Most general type which encompases all types

canConvert

public static boolean canConvert(int from,
                                 int to,
                                 int[] conversionCount)

Returns whether we can convert an argument of a given category to a given parameter category.

Parameters:

from - actual argument category

to - formal parameter category

conversionCount - in/out count of number of conversions performed; is incremented if the conversion is non-trivial (for example, converting a member to a level).

Returns:

whether can convert from 'from' to 'to'

neq

static <T> T neq(T t1,
                 T t2)