org.eigenbase.reltype
Class RelDataTypeImpl

java.lang.Object
  org.eigenbase.reltype.RelDataTypeImpl

All Implemented Interfaces:

RelDataType, RelDataTypeFamily

Direct Known Subclasses:

AbstractSqlType, OJTypeFactoryImpl.OJScalarType, RelCrossType, RelDataTypeFactoryImpl.JavaType, RelRecordType

public abstract class RelDataTypeImpl
extends Object
implements RelDataType, RelDataTypeFamily

RelDataTypeImpl is an abstract base for implementations of RelDataType.

Identity is based upon the digest field, which each derived class should set during construction.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/reltype/RelDataTypeImpl.java#19 $

Author:

jhyde

Field Summary

protected String	digest
protected List<RelDataTypeField>	fieldList
protected RelDataTypeField[]	fields

Constructor Summary

protected	RelDataTypeImpl() Default constructor, to allow derived classes such as BasicSqlType to be Serializable.
protected	RelDataTypeImpl(RelDataTypeField[] fields) Creates a RelDataTypeImpl.

Method Summary

protected void	computeDigest() Computes the digest field.
boolean	equals(Object obj)
protected abstract void	generateTypeString(StringBuilder sb, boolean withDetail) Generates a string representation of this type.
Charset	getCharset() Gets this type's character set, or null if this type cannot carry a character set or has no character set defined.
SqlCollation	getCollation() Gets this type's collation, or null if this type cannot carry a collation or has no collation defined.
RelDataTypeComparability	getComparability()
RelDataType	getComponentType() Gets the component type if this type is a collection, otherwise null.
RelDataTypeFamily	getFamily() Gets a canonical object representing the family of this type.
RelDataTypeField	getField(String fieldName) Looks up a field by name.
int	getFieldCount() Returns the number of fields in a struct type.
List<RelDataTypeField>	getFieldList() Gets the fields in a struct type.
int	getFieldOrdinal(String fieldName) Looks up the ordinal of a field by name.
RelDataTypeField[]	getFields() Gets the fields in a struct type.
String	getFullTypeString() Gets a string representation of this type with full detail such as character set and nullability.
SqlIntervalQualifier	getIntervalQualifier() Gets this type's interval qualifier, or null if this is not an interval type.
RelDataTypePrecedenceList	getPrecedenceList()
int	getPrecision() Gets the JDBC-defined precision for values of this type.
int	getScale() Gets the scale of this type.
SqlIdentifier	getSqlIdentifier() Gets the SqlIdentifier associated with this type.
SqlTypeName	getSqlTypeName() Gets the SqlTypeName of this type.
int	hashCode()
boolean	isNullable() Queries whether this type allows null values.
boolean	isStruct() Queries whether this is a structured type.
String	toString() Gets a string representation of this type without detail such as character set and nullability.

Methods inherited from class java.lang.Object

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

Field Detail

fields

protected RelDataTypeField[] fields

fieldList

protected List<RelDataTypeField> fieldList

digest

protected String digest

Constructor Detail

RelDataTypeImpl

protected RelDataTypeImpl(RelDataTypeField[] fields)

Creates a RelDataTypeImpl.

Parameters:

fields - Array of fields

RelDataTypeImpl

protected RelDataTypeImpl()

Default constructor, to allow derived classes such as BasicSqlType to be Serializable.

(The serialization specification says that a class can be serializable even if its base class is not serializable, provided that the base class has a public or protected zero-args constructor.)

Method Detail

getField

public RelDataTypeField getField(String fieldName)

Description copied from interface: RelDataType

Looks up a field by name.

Specified by:

getField in interface RelDataType

Parameters:

fieldName - name of field to find

Returns:

named field, or null if not found

getFieldOrdinal

public int getFieldOrdinal(String fieldName)

Description copied from interface: RelDataType

Looks up the ordinal of a field by name.

Specified by:

getFieldOrdinal in interface RelDataType

Parameters:

fieldName - name of field to find

Returns:

0-based ordinal of named field, or -1 if not found

getFieldList

public List<RelDataTypeField> getFieldList()

Description copied from interface: RelDataType

Gets the fields in a struct type. The field count is equal to the size of the returned list.

Specified by:

getFieldList in interface RelDataType

Returns:

read-only list of fields

getFields

public RelDataTypeField[] getFields()

Description copied from interface: RelDataType

Gets the fields in a struct type. The field count is equal to the length of the returned array.

NOTE jvs 17-Dec-2004: this method will become deprecated once we move to Java generics, and eventually eliminated

Specified by:

getFields in interface RelDataType

Returns:

array of fields

getFieldCount

public int getFieldCount()

Description copied from interface: RelDataType

Returns the number of fields in a struct type.

This method is equivalent to RelDataType.getFieldList() ().size().

Specified by:

getFieldCount in interface RelDataType

getComponentType

public RelDataType getComponentType()

Description copied from interface: RelDataType

Gets the component type if this type is a collection, otherwise null.

Specified by:

getComponentType in interface RelDataType

Returns:

canonical type descriptor for components

isStruct

public boolean isStruct()

Description copied from interface: RelDataType

Queries whether this is a structured type.

Specified by:

isStruct in interface RelDataType

Returns:

whether this type has fields; examples include rows and user-defined structured types in SQL, and classes in Java

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getFullTypeString

public String getFullTypeString()

Description copied from interface: RelDataType

Gets a string representation of this type with full detail such as character set and nullability. The string must serve as a "digest" for this type, meaning two types can be considered identical iff their digests are equal.

Specified by:

getFullTypeString in interface RelDataType

Returns:

full type string

isNullable

public boolean isNullable()

Description copied from interface: RelDataType

Queries whether this type allows null values.

Specified by:

isNullable in interface RelDataType

Returns:

whether type allows null values

getCharset

public Charset getCharset()

Description copied from interface: RelDataType

Gets this type's character set, or null if this type cannot carry a character set or has no character set defined.

Specified by:

getCharset in interface RelDataType

Returns:

charset of type

getCollation

public SqlCollation getCollation()
                          throws RuntimeException

Description copied from interface: RelDataType

Gets this type's collation, or null if this type cannot carry a collation or has no collation defined.

Specified by:

getCollation in interface RelDataType

Returns:

collation of type

Throws:

RuntimeException

getIntervalQualifier

public SqlIntervalQualifier getIntervalQualifier()

Description copied from interface: RelDataType

Gets this type's interval qualifier, or null if this is not an interval type.

Specified by:

getIntervalQualifier in interface RelDataType

Returns:

interval qualifier

getPrecision

public int getPrecision()

Description copied from interface: RelDataType

Gets the JDBC-defined precision for values of this type. Note that this is not always the same as the user-specified precision. For example, the type INTEGER has no user-specified precision, but this method returns 10 for an INTEGER type.

Specified by:

getPrecision in interface RelDataType

Returns:

number of decimal digits for exact numeric types; number of decimal digits in mantissa for approximate numeric types; number of decimal digits for fractional seconds of datetime types; length in characters for character types; length in bytes for binary types; length in bits for bit types; 1 for BOOLEAN

getScale

public int getScale()

Description copied from interface: RelDataType

Gets the scale of this type.

Specified by:

getScale in interface RelDataType

Returns:

number of digits of scale

getSqlTypeName

public SqlTypeName getSqlTypeName()

Description copied from interface: RelDataType

Gets the SqlTypeName of this type.

Specified by:

getSqlTypeName in interface RelDataType

Returns:

SqlTypeName, or null if this is not an SQL predefined type

getSqlIdentifier

public SqlIdentifier getSqlIdentifier()

Description copied from interface: RelDataType

Gets the SqlIdentifier associated with this type. For a predefined type, this is a simple identifier based on RelDataType.getSqlTypeName(). For a user-defined type, this is a compound identifier which uniquely names the type.

Specified by:

getSqlIdentifier in interface RelDataType

Returns:

SqlIdentifier, or null if this is not an SQL type

getFamily

public RelDataTypeFamily getFamily()

Description copied from interface: RelDataType

Gets a canonical object representing the family of this type. Two values can be compared if and only if their types are in the same family.

Specified by:

getFamily in interface RelDataType

Returns:

canonical object representing type family

generateTypeString

protected abstract void generateTypeString(StringBuilder sb,
                                           boolean withDetail)

Generates a string representation of this type.

Parameters:

sb - StringBuffer into which to generate the string

withDetail - when true, all detail information needed to compute a unique digest (and return from getFullTypeString) should be included;

computeDigest

protected void computeDigest()

Computes the digest field. This should be called in every non-abstract subclass constructor once the type is fully defined.

toString

public String toString()

Description copied from interface: RelDataType

Gets a string representation of this type without detail such as character set and nullability.

Specified by:

toString in interface RelDataType

Overrides:

toString in class Object

Returns:

abbreviated type string

getPrecedenceList

public RelDataTypePrecedenceList getPrecedenceList()

Specified by:

getPrecedenceList in interface RelDataType

Returns:

precedence list for this type

getComparability

public RelDataTypeComparability getComparability()

Specified by:

getComparability in interface RelDataType

Returns:

the category of comparison operators which make sense when applied to values of this type