Package net.sf.saxon.type.coercion

Class AtomicCoercionPlan

java.lang.Object

net.sf.saxon.type.coercion.CoercionPlan

net.sf.saxon.type.coercion.AtomicCoercionPlan

Direct Known Subclasses:

AnyURICoercionPlan, Base64BinaryCoercionPlan, ChoiceCoercionPlan, DecimalCoercionPlan, DerivedAtomicCoercionPlan, DoubleCoercionPlan, FloatCoercionPlan, HexBinaryCoercionPlan, QNameCoercionPlan, SingletonEnumerationCoercionPlan, StringCoercionPlan, UnionCoercionPlan

public class AtomicCoercionPlan
extends CoercionPlan

A coercion plan represents a process for implementing the coercion rules for converting a supplied value to a given required type. An AtomicCoercionPlan is used where the required item type is atomic, and is further refined for specific atomic types where special rules apply.

Constructor Summary

Constructors

Constructor	Description
AtomicCoercionPlan()

Method Summary

Modifier and Type	Method	Description
protected AtomicValue	coerceAtomicValue(AtomicValue atom, ItemType requiredType, CoercionRequest request)	Coerce an atomic value to the required atomic type.
GroundedValue	coerceItem(Item item, ItemType requiredType, CoercionRequest request)	Apply the coercion rules (function conversion rules) to a value, given a required type.
protected AtomicValue	convertUntyped(AtomicValue atom, ItemType requiredType, CoercionRequest request)	Coerce an untyped atomic value to the required atomic type.
static AtomicCoercionPlan	getInstance()
protected AtomicValue	promote(AtomicValue atom, ItemType requiredType, CoercionRequest request)	Promote an atomic value to the required atomic type.

Methods inherited from class net.sf.saxon.type.coercion.CoercionPlan

check, coerceSequence, coercionError

Methods inherited from class java.lang.Object

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

Constructor Details

AtomicCoercionPlan

public AtomicCoercionPlan()

Method Details

getInstance

public static AtomicCoercionPlan getInstance()

coerceItem

public GroundedValue coerceItem(Item item,
 ItemType requiredType,
 CoercionRequest request)
                         throws XPathException

Apply the coercion rules (function conversion rules) to a value, given a required type.

Specified by:

coerceItem in class CoercionPlan

Parameters:

item - the value to be converted

requiredType - the required type (always atomic)

request - the input to the coercion

Returns:

the converted value (possibly as a lazily-evaluated sequence)

Throws:

XPathException - if the value cannot be converted to the required type

coerceAtomicValue

protected AtomicValue coerceAtomicValue(AtomicValue atom,
 ItemType requiredType,
 CoercionRequest request)
                                 throws XPathException

Coerce an atomic value to the required atomic type. This method essentially handles conversion of untypedAtomic values to the target type, followed by type promotion (for example decimal to double).

Parameters:

atom - the atomic value to be converted

requiredType - the required atomic type

request - details of the coercion request for diagnostics

Returns:

the converted atomic value

Throws:

XPathException - if conversion fails

convertUntyped

protected AtomicValue convertUntyped(AtomicValue atom,
 ItemType requiredType,
 CoercionRequest request)
                              throws XPathException

Coerce an untyped atomic value to the required atomic type.

Parameters:

atom - the untyped atomic value to be converted

requiredType - the required atomic type

request - details of the coercion request for diagnostics

Returns:

the converted atomic value

Throws:

XPathException - if conversion fails

promote

protected AtomicValue promote(AtomicValue atom,
 ItemType requiredType,
 CoercionRequest request)
                       throws XPathException

Promote an atomic value to the required atomic type. This handles, for example, decimal to string conversion or base64Binary to hexBinary. It also handles down-casting to derived atomic types. The default implementation returns the supplied value unchanged.

Parameters:

atom - the untyped atomic value to be converted

requiredType - the required atomic type

request - details of the coercion request for diagnostics

Returns:

the converted atomic value

Throws:

XPathException - if conversion fails