org.treetank.service.xml.xpath.expr

Class CastableExpr

java.lang.Object

org.treetank.axis.AbsAxis

org.treetank.service.xml.xpath.expr.AbsExpression

org.treetank.service.xml.xpath.expr.CastableExpr

All Implemented Interfaces:

Iterable<Long>, Iterator<Long>

public class CastableExpr
extends AbsExpression

CastableExpression

The castable expression tests whether a given value is castable into a given target type. The target type must be an atomic type that is in the in-scope schema types [err:XPST0051]. In addition, the target type cannot be xs:NOTATION or xs:anyAtomicType [err:XPST0080]. The optional occurrence indicator "?" denotes that an empty sequence is permitted.

The expression V castable as T returns true if the value V can be successfully cast into the target type T by using a cast expression; otherwise it returns false. The castable expression can be used as a predicate to avoid errors at evaluation time. It can also be used to select an appropriate type for processing of a given value.

Constructor Summary

Constructors

Constructor and Description
CastableExpr(INodeReadTrx rtx, AbsAxis inputExpr, SingleType mTarget) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
AtomicValue	evaluate() Performs the expression dependent evaluation of the expression.
void	reset(long mNodeKey) Resetting the nodekey of this axis to a given nodekey.

Methods inherited from class org.treetank.service.xml.xpath.expr.AbsExpression

hasNext

Methods inherited from class org.treetank.axis.AbsAxis

addAtomicToItemList, close, getItemList, getNode, getStartKey, isSelfIncluded, iterator, moveTo, next, remove, resetToLastKey, resetToStartKey

Methods inherited from class java.lang.Object

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

Constructor Detail

CastableExpr

public CastableExpr(INodeReadTrx rtx,
            AbsAxis inputExpr,
            SingleType mTarget)

Constructor. Initializes the internal state.

Parameters:

rtx - Exclusive (immutable) trx to iterate with.

inputExpr - input expression, that's castablity will be tested.

mTarget - Type to test, whether the input expression can be casted to.

Method Detail

reset

public void reset(long mNodeKey)

Resetting the nodekey of this axis to a given nodekey.

Overrides:

reset in class AbsExpression

Parameters:

mNodeKey - the nodekey where the reset should occur to.

evaluate

public AtomicValue evaluate()
                     throws TTXPathException

Performs the expression dependent evaluation of the expression. (Template method)

Specified by:

evaluate in class AbsExpression

Throws:

TTXPathException - if evaluation fails.