net.sf.saxon.instruct
Class QuerySimpleContentConstructor

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.instruct.SimpleContentConstructor
          net.sf.saxon.instruct.QuerySimpleContentConstructor

All Implemented Interfaces:

Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, InstructionInfoProvider

public class QuerySimpleContentConstructor
extends SimpleContentConstructor

This class implements the rules for an XQuery simple content constructor, which are used in constructing the string value of an attribute node, text node, comment node, etc, from the value of the select expression or the contained sequence constructor. These differ slightly from the XSLT rules implemented in the superclass - specifically, the sequence is simply atomized, whereas XSLT takes special steps to concatenate adjacent text nodes before inserting separators.

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

QuerySimpleContentConstructor(Expression select, Expression separator, boolean noNodeIfEmpty)

Method Summary

Item	evaluateItem(XPathContext context) Evaluate an expression as a single item.
CharSequence	expandChildren(XPathContext context) Expand the stylesheet elements subordinate to this one, returning the result as a string.
boolean	isNoNodeWhenEmpty()

Methods inherited from class net.sf.saxon.instruct.SimpleContentConstructor

display, getImplementationMethod, getItemType, getSelectExpression, getSeparatorExpression, isAtomic, isSingleton, iterateSubExpressions, optimize, promote, replaceSubExpression, simplify, typeCheck

Methods inherited from class net.sf.saxon.expr.Expression

adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation

Methods inherited from class java.lang.Object

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

Constructor Detail

QuerySimpleContentConstructor

public QuerySimpleContentConstructor(Expression select,
                                     Expression separator,
                                     boolean noNodeIfEmpty)

Method Detail

isNoNodeWhenEmpty

public boolean isNoNodeWhenEmpty()

expandChildren

public CharSequence expandChildren(XPathContext context)
                            throws XPathException

Expand the stylesheet elements subordinate to this one, returning the result as a string. The expansion must not generate any element or attribute nodes.

Parameters:

context - The dynamic context for the transformation

Throws:

XPathException

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class SimpleContentConstructor

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression