java.io.Serializable
, javax.xml.transform.SourceLocator
, LocationProvider
, SaxonLocator
, InstructionInfo
, org.xml.sax.Locator
public final class FirstItemExpression extends SingleItemFilter
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD
operand
Modifier and Type | Method | Description |
---|---|---|
Expression |
copy() |
Copy an expression.
|
Item |
evaluateItem(XPathContext context) |
Evaluate the expression
|
java.lang.String |
getExpressionName() |
Get a name identifying the kind of expression, in terms meaningful to a user.
|
static Expression |
makeFirstItemExpression(Expression base) |
Static factory method
|
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
computeCardinality, optimize, promote
computeSpecialProperties, displayOperator, equals, explain, getBaseExpression, getItemType, hashCode, iterateSubExpressions, replaceSubExpression, simplify, toString, typeCheck
public static Expression makeFirstItemExpression(Expression base)
base
- A sequence expression denoting sequence whose first item is to be returnedpublic Expression copy()
copy
in class Expression
public Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic java.lang.String getExpressionName()
Expression
getExpressionName
in class Expression