net.sf.saxon.functions
Class NormalizeSpace

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.FunctionCall
          net.sf.saxon.functions.SystemFunction
              net.sf.saxon.functions.NormalizeSpace

All Implemented Interfaces:

Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, InstructionInfoProvider

public class NormalizeSpace
extends SystemFunction

Implement the XPath normalize-space() function

See Also:

Serialized Form

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

NormalizeSpace()

Method Summary

Item	evaluateItem(XPathContext c) Evaluate in a general context
int	getIntrinsicDependencies() Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
static CharSequence	normalize(CharSequence s) The algorithm that does the work: it removes leading and trailing whitespace, and replaces internal whitespace by a single space character.
Expression	preEvaluate(StaticContext env) Pre-evaluate a function at compile time.
Expression	typeCheck(StaticContext env, ItemType contextItemType) Type-check the expression.

Methods inherited from class net.sf.saxon.functions.SystemFunction

checkArguments, computeCardinality, computeSpecialProperties, display, getDetails, getErrorCodeForTypeErrors, getItemType, main, makeSystemFunction, optimize, setDetails

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

getArguments, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplify

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

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, 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

NormalizeSpace

public NormalizeSpace()

Method Detail

getIntrinsicDependencies

public int getIntrinsicDependencies()

Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

Overrides:

getIntrinsicDependencies in class Expression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

typeCheck

public Expression typeCheck(StaticContext env,
                            ItemType contextItemType)
                     throws XPathException

Description copied from class: FunctionCall

Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.

Overrides:

typeCheck in class FunctionCall

Parameters:

env - the static context of the expression

contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

StaticError - if an error is discovered during this phase (typically a type error)

XPathException

preEvaluate

public Expression preEvaluate(StaticContext env)
                       throws XPathException

Pre-evaluate a function at compile time. Functions that do not allow pre-evaluation, or that need access to context information, can override this method.

Overrides:

preEvaluate in class FunctionCall

Throws:

XPathException

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException

Evaluate in a general context

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class Expression

Parameters:

c - 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

normalize

public static CharSequence normalize(CharSequence s)

The algorithm that does the work: it removes leading and trailing whitespace, and replaces internal whitespace by a single space character. The code is optimized for two special cases: where the string is all whitespace, and where it contains no spaces at all (including the case where it is empty). In these two cases it avoids creating a new object.