net.sf.saxon.functions
Class Doc

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

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, CallableExpression, InstructionInfo, Locator

public class Doc
extends SystemFunction
implements CallableExpression

Implement the fn:doc() function - a simplified form of the Document function

See Also:

Serialized Form

Field Summary

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

operation

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

argument

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

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

Constructor Summary

Doc()

Method Summary

PathMap.PathMapNodeSet	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) Add a representation of this expression to a PathMap.
SequenceIterator	call(SequenceIterator[] arguments, XPathContext context) Evaluate the expression
void	checkArguments(ExpressionVisitor visitor) Method called during static type checking
int	computeCardinality() Determine the cardinality of the function.
int	computeSpecialProperties() Get the static properties of this expression (other than its type).
Expression	copy() Copy an expression.
boolean	equals(Object o) Determine whether two expressions are equivalent
Item	evaluateItem(XPathContext context) Evaluate the expression
String	getStaticBaseURI() Get the static base URI of the expression
boolean	isReadOnce() Ask whether this document has been marked as being read once only.
Expression	preEvaluate(ExpressionVisitor visitor) preEvaluate: this method suppresses compile-time evaluation unless a configuration option has been set to allow early evaluation.
void	sendDocument(XPathContext context, Receiver out) Copy the document identified by this expression to a given Receiver.
void	setReadOnce(boolean once) Indicate that the document will be read once only (or that it should be treated as if it is read once only.

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

addContextDocumentArgument, addDocToPathMap, getDetails, getErrorCodeForTypeErrors, getImplementationMethod, getItemType, getOperation, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

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

adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, 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

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.saxon.expr.CallableExpression

getArguments

Constructor Detail

Doc

public Doc()

Method Detail

setReadOnce

public void setReadOnce(boolean once)

Indicate that the document will be read once only (or that it should be treated as if it is read once only. This means (a) the document will not be held in memory after all references to it go out of scope, and (b) if the query or transformation tries to read it again, it will get a new copy, with different node identities, and potentially with different content. It also means that the document is eligible for document projection.

Parameters:

once - true if this document is to be treated as being read once only

isReadOnce

public boolean isReadOnce()

Ask whether this document has been marked as being read once only.

Returns:

true if the document has been marked as being read once only

checkArguments

public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException

Description copied from class: SystemFunction

Method called during static type checking

Overrides:

checkArguments in class SystemFunction

Parameters:

visitor - the expression visitor

Throws:

XPathException - if the arguments are incorrect

getStaticBaseURI

public String getStaticBaseURI()

Get the static base URI of the expression

Returns:

the static base URI

preEvaluate

public Expression preEvaluate(ExpressionVisitor visitor)

preEvaluate: this method suppresses compile-time evaluation unless a configuration option has been set to allow early evaluation.

Overrides:

preEvaluate in class FunctionCall

Parameters:

visitor - an expression visitor

Returns:

the result of the early evaluation, or the original expression, or potentially a simplified expression

computeCardinality

public int computeCardinality()

Description copied from class: SystemFunction

Determine the cardinality of the function.

Overrides:

computeCardinality in class SystemFunction

Returns:

the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE

addToPathMap

public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)

Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

Overrides:

addToPathMap in class Expression

Parameters:

pathMap - the PathMap to which the expression should be added

pathMapNodeSet -

Returns:

the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Overrides:

copy in class SystemFunction

Returns:

the copy of the original expression

equals

public boolean equals(Object o)

Determine whether two expressions are equivalent

Overrides:

equals in class SystemFunction

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the expression

Overrides:

evaluateItem in class Expression

Parameters:

context - the dynamic evaluation context

Returns:

the result of evaluating the expression (a document node)

Throws:

XPathException

call

public SequenceIterator call(SequenceIterator[] arguments,
                             XPathContext context)
                      throws XPathException

Evaluate the expression

Specified by:

call in interface CallableExpression

Parameters:

arguments - the values of the arguments, supplied as SequenceIterators

context - the dynamic evaluation context

Returns:

the result of the evaluation, in the form of a SequenceIterator

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression

computeSpecialProperties

public int computeSpecialProperties()

Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.

Overrides:

computeSpecialProperties in class SystemFunction

Returns:

the special properties, as a bit-significant integer

sendDocument

public void sendDocument(XPathContext context,
                         Receiver out)
                  throws XPathException

Copy the document identified by this expression to a given Receiver. This method is used only when it is known that the document is being copied, because there is then no problem about node identity.

Parameters:

context - the XPath dynamic context

out - the destination to which the document will be sent

Throws:

XPathException