net.sf.saxon.expr

Class RootExpression

Implemented Interfaces:
EvaluableItem, InstructionInfoProvider, SequenceIterable, Serializable, SourceLocator

public class RootExpression
extends SingleNodeExpression

An expression whose value is always a set of nodes containing a single node, the document root. This corresponds to the XPath Expression "/", including the implicit "/" at the start of a path expression with a leading "/".

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD, locationId, staticProperties

Method Summary

PathMap.PathMapNodeSet
addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
int
computeCardinality()
Specify that the expression returns a singleton
Expression
copy()
Copy an expression.
boolean
equals(Object other)
Is this expression the same as another expression?
void
explain(ExpressionPresenter destination)
Diagnostic print of expression structure.
int
getIntrinsicDependencies()
Determine which aspects of the context the expression depends on.
ItemType
getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression
NodeInfo
getNode(XPathContext context)
Return the first element selected by this Expression
int
hashCode()
get HashCode for comparing two expressions
String
toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.

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

computeCardinality, computeSpecialProperties, effectiveBooleanValue, evaluateItem, getIntrinsicDependencies, getItemType, getNode, iterate, optimize, typeCheck

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

addToPathMap, adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, optimize, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Method Details

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 interface 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

computeCardinality

public final int computeCardinality()
Specify that the expression returns a singleton
Overrides:
computeCardinality in interface SingleNodeExpression

copy

public Expression copy()
Copy an expression. This makes a deep copy.
Overrides:
copy in interface Expression
Returns:
the copy of the original expression

equals

public boolean equals(Object other)
Is this expression the same as another expression?

explain

public void explain(ExpressionPresenter destination)
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
Overrides:
explain in interface Expression

getIntrinsicDependencies

public int getIntrinsicDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as StaticProperty.VARIABLES and StaticProperty.CURRENT_NODE
Overrides:
getIntrinsicDependencies in interface SingleNodeExpression

getItemType

public ItemType getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression
Overrides:
getItemType in interface SingleNodeExpression
Parameters:
th - the type hierarchy cache
Returns:
Type.NODE

getNode

public NodeInfo getNode(XPathContext context)
            throws XPathException
Return the first element selected by this Expression
Overrides:
getNode in interface SingleNodeExpression
Parameters:
context - The evaluation context
Returns:
the NodeInfo of the first selected element, or null if no element is selected

hashCode

public int hashCode()
get HashCode for comparing two expressions

toString

public String toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. In the case of XSLT instructions, the toString() method gives an abstracted view of the syntax
Overrides:
toString in interface Expression