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java.lang.Object
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+--net.sf.saxon.expr.ComputedExpression
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+--net.sf.saxon.expr.PathExpression
An expression that establishes a set of nodes by following relationships between nodes in the document. Specifically, it consists of a start expression which defines a set of nodes, and a Step which defines a relationship to be followed from those nodes to create a new set of nodes.
| Field Summary |
| Fields inherited from class net.sf.saxon.expr.ComputedExpression |
locationId, staticProperties |
| Fields inherited from interface net.sf.saxon.expr.Expression |
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD |
| Constructor Summary | |
PathExpression(Expression start,
Expression step)
Constructor |
|
| Method Summary | |
Expression |
analyze(StaticContext env,
ItemType contextItemType)
Type-check the expression |
int |
computeCardinality()
Determine the static cardinality of the expression |
int |
computeDependencies()
Determine which aspects of the context the expression depends on. |
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type). |
void |
display(int level,
NamePool pool,
java.io.PrintStream out)
Diagnostic print of expression structure |
boolean |
equals(java.lang.Object other)
Is this expression the same as another expression? |
Expression |
getFirstStep()
Get the first step in this expression. |
ItemType |
getItemType()
Determine the data type of the items returned by this exprssion |
Expression |
getRemainingSteps()
Get all steps after the first. |
int |
hashCode()
get HashCode for comparing two expressions |
SequenceIterator |
iterate(XPathContext context)
Iterate the path-expression in a given context |
java.util.Iterator |
iterateSubExpressions()
Get the immediate subexpressions of this expression |
java.lang.Object |
map(Item item,
XPathContext context,
java.lang.Object info)
Mapping function, from a node returned by the start iteration, to a sequence returned by the child. |
Expression |
promote(PromotionOffer offer)
Promote this expression if possible |
Expression |
simplify(StaticContext env)
Simplify an expression |
| Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
public PathExpression(Expression start,
Expression step)
start - A node-set expression denoting the absolute or relative set of nodes from which the
navigation path should start.step - The step to be followed from each node in the start expression to yield a new
node-set| Method Detail |
public final ItemType getItemType()
getItemType in interface Expression
public Expression simplify(StaticContext env)
throws XPathException
simplify in interface Expressionsimplify in class ComputedExpressionXPathException - if an error is discovered during expression
rewriting
public Expression analyze(StaticContext env,
ItemType contextItemType)
throws XPathException
analyze in interface Expressionenv - the static context of the expressioncontextItemType - 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
XPathException
public Expression promote(PromotionOffer offer)
throws XPathException
promote in interface Expressionpromote in class ComputedExpressionoffer - details of the offer, for example the offer to move
expressions that don't depend on the context to an outer level in
the containing expression
XPathException - if any error is detectedpublic java.util.Iterator iterateSubExpressions()
iterateSubExpressions in interface ExpressioniterateSubExpressions in class ComputedExpressionpublic int computeDependencies()
computeDependencies in class ComputedExpressionpublic int computeSpecialProperties()
computeSpecialProperties in class ComputedExpressionpublic int computeCardinality()
computeCardinality in class ComputedExpressionpublic boolean equals(java.lang.Object other)
equals in class java.lang.Objectpublic int hashCode()
hashCode in class java.lang.Objectpublic Expression getFirstStep()
public Expression getRemainingSteps()
public SequenceIterator iterate(XPathContext context)
throws XPathException
iterate in interface Expressioniterate in class ComputedExpressioncontext - the evaluation context
XPathException - if any dynamic error occurs evaluating the
expression
public java.lang.Object map(Item item,
XPathContext context,
java.lang.Object info)
throws XPathException
map in interface MappingFunctionitem - The item to be mapped.
If context is supplied, this must be the same as context.currentItem().context - The processing context. This is supplied only for mapping constructs that
set the context node, position, and size. Otherwise it is null.info - Arbitrary information supplied by the creator of the MappingIterator. It must be
read-only and immutable for the duration of the iteration.
XPathException
public void display(int level,
NamePool pool,
java.io.PrintStream out)
display in interface Expressionlevel - indentation level for this expressionpool - NamePool used to expand any names appearing in the expressionout - Output destination
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