|
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||||
java.lang.Objectnet.sf.saxon.expr.Expression
net.sf.saxon.expr.FilterExpression
public final class FilterExpression
A FilterExpression contains a base expression and a filter predicate, which may be an integer expression (positional filter), or a boolean expression (qualifier)
| Field Summary | |
|---|---|
static int |
FILTERED
|
| 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 | |
|---|---|
FilterExpression(Expression start,
Expression filter)
Constructor |
|
| Method Summary | |
|---|---|
PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. |
int |
computeCardinality()
Get the static cardinality of this 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). |
Expression |
copy()
Copy an expression. |
boolean |
equals(Object other)
Is this expression the same as another expression? |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
Expression |
getControlledExpression()
Get the subexpression that is evaluated in the new context |
Expression |
getControllingExpression()
Get the underlying expression |
String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user. |
Expression |
getFilter()
Get the filter expression |
IntegerValue[] |
getIntegerBounds()
For an expression that returns an integer or a sequence of integers, get a lower and upper bound on the values of the integers that may be returned, from static analysis. |
ItemType |
getItemType(TypeHierarchy th)
Get the data type of the items returned |
int |
hashCode()
get HashCode for comparing two expressions |
boolean |
hasLoopingSubexpression(Expression child)
Given an expression that is an immediate child of this expression, test whether the evaluation of the parent expression causes the child expression to be evaluated repeatedly |
boolean |
isFilterIsPositional()
|
boolean |
isIndependentNumericFilter()
Determine whether the filter is a simple independent numeric, that is, an expression that satisfies the following conditions: (a) its value is numeric; (b) the value does not depend on the context item or position; (c) the cardinality is zero or one. |
boolean |
isPositional(TypeHierarchy th)
Determine if the filter is positional |
boolean |
isSimpleBooleanFilter()
Test if the filter always returns a singleton boolean |
SequenceIterator |
iterate(XPathContext context)
Iterate over the results, returning them in the correct order |
Iterator<Expression> |
iterateSameFocusSubExpressions()
Get the immediate sub-expressions of this expression that are evaluated with the same focus (context item, position, and size) as the parent expression. |
Iterator<Expression> |
iterateSubExpressions()
Get the immediate subexpressions of this expression |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions. |
Expression |
promote(PromotionOffer offer,
Expression parent)
Promote this expression if possible |
boolean |
replaceSubExpression(Expression original,
Expression replacement)
Replace one subexpression by a replacement subexpression |
Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression |
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. |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Field Detail |
|---|
public static final int FILTERED
| Constructor Detail |
|---|
public FilterExpression(Expression start,
Expression filter)
start - A node-set expression denoting the absolute or relative set of nodes from which the
navigation path should start.filter - An expression defining the filter predicate| Method Detail |
|---|
public String getExpressionName()
getExpressionName in class Expressionpublic ItemType getItemType(TypeHierarchy th)
getItemType in class Expressionth - the type hierarchy cache
public Expression getControllingExpression()
getControllingExpression in interface ContextSwitchingExpressionpublic boolean isFilterIsPositional()
FilterExpressionCompilerpublic Expression getControlledExpression()
getControlledExpression in interface ContextSwitchingExpressionpublic Expression getFilter()
public boolean isPositional(TypeHierarchy th)
th - the Type Hierarchy (for cached access to type information)
public boolean isSimpleBooleanFilter()
public boolean isIndependentNumericFilter()
public Expression simplify(ExpressionVisitor visitor)
throws XPathException
simplify in class Expressionvisitor - the expression visitor
XPathException - if any failure occurs
public Expression typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
throws XPathException
typeCheck in class Expressionvisitor - the expression visitorcontextItemType - the type of the context item for this expression
XPathException - if an error is discovered during this phase
(typically a type error)
public Expression optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
throws XPathException
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
optimize in class Expressionvisitor - an expression visitorcontextItemType - 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 - if an error is discovered during this phase
(typically a type error)public IntegerValue[] getIntegerBounds()
getIntegerBounds in class Expression
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
addToPathMap in class ExpressionpathMap - the PathMap to which the expression should be addedpathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
public Expression promote(PromotionOffer offer,
Expression parent)
throws XPathException
promote in class Expressionoffer - details of the promotion that is possibleparent -
XPathException - if any error is detectedpublic Iterator<Expression> iterateSubExpressions()
iterateSubExpressions in class Expressionpublic Iterator<Expression> iterateSameFocusSubExpressions()
iterateSameFocusSubExpressions in class Expressionpublic boolean hasLoopingSubexpression(Expression child)
hasLoopingSubexpression in class Expressionchild - the immediate subexpression
public boolean replaceSubExpression(Expression original,
Expression replacement)
replaceSubExpression in class Expressionoriginal - the original subexpressionreplacement - the replacement subexpression
public int computeCardinality()
computeCardinality in class Expressionpublic int computeSpecialProperties()
computeSpecialProperties in class Expressionpublic boolean equals(Object other)
equals in class Objectother - the expression to be compared with this one
public int hashCode()
hashCode in class Object
public SequenceIterator iterate(XPathContext context)
throws XPathException
iterate in class Expressioncontext - the dynamic context for the evaluation
XPathException - if any dynamic error occurspublic int computeDependencies()
computeDependencies in class Expressionpublic Expression copy()
copy in class Expressionpublic String toString()
toString in class Expressionpublic void explain(ExpressionPresenter out)
explain in class Expressionout - the ExpressionPresenter to be used
|
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||||