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java.lang.Objectnet.sf.saxon.expr.Expression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.ItemChecker
public final class ItemChecker
A ItemChecker implements the item type checking of "treat as": that is, it returns the supplied sequence, checking that all its items are of the correct type
| Field Summary |
|---|
| Fields inherited from class net.sf.saxon.expr.UnaryExpression |
|---|
operand |
| 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 | |
|---|---|
ItemChecker(Expression sequence,
ItemType itemType,
RoleLocator role)
Constructor |
|
| Method Summary | |
|---|---|
Expression |
copy()
Copy an expression. |
boolean |
equals(Object other)
Is this expression the same as another expression? |
Item |
evaluateItem(XPathContext context)
Evaluate as an Item. |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user. |
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). |
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)
Determine the data type of the items returned by the expression |
ItemMappingFunction |
getMappingFunction(XPathContext context)
Get the mapping function used to implement this item check. |
ItemType |
getRequiredType()
Get the required type |
RoleLocator |
getRoleLocator()
Get the RoleLocator (used to construct error messages) |
int |
hashCode()
get HashCode for comparing two expressions. |
SequenceIterator |
iterate(XPathContext context)
Iterate over the sequence of values |
void |
process(XPathContext context)
Process the instruction, without returning any tail calls |
Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression |
| Methods inherited from class net.sf.saxon.expr.UnaryExpression |
|---|
computeCardinality, computeSpecialProperties, displayOperator, getBaseExpression, iterateSubExpressions, optimize, promote, replaceSubExpression, toString |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public ItemChecker(Expression sequence,
ItemType itemType,
RoleLocator role)
sequence - the expression whose value we are checkingitemType - the required type of the items in the sequencerole - information used in constructing an error message| Method Detail |
|---|
public ItemType getRequiredType()
public RoleLocator getRoleLocator()
public Expression simplify(ExpressionVisitor visitor)
throws XPathException
simplify in class UnaryExpressionvisitor - an expression visitor
XPathException - if an error is discovered during expression
rewriting
public Expression typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
throws XPathException
typeCheck in class UnaryExpressionvisitor - 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 int getImplementationMethod()
getImplementationMethod in class ExpressionExpression.ITERATE_METHOD or Expression.EVALUATE_METHOD or
Expression.PROCESS_METHODpublic IntegerValue[] getIntegerBounds()
getIntegerBounds in class Expression
public SequenceIterator iterate(XPathContext context)
throws XPathException
iterate in class Expressioncontext - supplies the context for evaluation
XPathException - if any dynamic error occurs evaluating the
expressionpublic ItemMappingFunction getMappingFunction(XPathContext context)
context - The dynamic context used to evaluate the mapping function
public Item evaluateItem(XPathContext context)
throws XPathException
evaluateItem in class Expressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expression
public void process(XPathContext context)
throws XPathException
process in class Expressioncontext - The dynamic context, giving access to the current node,
the current variables, etc.
XPathException - if a dynamic error occurspublic Expression copy()
copy in class Expressionpublic ItemType getItemType(TypeHierarchy th)
getItemType in class UnaryExpressionth - the type hierarchy cache
public boolean equals(Object other)
equals in class UnaryExpressionpublic int hashCode()
hashCode in class UnaryExpressionpublic void explain(ExpressionPresenter out)
explain in class UnaryExpressionout - the expression presenter used to display the structurepublic String getExpressionName()
getExpressionName in class Expression
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