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java.lang.Object net.sf.saxon.expr.Expression net.sf.saxon.expr.UnaryExpression net.sf.saxon.expr.InstanceOfExpression
public final class InstanceOfExpression
InstanceOf Expression: implements "Expr instance of data-type"
Field Summary |
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Fields inherited from class net.sf.saxon.expr.UnaryExpression |
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operand |
Fields inherited from class net.sf.saxon.expr.Expression |
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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 | |
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InstanceOfExpression(Expression source,
SequenceType target)
Construct an "instance of" expression in the form "source instance of target" |
Method Summary | |
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int |
computeCardinality()
Determine the cardinality |
Expression |
copy()
Copy an expression. |
boolean |
effectiveBooleanValue(XPathContext context)
Evaluate the expression as a boolean |
boolean |
equals(Object other)
Is this expression the same as another expression? |
Item |
evaluateItem(XPathContext context)
Evaluate the expression |
void |
explain(ExpressionPresenter destination)
Diagnostic print of expression structure. |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the result of the InstanceOf expression |
int |
getRequiredCardinality()
Get the cardinality that we are testing for membership of |
ItemType |
getRequiredItemType()
Get the item type that we are testing for membership of |
int |
hashCode()
get HashCode for comparing two expressions. |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions. |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression |
Methods inherited from class net.sf.saxon.expr.UnaryExpression |
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computeSpecialProperties, displayOperator, getBaseExpression, iterateSubExpressions, promote, replaceSubExpression, simplify, toString |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public InstanceOfExpression(Expression source, SequenceType target)
source
- the expression whose type is to be testedtarget
- the type against which it is testedMethod Detail |
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public ItemType getRequiredItemType()
public int getRequiredCardinality()
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
typeCheck
in class UnaryExpression
visitor
- 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 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 UnaryExpression
visitor
- 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 boolean equals(Object other)
equals
in class UnaryExpression
public int hashCode()
hashCode
in class UnaryExpression
public int computeCardinality()
computeCardinality
in class UnaryExpression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public Expression copy()
copy
in class Expression
public ItemType getItemType(TypeHierarchy th)
getItemType
in class UnaryExpression
th
- the type hierarchy cache
public Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluated
XPathException
- if any dynamic error occurs evaluating the
expressionpublic boolean effectiveBooleanValue(XPathContext context) throws XPathException
effectiveBooleanValue
in class Expression
context
- The context in which the expression is to be evaluated
XPathException
- if any dynamic error occurs evaluating the
expressionpublic void explain(ExpressionPresenter destination)
explain
in class UnaryExpression
destination
- the expression presenter used to display the structure
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