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java.lang.Objectnet.sf.saxon.expr.Expression
net.sf.saxon.expr.UnaryExpression
net.sf.saxon.expr.CastingExpression
net.sf.saxon.expr.CastableExpression
public final class CastableExpression
Castable Expression: implements "Expr castable as atomic-type?". The implementation simply wraps a cast expression with a try/catch.
| Field Summary |
|---|
| Fields inherited from class net.sf.saxon.expr.CastingExpression |
|---|
converter, nsResolver |
| 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 | |
|---|---|
CastableExpression(Expression source,
AtomicType target,
boolean allowEmpty)
Create a "castable" expression of the form "source castable as target" |
|
| Method Summary | |
|---|---|
int |
computeCardinality()
Determine the static cardinality. |
Expression |
copy()
Copy an expression. |
boolean |
effectiveBooleanValue(XPathContext context)
Get the effective boolean value of the expression. |
boolean |
equals(Object other)
Is this expression the same as another expression? |
Item |
evaluateItem(XPathContext context)
Evaluate the expression |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the result of the Castable expression |
int |
hashCode()
get HashCode for comparing two expressions. |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Optimize the expression |
protected Expression |
preEvaluate()
|
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 net.sf.saxon.expr.CastingExpression |
|---|
allowsEmpty, computeSpecialProperties, getConverter, getNamespaceResolver, getTargetPrimitiveType, getTargetType, isOperandIsStringLiteral, setAllowEmpty, setNamespaceResolver, setOperandIsStringLiteral, setTargetType, simplify |
| Methods inherited from class net.sf.saxon.expr.UnaryExpression |
|---|
displayOperator, getBaseExpression, iterateSubExpressions, promote, replaceSubExpression |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public CastableExpression(Expression source,
AtomicType target,
boolean allowEmpty)
source - The source expressiontarget - The type being tested againstallowEmpty - true if an empty sequence is acceptable, that is if the expression
was written as "source castable as target?"| Method Detail |
|---|
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)
protected Expression preEvaluate()
throws XPathException
XPathException
public Expression optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
throws XPathException
optimize 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 boolean equals(Object other)
equals in class UnaryExpressionpublic int hashCode()
hashCode in class UnaryExpressionpublic ItemType getItemType(TypeHierarchy th)
getItemType in class UnaryExpressionth - the type hierarchy cache
public int computeCardinality()
UnaryExpression
computeCardinality in class UnaryExpressionStaticProperty.ALLOWS_ZERO_OR_ONE,
StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE,
StaticProperty.ALLOWS_ZERO_OR_MOREpublic Expression copy()
Expression
copy in class Expression
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 boolean effectiveBooleanValue(XPathContext context)
throws XPathException
Expression
effectiveBooleanValue in class Expressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expressionpublic String toString()
toString in class UnaryExpressionpublic void explain(ExpressionPresenter out)
explain in class UnaryExpressionout - the expression presenter used to display the structure
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