public class CompareToIntegerConstant extends Expression implements ComparisonExpression
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
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CompareToIntegerConstant(Expression operand,
int operator,
long comparand)
Create the expression
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protected int |
computeCardinality()
Compute the static cardinality of this expression
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int |
computeDependencies()
Compute the dependencies of an expression, as the union of the
dependencies of its subexpressions.
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int |
computeSpecialProperties()
Compute the special properties of this expression.
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boolean |
convertsUntypedToOther()
Determine whether untyped atomic values should be converted to the type of the other operand
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Expression |
copy()
Copy an expression.
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boolean |
effectiveBooleanValue(XPathContext context)
Get the effective boolean value of the expression.
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Item |
evaluateItem(XPathContext context)
Evaluate an expression as a single item.
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void |
explain(ExpressionPresenter destination)
Diagnostic print of expression structure.
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AtomicComparer |
getAtomicComparer()
Get the AtomicComparer used to compare atomic values.
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long |
getComparand()
Get the integer value on the rhs of the expression
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int |
getComparisonOperator()
Get the comparison operator
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int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
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ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the expression, if possible.
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Expression |
getOperand()
Get the expression on the lhs of the comparison
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Expression[] |
getOperands()
Get the two operands of the comparison
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int |
getSingletonOperator()
Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT,
Token.FLE, Token.FGE
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java.util.Iterator |
iterateSubExpressions()
Get the immediate sub-expressions of this expression.
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Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression |
promote(PromotionOffer offer)
Offer promotion for this subexpression.
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boolean |
replaceSubExpression(Expression original,
Expression replacement)
Replace one subexpression by a replacement subexpression
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Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression.
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Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Perform type checking of an expression and its subexpressions.
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addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeStaticProperties, display, doPromotion, dynamicError, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toString, typeError
public CompareToIntegerConstant(Expression operand, int operator, long comparand)
public Expression getOperand()
public long getComparand()
public int getComparisonOperator()
public int getImplementationMethod()
getImplementationMethod
??? Expression
Expression.EVALUATE_METHOD
public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
??? Expression
visitor
- the expression visitorXPathException
- if an error is discovered during expression
rewritingpublic Expression promote(PromotionOffer offer) throws XPathException
promote
??? Expression
offer
- 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 expressionXPathException
- if any error is detectedpublic int computeSpecialProperties()
Expression
StaticProperty
. The "special" properties are properties
other than cardinality and dependencies, and most of them relate to properties of node sequences, for
example whether the nodes are in document order.computeSpecialProperties
??? Expression
public int computeDependencies()
computeDependencies
??? Expression
public Expression copy()
copy
??? Expression
public java.util.Iterator iterateSubExpressions()
iterateSubExpressions
??? Expression
public boolean replaceSubExpression(Expression original, Expression replacement)
replaceSubExpression
??? Expression
original
- the original subexpressionreplacement
- the replacement subexpressionpublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
???? EvaluableItem
evaluateItem
??? Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic boolean effectiveBooleanValue(XPathContext context) throws XPathException
effectiveBooleanValue
??? Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionprotected int computeCardinality()
Expression
computeCardinality
??? Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
typeCheck
??? Expression
visitor
- the expession 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, ItemType 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
??? Expression
visitor
- the 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 ItemType getItemType(TypeHierarchy th)
This method should always return a result, though it may be the best approximation that is available at the time.
getItemType
??? Expression
th
- the type hierarchy cachepublic void explain(ExpressionPresenter destination)
explain
??? Expression
destination
- the expression presenter used to display the structurepublic AtomicComparer getAtomicComparer()
getAtomicComparer
???? ComparisonExpression
public int getSingletonOperator()
getSingletonOperator
???? ComparisonExpression
public Expression[] getOperands()
getOperands
???? ComparisonExpression
public boolean convertsUntypedToOther()
convertsUntypedToOther
???? ComparisonExpression