public class GeneralComparison extends BinaryExpression implements ComparisonExpression
?????? | ????? |
---|---|
protected AtomicComparer |
comparer |
protected int |
singletonOperator |
operand0, operand1, operator
EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
?????? |
---|
GeneralComparison(Expression p0,
int op,
Expression p1)
Create a relational expression identifying the two operands and the operator
|
?????? | ????? |
---|---|
protected static boolean |
compare(AtomicValue a1,
int operator,
AtomicValue a2,
AtomicComparer comparer,
XPathContext context)
Compare two atomic values
|
int |
computeCardinality()
Determine the static cardinality.
|
boolean |
convertsUntypedToOther()
Determine whether untyped atomic values should be converted to the type of the other operand
|
Expression |
copy()
Copy an expression.
|
protected java.lang.String |
displayOperator() |
boolean |
effectiveBooleanValue(XPathContext context)
Evaluate the expression in a boolean context
|
Item |
evaluateItem(XPathContext context)
Evaluate the expression in a given context
|
AtomicComparer |
getAtomicComparer()
Get the AtomicComparer used to compare atomic values.
|
protected GeneralComparison |
getInverseComparison() |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the expression
|
int |
getSingletonOperator()
Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT,
Token.FLE, Token.FGE
|
Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Optimize the expression
|
Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Type-check the expression
|
computeSpecialProperties, equals, explain, getOperands, getOperator, hashCode, isAssociative, isCommutative, isInverse, iterateSubExpressions, promote, replaceSubExpression, setFlattened, simplify, toString
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setLocationId, staticTypeCheck, suppressValidation, typeError
getOperands
protected int singletonOperator
protected AtomicComparer comparer
public GeneralComparison(Expression p0, int op, Expression p1)
p0
- the left-hand operandop
- the operator, as a token returned by the Tokenizer (e.g. Token.LT)p1
- the right-hand operandpublic AtomicComparer getAtomicComparer()
getAtomicComparer
???? ComparisonExpression
public int getSingletonOperator()
getSingletonOperator
???? ComparisonExpression
public boolean convertsUntypedToOther()
convertsUntypedToOther
???? ComparisonExpression
public int computeCardinality()
computeCardinality
??? BinaryExpression
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
typeCheck
??? BinaryExpression
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, ItemType contextItemType) throws XPathException
optimize
??? BinaryExpression
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 copy()
copy
??? Expression
public Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
???? EvaluableItem
evaluateItem
??? Expression
context
- the given context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic boolean effectiveBooleanValue(XPathContext context) throws XPathException
effectiveBooleanValue
??? Expression
context
- the given context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionprotected static boolean compare(AtomicValue a1, int operator, AtomicValue a2, AtomicComparer comparer, XPathContext context) throws XPathException
a1
- the first valueoperator
- the operator, for example Token.EQUALS
a2
- the second valuecomparer
- the comparer to be used to perform the comparisoncontext
- the XPath evaluation contextXPathException
public ItemType getItemType(TypeHierarchy th)
getItemType
??? Expression
th
- the type hierarchy cacheprotected GeneralComparison getInverseComparison()
protected java.lang.String displayOperator()
displayOperator
??? BinaryExpression