net.sf.saxon.expr
Class ValueComparison
java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.BinaryExpression
net.sf.saxon.expr.ValueComparison
- All Implemented Interfaces:
- Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator
- public final class ValueComparison
- extends BinaryExpression
ValueComparison: a boolean expression that compares two atomic values
for equals, not-equals, greater-than or less-than. Implements the operators
eq, ne, lt, le, gt, ge
- See Also:
- Serialized Form
Methods inherited from class net.sf.saxon.expr.BinaryExpression |
computeCardinality, computeSpecialProperties, display, displayOperator, equals, getOperands, getOperator, hashCode, isCommutative, isInverse, iterateSubExpressions, promote, simplify |
Methods inherited from class net.sf.saxon.expr.ComputedExpression |
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, dynamicError, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getParentExpression, getPublicId, getSpecialProperties, getSystemId, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, typeError, typeError |
Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
ValueComparison
public ValueComparison(Expression p1,
int op,
Expression p2)
- Create a relational expression identifying the two operands and the operator
- Parameters:
p1
- the left-hand operandop
- the operator, as a token returned by the Tokenizer (e.g. Token.LT)p2
- the right-hand operand
analyze
public Expression analyze(StaticContext env,
ItemType contextItemType)
throws XPathException
- Type-check the expression
- Specified by:
analyze
in interface Expression
- Overrides:
analyze
in class BinaryExpression
- Throws:
XPathException
effectiveBooleanValue
public boolean effectiveBooleanValue(XPathContext context)
throws XPathException
- Evaluate the expression in a boolean context
- Specified by:
effectiveBooleanValue
in interface Expression
- Overrides:
effectiveBooleanValue
in class ComputedExpression
- Parameters:
context
- the given context for evaluation
- Returns:
- a boolean representing the result of the numeric comparison of the two operands
- Throws:
XPathException
- if any dynamic error occurs evaluating the
expression
evaluateItem
public Item evaluateItem(XPathContext context)
throws XPathException
- Evaluate the expression in a given context
- Specified by:
evaluateItem
in interface Expression
- Overrides:
evaluateItem
in class ComputedExpression
- Parameters:
context
- the given context for evaluation
- Returns:
- a BooleanValue representing the result of the numeric comparison of the two operands,
or null representing the empty sequence
- Throws:
XPathException
- if any dynamic error occurs evaluating the
expression
getItemType
public ItemType getItemType()
- Determine the data type of the expression
- Returns:
- Type.BOOLEAN