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com.icl.saxon.expr

Class RelationalExpression

(package private) final class RelationalExpression
extends BinaryExpression
Relational Expression: a boolean expression that compares two expressions for equals, not-equals, greater-than or less-than.

Field Summary

Fields inherited from class com.icl.saxon.expr.BinaryExpression

operator, p1, p2

Fields inherited from class com.icl.saxon.expr.Expression

staticContext

Constructor Summary

RelationalExpression()
Default constructor
RelationalExpression(Expression p1, int op, Expression p2)
Create a relational expression identifying the two operands and the operator

Method Summary

Value
evaluate(Context c)
Evaluate the expression in a given context
boolean
evaluateAsBoolean(Context c)
Evaluate the expression in a given context
int
getDataType()
Determine the data type of the expression
Expression
reduce(int dependencies, Context context)
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
Expression
simplify()
Simplify an expression

Methods inherited from class com.icl.saxon.expr.BinaryExpression

display, getDependencies, setDetails, simplify

Methods inherited from class com.icl.saxon.expr.Expression

containsReferences, display, enumerate, evaluate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsNumber, evaluateAsString, getDataType, getDependencies, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, reduce, setStaticContext, simplify, usesCurrent

Constructor Details

RelationalExpression

public RelationalExpression()
Default constructor

RelationalExpression

public RelationalExpression(Expression p1,
                            int op,
                            Expression p2)
Create a relational expression identifying the two operands and the operator
Parameters:
p1 - the left-hand operand
op - the operator, as a token returned by the Tokenizer (e.g. Tokenizer.LT)
p2 - the right-hand operand

Method Details

evaluate

public Value evaluate(Context c)
            throws XPathException
Evaluate the expression in a given context
Overrides:
evaluate in interface Expression
Parameters:
c - the given context for evaluation
Returns:
a BooleanValue representing the result of the numeric comparison of the two operands

evaluateAsBoolean

public boolean evaluateAsBoolean(Context c)
            throws XPathException
Evaluate the expression in a given context
Overrides:
evaluateAsBoolean in interface Expression
Parameters:
c - the given context for evaluation
Returns:
a boolean representing the result of the numeric comparison of the two operands

getDataType

public int getDataType()
Determine the data type of the expression
Overrides:
getDataType in interface Expression
Returns:
Value.BOOLEAN

reduce

public Expression reduce(int dependencies,
                         Context context)
            throws XPathException
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
Overrides:
reduce in interface Expression
Parameters:
dependencies - The dependencies to be removed
context - The context to be used for the partial evaluation
Returns:
a new expression that does not have any of the specified dependencies

simplify

public Expression simplify()
            throws XPathException
Simplify an expression
Overrides:
simplify in interface BinaryExpression
Returns:
the simplified expression

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