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com.icl.saxon.expr

Class SingletonComparison

public class SingletonComparison
extends Expression
Singleton Comparison: A Relational Expression that compares a singleton node-set with a string or numeric value for equals, not-equals, greater-than or less-than.

Field Summary

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

staticContext

Constructor Summary

SingletonComparison(SingletonExpression p1, int op, Value p2)

Method Summary

void
display(int level)
Diagnostic print of expression structure
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, if possible
int
getDependencies()
Determine which aspects of the context the expression depends on.
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.Expression

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

Constructor Details

SingletonComparison

public SingletonComparison(SingletonExpression p1,
                           int op,
                           Value p2)

Method Details

display

public void display(int level)
Diagnostic print of expression structure
Overrides:
display in interface Expression

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 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, if possible
Overrides:
getDataType in interface Expression

Returns:
Value.BOOLEAN

getDependencies

public int getDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE
Overrides:
getDependencies in interface Expression

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 Expression

Returns:
the simplified expression

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