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: Class SingletonComparison

com.icl.saxon.expr
Class SingletonComparison


java.lang.Object

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  +--com.icl.saxon.expr.Expression

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        +--com.icl.saxon.expr.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.


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, enumerate, evaluateAsNodeSet, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SingletonComparison


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

simplify


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

evaluate


public Value evaluate(Context c)
               throws XPathException
Evaluate the expression in a given context
Overrides:
evaluate in class 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 class 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 class 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 class 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 class 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

display


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