com.icl.saxon.expr
Class PositionRange

java.lang.Object
  extended by com.icl.saxon.expr.Expression
      extended by com.icl.saxon.expr.PositionRange

 class PositionRange
extends Expression

PositionRange: a boolean expression that tests whether the position() is within a certain range. This expression can occur in any context but it is optimized when it appears as a predicate (see FilterEnumerator)


Field Summary
 
Fields inherited from class com.icl.saxon.expr.Expression
staticContext
 
Constructor Summary
PositionRange(int min, int max)
          Create a position range
 
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
 int getDependencies()
          Get the dependencies
protected  int getMaxPosition()
          Get the maximum position
protected  int getMinPosition()
          Get the minimum position
 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

PositionRange

public PositionRange(int min,
                     int max)
Create a position range

Method Detail

simplify

public Expression simplify()
                    throws XPathException
Simplify an expression

Overrides:
simplify in class Expression
Returns:
the simplified expression
Throws:
XPathException

evaluate

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

Specified by:
evaluate in class Expression
Parameters:
c - the given context for evaluation
Returns:
a BooleanValue representing the result of the numeric comparison of the two operands
Throws:
XPathException

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
Throws:
XPathException

getDataType

public int getDataType()
Determine the data type of the expression

Specified by:
getDataType in class Expression
Returns:
Value.BOOLEAN

getDependencies

public int getDependencies()
Get the dependencies

Specified by:
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.

Specified by:
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
Throws:
XPathException

getMinPosition

protected int getMinPosition()
Get the minimum position


getMaxPosition

protected int getMaxPosition()
Get the maximum position


display

public void display(int level)
Diagnostic print of expression structure

Specified by:
display in class Expression