net.sf.saxon.expr
Class RangeExpression

java.lang.Object
  extended bynet.sf.saxon.expr.ComputedExpression
      extended bynet.sf.saxon.expr.BinaryExpression
          extended bynet.sf.saxon.expr.RangeExpression
All Implemented Interfaces:
Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator

public class RangeExpression
extends BinaryExpression

A RangeExpression is an expression that represents an integer sequence as a pair of end-points (for example "x to y"). If the end-points are equal, the sequence is of length one.

From Saxon 7.8, the sequence must be ascending; if the end-point is less than the start-point, an empty sequence is returned. This is to allow expressions of the form "for $i in 1 to count($seq) return ...."

See Also:
Serialized Form

Nested Class Summary
static class RangeExpression.RangeIterator
          Iterator that produces numeric values in a monotonic sequence, ascending or descending
 
Field Summary
 
Fields inherited from class net.sf.saxon.expr.BinaryExpression
operand0, operand1, operator
 
Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
 
Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
 
Constructor Summary
RangeExpression(Expression start, int op, Expression end)
          Construct a RangeExpression
 
Method Summary
 Expression analyze(StaticContext env, ItemType contextItemType)
          Type-check the expression
 int computeCardinality()
          Determine the static cardinality
 ItemType getItemType()
          Get the data type of the items returned
 SequenceIterator iterate(XPathContext context)
          Return an iteration over the sequence
 
Methods inherited from class net.sf.saxon.expr.BinaryExpression
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, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getParentExpression, getPublicId, getSpecialProperties, getSystemId, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, typeError, typeError
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

RangeExpression

public RangeExpression(Expression start,
                       int op,
                       Expression end)
Construct a RangeExpression

Method Detail

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

getItemType

public ItemType getItemType()
Get the data type of the items returned

Returns:
a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

computeCardinality

public int computeCardinality()
Determine the static cardinality

Overrides:
computeCardinality in class BinaryExpression

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException
Return an iteration over the sequence

Specified by:
iterate in interface Expression
Overrides:
iterate in class ComputedExpression
Parameters:
context - supplies the context for evaluation
Returns:
a SequenceIterator that can be used to iterate over the result of the expression
Throws:
XPathException - if any dynamic error occurs evaluating the expression