net.sf.saxon.value
Class IntegerRange

java.lang.Object
  net.sf.saxon.value.Value<IntegerValue>
      net.sf.saxon.value.IntegerRange

All Implemented Interfaces:

GroundedValue<IntegerValue>, ValueRepresentation<IntegerValue>

public class IntegerRange
extends Value<IntegerValue>
implements GroundedValue<IntegerValue>

This class represents a sequence of consecutive ascending integers, for example 1 to 50. The integers must be within the range of a Java long.

Field Summary

long	end
long	start

Fields inherited from class net.sf.saxon.value.Value

INDETERMINATE_ORDERING

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Constructor Summary

IntegerRange(long start, long end)
Construct an integer range expression

Method Summary

int	getCardinality() Determine the cardinality
long	getEnd() Get the last integer in the sequence (inclusive)
ItemType	getItemType(TypeHierarchy th) Determine the data type of the items in the expression, if possible
int	getLength() Get the length of the sequence
long	getStart() Get the first integer in the sequence (inclusive)
IntegerValue	itemAt(int n) Get the n'th item in the sequence (starting from 0).
SequenceIterator<IntegerValue>	iterate() Return an Iterator to iterate over the values of a sequence.
GroundedValue<IntegerValue>	subsequence(int start, int length) Get a subsequence of the value

Methods inherited from class net.sf.saxon.value.Value

asItem, asItem, asIterator, asValue, checkPermittedContents, convertToJava, effectiveBooleanValue, equals, fromItem, getCanonicalLexicalRepresentation, getIterator, getSchemaComparable, getSequenceLength, getStringValue, getStringValueCS, hashCode, isIdentical, process, reduce

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.ValueRepresentation

getStringValue, getStringValueCS

Field Detail

start

public long start

end

public long end

Constructor Detail

IntegerRange

public IntegerRange(long start,
                    long end)
             throws XPathException

Construct an integer range expression

Parameters:

start - the first integer in the sequence (inclusive)

end - the last integer in the sequence (inclusive). Must be >= start

Throws:

XPathException - if the sequence is longer than the Saxon limit (2^31)

Method Detail

getStart

public long getStart()

Get the first integer in the sequence (inclusive)

Returns:

the first integer in the sequence (inclusive)

getEnd

public long getEnd()

Get the last integer in the sequence (inclusive)

Returns:

the last integer in the sequence (inclusive)

iterate

public SequenceIterator<IntegerValue> iterate()
                                       throws XPathException

Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.

Specified by:

iterate in class Value<IntegerValue>

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

getItemType

public ItemType getItemType(TypeHierarchy th)

Determine the data type of the items in the expression, if possible

Overrides:

getItemType in class Value<IntegerValue>

Parameters:

th - the type hierarchy cache

Returns:

AnyItemType (not known)

getCardinality

public int getCardinality()

Determine the cardinality

Overrides:

getCardinality in class Value<IntegerValue>

Returns:

the cardinality

itemAt

public IntegerValue itemAt(int n)

Get the n'th item in the sequence (starting from 0). This is defined for all Values, but its real benefits come for a sequence Value stored extensionally (or for a MemoClosure, once all the values have been read)

Specified by:

itemAt in interface GroundedValue<IntegerValue>

Overrides:

itemAt in class Value<IntegerValue>

Parameters:

n - position of the required item, counting from zero.

Returns:

the n'th item in the sequence, where the first item in the sequence is numbered zero. If n is negative or >= the length of the sequence, returns null.

subsequence

public GroundedValue<IntegerValue> subsequence(int start,
                                               int length)

Get a subsequence of the value

Specified by:

subsequence in interface GroundedValue<IntegerValue>

Parameters:

start - the index of the first item to be included in the result, counting from zero. A negative value is taken as zero. If the value is beyond the end of the sequence, an empty sequence is returned

length - the number of items to be included in the result. Specify Integer.MAX_VALUE to get the subsequence up to the end of the base sequence. If the value is negative, an empty sequence is returned. If the value goes off the end of the sequence, the result returns items up to the end of the sequence

Returns:

the required subsequence.

getLength

public int getLength()

Get the length of the sequence

Specified by:

getLength in interface GroundedValue<IntegerValue>

Overrides:

getLength in class Value<IntegerValue>

Returns:

the number of items in the sequence