Package net.sf.saxon.value
Class EmptySequence<T extends Item>
java.lang.Object
net.sf.saxon.value.Value<T>
net.sf.saxon.value.EmptySequence<T>
- All Implemented Interfaces:
GroundedValue<T>
,ValueRepresentation<T>
An EmptySequence object represents a sequence containing no members.
-
Field Summary
Fields inherited from class net.sf.saxon.value.Value
INDETERMINATE_ORDERING
Fields inherited from interface net.sf.saxon.om.ValueRepresentation
EMPTY_VALUE_ARRAY
-
Method Summary
Modifier and TypeMethodDescriptionasItem()
Return the value in the form of an Itemboolean
Get the effective boolean value - always falseboolean
Is this expression the same as another expression?int
Determine the static cardinalitystatic <T extends Item>
EmptySequence<T>Get the implicit instance of this classDetermine the item typefinal int
Get the length of the sequenceint
hashCode()
itemAt
(int n) Get the n'th item in the sequence (starting from 0).iterate()
Return an iteration over the sequencesubsequence
(int min, int length) Get a subsequence of the valuetoString()
Returns a string representation of the object.Methods inherited from class net.sf.saxon.value.Value
asItem, asIterator, asValue, checkPermittedContents, convertToJava, fromItem, getCanonicalLexicalRepresentation, getIterator, getSchemaComparable, getSequenceLength, getStringValue, getStringValueCS, isIdentical, process, reduce
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface net.sf.saxon.om.ValueRepresentation
getStringValue, getStringValueCS
-
Method Details
-
getInstance
Get the implicit instance of this class- Returns:
- the singular instances of this class: an empty sequence
-
iterate
Return an iteration over the sequence -
asItem
Return the value in the form of an Item -
getItemType
Determine the item type- Overrides:
getItemType
in classValue<T extends Item>
- Parameters:
th
- the type hierarchy cache- Returns:
- for the default implementation: AnyItemType (not known)
-
getCardinality
public int getCardinality()Determine the static cardinality- Overrides:
getCardinality
in classValue<T extends Item>
- Returns:
- the cardinality
-
getLength
public final int getLength()Get the length of the sequence -
equals
Is this expression the same as another expression?- Overrides:
equals
in classValue<T extends Item>
- Throws:
ClassCastException
- if the values are not comparable
-
hashCode
public int hashCode() -
effectiveBooleanValue
public boolean effectiveBooleanValue()Get the effective boolean value - always false- Overrides:
effectiveBooleanValue
in classValue<T extends Item>
- Returns:
- the effective boolean value
-
itemAt
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 interfaceGroundedValue<T extends Item>
- Overrides:
itemAt
in classValue<T extends Item>
- 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
Get a subsequence of the value- Specified by:
subsequence
in interfaceGroundedValue<T extends Item>
- Parameters:
min
- 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 returnedlength
- 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. If min is
-
toString
Returns a string representation of the object.
-