Class ZeroOrMore<T extends Item>

java.lang.Object
net.sf.saxon.om.ZeroOrMore<T>
All Implemented Interfaces:
Iterable<T>, GroundedValue, Sequence

public class ZeroOrMore<T extends Item> extends Object implements GroundedValue, Iterable<T>
A value that is a sequence containing one or more items. The main use is in declarations of reflexive extension functions, where declaring an argument of type <ZeroOrMore<IntegerValue>> triggers automatic type checking in the same way as for a native XSLT/XQuery function declaring the type as xs:integer*.
  • Constructor Details

    • ZeroOrMore

      public ZeroOrMore(T[] content)
      Create a sequence containing zero or one items
      Parameters:
      content - The content of the sequence
    • ZeroOrMore

      public ZeroOrMore(List<T> content)
    • ZeroOrMore

      public ZeroOrMore(SequenceIterator iter) throws XPathException
      Throws:
      XPathException
  • Method Details

    • head

      public T head()
      Description copied from interface: GroundedValue
      Get the first item of the sequence. This differs from the parent interface in not allowing an exception
      Specified by:
      head in interface GroundedValue
      Specified by:
      head in interface Sequence
      Returns:
      the first item of the sequence, or null if the sequence is empty
    • iterate

      public ListIterator<T> iterate()
      Description copied from interface: GroundedValue
      Get an iterator over all the items in the sequence. This differs from the superclass method in not allowing an exception, either during this method call, or in the subsequent processing of the returned iterator.
      Specified by:
      iterate in interface GroundedValue
      Specified by:
      iterate in interface Sequence
      Returns:
      an iterator (meaning a Saxon SequenceIterator rather than a Java Iterator) over all the items in this Sequence.
    • iterator

      public Iterator<T> iterator()
      Specified by:
      iterator in interface Iterable<T extends Item>
    • itemAt

      public T itemAt(int n)
      Get the n'th item in the value, counting from 0
      Specified by:
      itemAt in interface GroundedValue
      Parameters:
      n - the index of the required item, with 0 representing the first item in the sequence
      Returns:
      the n'th item if it exists, or null otherwise
    • subsequence

      public ZeroOrMore<T> subsequence(int start, int length)
      Get a subsequence of the value
      Specified by:
      subsequence in interface GroundedValue
      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 size of the value (the number of items)
      Specified by:
      getLength in interface GroundedValue
      Returns:
      the number of items in the sequence
    • effectiveBooleanValue

      public boolean effectiveBooleanValue() throws XPathException
      Get the effective boolean value of this sequence
      Specified by:
      effectiveBooleanValue in interface GroundedValue
      Returns:
      the effective boolean value
      Throws:
      XPathException - if the sequence has no effective boolean value (for example a sequence of two integers)
    • getStringValue

      public String getStringValue() throws XPathException
      Get the string value of this sequence. The string value of an item is the result of applying the string() function. The string value of a sequence is the space-separated result of applying the string-join() function using a single space as the separator
      Specified by:
      getStringValue in interface GroundedValue
      Returns:
      the string value of the sequence.
      Throws:
      XPathException - if the sequence contains items that have no string value (for example, function items)
    • getStringValueCS

      public CharSequence getStringValueCS() throws XPathException
      Get the string value of this sequence. The string value of an item is the result of applying the string() function. The string value of a sequence is the space-separated result of applying the string-join() function using a single space as the separator
      Specified by:
      getStringValueCS in interface GroundedValue
      Returns:
      the string value of the sequence.
      Throws:
      XPathException - if the sequence contains items that have no string value (for example, function items)
    • reduce

      public GroundedValue reduce()
      Reduce the sequence to its simplest form. If the value is an empty sequence, the result will be EmptySequence.getInstance(). If the value is a single atomic value, the result will be an instance of AtomicValue. If the value is a single item of any other kind, the result will be an instance of One. Otherwise, the result will typically be unchanged.
      Specified by:
      reduce in interface GroundedValue
      Returns:
      the simplified sequence