Package net.sf.saxon.om

Class ZeroOrMore<T extends Item>

  • All Implemented Interfaces:
    java.lang.Iterable<T>, GroundedValue, Sequence
    Direct Known Subclasses:
    OneOrMore
    public class ZeroOrMore<T extends Item>
extends java.lang.Object
implements GroundedValue, java.lang.Iterable<T>
    A sequence value implemented extensionally. That is, this class represents a sequence by allocating memory to each item in the sequence.

    • Constructor Detail

      • ZeroOrMore

        public ZeroOrMore​(java.util.List<T> list)
        Construct a SequenceExtent from a List. The members of the list must all be Items
        Parameters:
        list - the list of items to be included in the sequence

    • Method Detail

      • getValue

        protected java.util.List<T> getValue()

      • getUnicodeStringValue

        public UnicodeString getUnicodeStringValue()
                                    throws XPathException
        Description copied from interface: GroundedValue
        Get the string value of this sequence, as an instance of UnicodeString. The string value of an item is the result of applying the XPath 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

        The result of this method is always equivalent to the result of the GroundedValue.getStringValue() method. Use this method in preference either (a) if you need to use the value in a context where a UnicodeString is required, or (b) if the underlying value is held as a UnicodeString, or in a form that is readily converted to a UnicodeString. This is typically the case (i) when the value is a text or element node in a TinyTree, and (ii) when the value is a StringItem: that is, an atomic value of type xs:string.

        Specified by:
        getUnicodeStringValue 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)

      • getStringValue

        public java.lang.String getStringValue()
                                throws XPathException
        Description copied from interface: GroundedValue
        Get the string value of this sequence, as an instance of String. The string value of an item is the result of applying the XPath 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.

        The result of this method is always equivalent to the result of the GroundedValue.getUnicodeStringValue() method. Use this method in preference either (a) if you need to use the value in a context where a String is required, or (b) if the underlying value is held as a String, or in a form that is readily converted to a String. This is typically the case (i) when the value is an attribute node in a TinyTree, or (ii) any kind of node in a third-party tree model such as DOM.

        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)

      • head

        public T head()
        Get the first item in the sequence.
        Specified by:
        head in interface GroundedValue
        Specified by:
        head in interface Sequence
        Returns:
        the first item in the sequence if there is one, or null if the sequence is empty

      • getLength

        public int getLength()
        Get the number of items in the sequence
        Specified by:
        getLength in interface GroundedValue
        Returns:
        the number of items in the sequence

      • getCardinality

        public int getCardinality()
        Determine the cardinality
        Returns:
        the cardinality of the sequence, using the constants defined in net.sf.saxon.value.Cardinality
        See Also:
        Cardinality

      • itemAt

        public T itemAt​(int n)
        Get the n'th item in the sequence (starting with 0 as the first item)
        Specified by:
        itemAt in interface GroundedValue
        Parameters:
        n - the position of the required item
        Returns:
        the n'th item in the sequence, or null if the position is out of range

      • iterate

        public ListIterator.Of<T> iterate()
        Return an iterator over this sequence.
        Specified by:
        iterate in interface GroundedValue
        Specified by:
        iterate in interface Sequence
        Returns:
        the required SequenceIterator, positioned at the start of the sequence

      • reverseIterate

        public SequenceIterator reverseIterate()
        Return an enumeration of this sequence in reverse order (used for reverse axes)
        Returns:
        an AxisIterator that processes the items in reverse order

      • effectiveBooleanValue

        public boolean effectiveBooleanValue()
                              throws XPathException
        Get the effective boolean value
        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)

      • subsequence

        public GroundedValue 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. If min is

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • 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

      • iterator

        public java.util.Iterator<T> iterator()
        Get an iterator (a Java Iterator) over the items in this sequence.
        Specified by:
        iterator in interface java.lang.Iterable<T extends Item>
        Returns:
        an iterator over the items in this sequence.