Package net.sf.saxon.value

Class SequenceSlice<T extends Item<?>>

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

    • Constructor Detail

      • SequenceSlice

        public SequenceSlice​(List<T> value,
                     int offset,
                     int length)
        Construct an sequence from a slice of a list of items. Note, the list of items is used as is, which means the caller must not subsequently change its contents.
        Parameters:
        value - the list of items
        offset - the zero-based position of the first item to be included in the sequence
        length - the number of items to be included in the sequence; if this exceeds the number of items available for inclusion, include all items up to the end of the sequence
        Throws:
        IndexOutOfBoundsException - if offset < 0 or length < 0 or offset + length < value.size()

    • Method Detail

      • getStringValue

        public String getStringValue()
                      throws XPathException
        Description copied from interface: GroundedValue
        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<T extends Item<?>>
        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
        Description copied from interface: GroundedValue
        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<T extends Item<?>>
        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<T extends Item<?>>
        Specified by:
        head in interface Sequence<T extends Item<?>>
        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<T extends Item<?>>
        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<T extends Item<?>>
        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<T> iterate()
        Return an iterator over this sequence.
        Specified by:
        iterate in interface GroundedValue<T extends Item<?>>
        Specified by:
        iterate in interface Sequence<T extends Item<?>>
        Returns:
        the required SequenceIterator, positioned at the start of the sequence

      • subsequence

        public GroundedValue<T> subsequence​(int start,
                                    int length)
        Get a subsequence of the value
        Specified by:
        subsequence in interface GroundedValue<T extends Item<?>>
        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

      • reduce

        public GroundedValue<T> 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<T extends Item<?>>
        Returns:
        the simplified sequence

      • asIterable

        public Iterable<T> asIterable()
        Get the contents of this value in the form of a Java Iterable, so that it can be used in a for-each expression
        Specified by:
        asIterable in interface GroundedValue<T extends Item<?>>
        Specified by:
        asIterable in interface Sequence<T extends Item<?>>
        Returns:
        an Iterable containing the same sequence of items