Package net.sf.saxon.ma.arrays

Class ArrayItem

java.lang.Object
net.sf.saxon.ma.arrays.ArrayItem
All Implemented Interfaces:
Callable, FunctionItem, GroundedValue, Item, Sequence
Direct Known Subclasses:
AbstractArrayItem
public abstract class ArrayItem extends Object implements FunctionItem
Interface supported by different implementations of an XDM array item.

Saxon uses two main implementations of this interface: SimpleArrayItem, which is a wrapper over a Java List (which is assumed immutable), and ImmutableArrayItem, which is a wrapper over a Saxon ZenoChain, permitting efficient append and prepend operations without copying the entire content. Many of the expressions and functions that create arrays use a learning strategy to decide which implementation to use: if a significant number of SimpleArrayItem instances are subsequently converted to an ImmutableArrayItem, then future evaluations of the same expression will produce an ImmutableArrayItem directly.

  • Constructor Details

    • ArrayItem

      public ArrayItem()

  • Method Details

    • isArray

      public final boolean isArray()
      Ask whether this function item is an array
      Specified by:
      isArray in interface FunctionItem
      Returns:
      true if this function item is an array, otherwise false

    • isMap

      public final boolean isMap()
      Ask whether this function item is a map
      Specified by:
      isMap in interface FunctionItem
      Returns:
      false (it is not a map)

    • get

      public abstract GroundedValue get(int index)
      Get a member of the array
      Parameters:
      index - the position of the member to retrieve (zero-based)
      Returns:
      the value at the given position.
      Throws:
      IndexOutOfBoundsException - if the index is out of range

    • put

      public abstract ArrayItem put(int index, GroundedValue newValue)
      Replace a member of the array
      Parameters:
      index - the position of the member to replace (zero-based)
      newValue - the replacement value
      Returns:
      the value at the given position.
      Throws:
      IndexOutOfBoundsException - if the index is out of range

    • arrayLength

      public abstract int arrayLength()
      Get the number of members in the array

      Note: the method always returns 1, because an array is an item

      Returns:
      the number of members in this array.

    • isEmpty

      public boolean isEmpty()
      Ask whether the array is empty
      Returns:
      true if and only if the size of the array is zero

    • members

      public abstract Iterable<GroundedValue> members()
      Get the list of all members of the array
      Returns:
      an iterator over the members of the array

    • parcels

      public SequenceIterator parcels()
      Get an iterator over the members of the array, each represented as a Parcel
      Returns:
      an SequenceIterator over the members of the array, represented as parcels

    • append

      public abstract ArrayItem append(GroundedValue newMember)
      Add a member to this array
      Parameters:
      newMember - the member to be added
      Returns:
      the new array, comprising the members of this array and then one additional member.

    • concat

      public abstract ArrayItem concat(ArrayItem other)
      Concatenate this array with another
      Parameters:
      other - the second array
      Returns:
      the concatenation of the two arrays; that is, an array containing first the members of this array, and then the members of the other array

    • remove

      public abstract ArrayItem remove(int index)
      Remove a member from the array
      Parameters:
      index - the position of the member to be removed (zero-based)
      Returns:
      a new array in which the requested member has been removed.
      Throws:
      IndexOutOfBoundsException - if index is out of range

    • removeSeveral

      public abstract ArrayItem removeSeveral(IntSet positions)
      Remove zero or more members from the array
      Parameters:
      positions - the positions of the members to be removed (zero-based). A value that is out of range is ignored.
      Returns:
      a new array in which the requested member has been removed
      Throws:
      IndexOutOfBoundsException - if any of the positions is out of range

    • subArray

      public abstract ArrayItem subArray(int start, int end)
      Get a sub-array given a start and end position
      Parameters:
      start - the start position (zero based)
      end - the end position (the position of the first item not to be returned) (zero based)
      Returns:
      a new array item containing the sub-array
      Throws:
      IndexOutOfBoundsException - if start, or start+end, is out of range

    • insert

      public abstract ArrayItem insert(int position, GroundedValue member)
      Insert a new member into an array
      Parameters:
      position - the 0-based position that the new item will assume
      member - the new member to be inserted
      Returns:
      a new array item with the new member inserted
      Throws:
      IndexOutOfBoundsException - if position is out of range

    • getMemberType

      public abstract SequenceType getMemberType(TypeHierarchy th)
      Get the lowest common item type of the members of the array
      Parameters:
      th - the type hierarchy
      Returns:
      the most specific type to which all the members belong.

    • toShortString

      public String toShortString()
      Provide a short string showing the contents of the item, suitable for use in error messages
      Specified by:
      toShortString in interface FunctionItem
      Specified by:
      toShortString in interface GroundedValue
      Specified by:
      toShortString in interface Item
      Returns:
      a depiction of the item suitable for use in error messages

    • getGenre

      public final Genre getGenre()
      Get the genre of this item
      Specified by:
      getGenre in interface FunctionItem
      Specified by:
      getGenre in interface Item
      Returns:
      the genre: specifically, Genre.ARRAY.