Package net.sf.saxon.ma.map

Class MapItem

java.lang.Object
net.sf.saxon.ma.map.MapItem
All Implemented Interfaces:
Callable, FunctionItem, GroundedValue, Item, Sequence
Direct Known Subclasses:
DelegatingMapItem, DictionaryMap, HashTrieMap, RangeKey, SingleEntryMap
public abstract class MapItem extends Object implements FunctionItem
Interface supported by different implementations of an XDM map item

  • Constructor Details

    • MapItem

      public MapItem()

  • Method Details

    • get

      public abstract GroundedValue get(AtomicValue key)
      Get an entry from the Map
      Parameters:
      key - the value of the key
      Returns:
      the value associated with the given key, or null if the key is not present in the map.

    • size

      public abstract int size()
      Get the size of the map
      Returns:
      the number of keys/entries present in this map

    • isEmpty

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

    • keys

      public abstract AtomicIterator keys()
      Get the set of all key values in the map.
      Returns:
      a set containing all the key values present in the map, in unpredictable order

    • keyValuePairs

      public abstract Iterable<KeyValuePair> keyValuePairs()
      Get the set of all key-value pairs in the map
      Returns:
      an iterable containing all the key-value pairs

    • entries

      public SequenceIterator entries()
      Get an iterator over the entries in the map, each represented as a singleton map (representing one key-value pair)
      Returns:
      a SequenceIterator over the entries in the map, represented as single-entry maps

    • addEntry

      public abstract MapItem addEntry(AtomicValue key, GroundedValue value)
      Create a new map containing the existing entries in the map plus an additional entry, without modifying the original. If there is already an entry with the specified key, this entry is replaced by the new entry.
      Parameters:
      key - the key of the new entry
      value - the value associated with the new entry
      Returns:
      the new map containing the additional entry

    • remove

      public abstract MapItem remove(AtomicValue key)
      Remove an entry from the map
      Parameters:
      key - the key of the entry to be removed
      Returns:
      a new map in which the requested entry has been removed; or this map unchanged if the specified key was not present

    • conforms

      public abstract boolean conforms(PlainType keyType, SequenceType valueType, TypeHierarchy th)
      Ask whether the map conforms to a given map type
      Parameters:
      keyType - the required keyType
      valueType - the required valueType
      th - the type hierarchy cache for the configuration
      Returns:
      true if the map conforms to the required type

    • getItemType

      public abstract ItemType getItemType(TypeHierarchy th)
      Get the type of the map. This method is used largely for diagnostics, to report the type of a map when it differs from the required type.
      Parameters:
      th - the type hierarchy cache
      Returns:
      the type of this map

    • getKeyUType

      public abstract UType getKeyUType()
      Get the lowest common item type of the keys in the map
      Returns:
      the most specific type to which all the keys belong. If the map is empty, return UType.VOID

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

    • isArray

      public boolean isArray()
      Ask whether this function item is an array
      Specified by:
      isArray in interface FunctionItem
      Returns:
      false (it is not an array)

    • isMap

      public boolean isMap()
      Ask whether this function item is a map
      Specified by:
      isMap in interface FunctionItem
      Returns:
      true (it is a map)

    • getAnnotations

      public AnnotationList getAnnotations()
      Get the function annotations (as defined in XQuery). Returns an empty list if there are no function annotations.
      Specified by:
      getAnnotations in interface FunctionItem
      Returns:
      the function annotations

    • atomize

      public AtomicSequence atomize() throws XPathException
      Atomize the item.
      Specified by:
      atomize in interface Item
      Returns:
      the result of atomization
      Throws:
      XPathException - if atomization is not allowed for this kind of item

    • isKnownToConform

      public static boolean isKnownToConform(Sequence value, ItemType itemType)
      Ask whether all the items in a sequence are known to conform to a given item type
      Parameters:
      value - the sequence
      itemType - the given item type
      Returns:
      true if all the items conform; false if not, or if the information cannot be efficiently determined

    • getItemTypeOfSequence

      public static ItemType getItemTypeOfSequence(Sequence val)
      Get an item type to which all the values in a sequence are known to conform
      Parameters:
      val - the sequence
      Returns:
      the type of the first item in the sequence, provided that all subsequent values in the sequence are known to conform to this type; otherwise item().

    • getOperandRoles

      public OperandRole[] getOperandRoles()
      Get the roles of the arguments, for the purposes of streaming
      Specified by:
      getOperandRoles in interface FunctionItem
      Returns:
      an array of OperandRole objects, one for each argument

    • getFunctionItemType

      public FunctionItemType getFunctionItemType()
      Get the item type of this item as a function item. Note that this returns the generic function type for maps, not a type related to this specific map.
      Specified by:
      getFunctionItemType in interface FunctionItem
      Returns:
      the function item's type

    • getFunctionName

      public StructuredQName getFunctionName()
      Get the name of the function, or null if it is anonymous
      Specified by:
      getFunctionName in interface FunctionItem
      Returns:
      the function name, or null for an anonymous inline function

    • getDescription

      public String getDescription()
      Get a description of this function for use in error messages. For named functions, the description is the function name (as a lexical QName). For others, it might be, for example, "inline function", or "partially-applied ends-with function".
      Specified by:
      getDescription in interface FunctionItem
      Returns:
      a description of the function for use in error messages

    • getArity

      public int getArity()
      Get the arity of the function
      Specified by:
      getArity in interface FunctionItem
      Returns:
      the number of arguments in the function signature

    • makeNewContext

      public XPathContext makeNewContext(XPathContext callingContext, ContextOriginator originator)
      Prepare an XPathContext object for evaluating the function
      Specified by:
      makeNewContext in interface FunctionItem
      Parameters:
      callingContext - the XPathContext of the function calling expression
      originator - not used
      Returns:
      a suitable context for evaluating the function (which may or may not be the same as the caller's context)

    • call

      public Sequence call(XPathContext context, Sequence[] args) throws XPathException
      Invoke the function
      Specified by:
      call in interface Callable
      Parameters:
      context - the XPath dynamic evaluation context
      args - the actual arguments to be supplied
      Returns:
      the result of invoking the function
      Throws:
      XPathException - if an error occurs evaluating the supplied argument

    • getUnicodeStringValue

      public UnicodeString getUnicodeStringValue()
      Get the value of the item as a string. For nodes, this is the string value of the node as defined in the XPath 2.0 data model, except that all nodes are treated as being untyped: it is not an error to get the string value of a node with a complex type. For atomic values, the method returns the result of casting the atomic value to a string.
      Specified by:
      getUnicodeStringValue in interface GroundedValue
      Specified by:
      getUnicodeStringValue in interface Item
      Returns:
      the string value of the item
      Throws:
      UncheckedXPathException - if the item is a function item (an unchecked exception is used here to avoid introducing exception handling to a large number of paths where it is not needed)
      Since:
      8.4

    • getTypedValue

      public SequenceIterator getTypedValue() throws XPathException
      Get the typed value of the item.

      For a node, this is the typed value as defined in the XPath 2.0 data model. Since a node may have a list-valued data type, the typed value is in general a sequence, and it is returned in the form of a SequenceIterator.

      If the node has not been validated against a schema, the typed value will be the same as the string value, either as an instance of xs:string or as an instance of xs:untypedAtomic, depending on the node kind.

      For an atomic value, this method returns an iterator over a singleton sequence containing the atomic value itself.

      Returns:
      an iterator over the items in the typed value of the node or atomic value. The items returned by this iterator will always be atomic values.
      Throws:
      XPathException - where no typed value is available, for example in the case of an element with complex content
      Since:
      8.4

    • deepEquals

      public boolean deepEquals(FunctionItem other, XPathContext context, AtomicComparer comparer, int flags) throws XPathException
      Test whether this FunctionItem is deep-equal to another function item, under the rules of the deep-equal function
      Specified by:
      deepEquals in interface FunctionItem
      Parameters:
      other - the other function item
      context - the dynamic evaluation context
      comparer - the object to perform the comparison
      flags - options for how the comparison is performed
      Returns:
      true if the two function items are deep-equal
      Throws:
      XPathException - if the comparison cannot be performed

    • deepEqual40

      public boolean deepEqual40(FunctionItem other, XPathContext context, DeepEqual.DeepEqualOptions options) throws XPathException
      Specified by:
      deepEqual40 in interface FunctionItem
      Throws:
      XPathException

    • itemAt

      public MapItem itemAt(int n)
      Description copied from interface: Item
      Get the n'th item in the value, counting from 0
      Specified by:
      itemAt in interface GroundedValue
      Specified by:
      itemAt in interface Item
      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

    • effectiveBooleanValue

      public boolean effectiveBooleanValue() throws XPathException
      Description copied from interface: GroundedValue
      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)

    • mapToString

      public static String mapToString(MapItem map)
      Returns a string representation of the map.
      Parameters:
      map - the input map
      Returns:
      a string representation of the input map (using syntax resembling that of an XPath 3.1 map constructor).

    • export

      public void export(ExpressionPresenter out) throws XPathException
      Export information about this function item to the export() or explain() output
      Specified by:
      export in interface FunctionItem
      Parameters:
      out - the destination for the information
      Throws:
      XPathException - if things go wrong

    • isTrustedResultType

      public boolean isTrustedResultType()
      Description copied from interface: FunctionItem
      Ask if the function can be trusted to return a result of the correct type
      Specified by:
      isTrustedResultType in interface FunctionItem
      Returns:
      true if the implementation can be trusted