com.saxonica.functions.map
Class SingletonMap

java.lang.Object
  com.saxonica.functions.map.SingletonMap

All Implemented Interfaces:

MapItem, PullEvent, FunctionItem<MapItem>, GroundedValue<MapItem>, Item<MapItem>, ValueRepresentation<MapItem>

public class SingletonMap
extends Object
implements MapItem, GroundedValue<MapItem>

A map containing a single entry

Field Summary

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Constructor Summary

SingletonMap(AtomicValue key, ValueRepresentation<? extends Item> value)
Construct the singleton map

Method Summary

FunctionItem	curry(ValueRepresentation<? extends Item>[] value) Curry a function by binding one or more (but not all) of its arguments
boolean	deepEquals(FunctionItem other, XPathContext context, GenericAtomicComparer comparer, int flags) Test whether this FunctionItem is deep-equal to another function item, under the rules of the deep-equal function
ValueRepresentation<? extends Item>	get(AtomicValue key, XPathContext context) Get an entry from the Map.
int	getArity() Get the arity of the function
StringCollator	getCollation() Get the collation of the map
String	getCollationName() Get the name of the collation of the map
FunctionItemType	getFunctionItemType(TypeHierarchy th) Get the item type of the function item
StructuredQName	getFunctionName() Get the name of the function, or null if it is anonymous
AtomicType	getKeyType(TypeHierarchy th) Get the lowest common item type of the keys in the map
int	getLength() Get the size of the value (the number of items)
String	getStringValue() Get the value of the item as a string.
CharSequence	getStringValueCS() Get the string value of the item as a CharSequence.
SequenceIterator<? extends AtomicValue>	getTypedValue() Get the typed value of the item.
SequenceType	getValueType(TypeHierarchy th) Get the lowest common sequence type of all the values in the map
SequenceIterator<? extends Item>	invoke(SequenceIterator<? extends Item>[] args, XPathContext context) Invoke the function
boolean	isEmpty() Ask whether the map is empty
MapItem	itemAt(int n) Get the n'th item in the value, counting from 0
UnfailingIterator<AtomicValue>	keys() Get the set of all key values in the map.
MapItem	remove(AtomicValue key, XPathContext context) Remove an entry from the map
void	setCollation(String collationName, StringCollator collation) Set the collation of the map
int	size() Get the size of the map
GroundedValue<MapItem>	subsequence(int start, int length) Get a subsequence of the value

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SingletonMap

public SingletonMap(AtomicValue key,
                    ValueRepresentation<? extends Item> value)

Construct the singleton map

Parameters:

key - the key

value - the value

Method Detail

getLength

public int getLength()

Get the size of the value (the number of items)

Specified by:

getLength in interface GroundedValue<MapItem>

Returns:

the number of items in the sequence

setCollation

public void setCollation(String collationName,
                         StringCollator collation)

Set the collation of the map

Parameters:

collationName - the name of the collation to be used by this map

collation - the corresponding collation object

getCollation

public StringCollator getCollation()

Get the collation of the map

Specified by:

getCollation in interface MapItem

Returns:

the collation of the map

getCollationName

public String getCollationName()

Get the name of the collation of the map

Specified by:

getCollationName in interface MapItem

Returns:

the collation name

get

public ValueRepresentation<? extends Item> get(AtomicValue key,
                                               XPathContext context)
                                        throws XPathException

Get an entry from the Map. Return null if there is no matching entry.

Specified by:

get in interface MapItem

Parameters:

key - the value of the key

context - the XPath dynamic evaluation context

Returns:

the value associated with the given key, or null if the key is not present in the map

Throws:

XPathException - if a dynamic error occurs

remove

public MapItem remove(AtomicValue key,
                      XPathContext context)
               throws XPathException

Remove an entry from the map

Specified by:

remove in interface MapItem

Parameters:

key - the key of the entry to be removed

context - the XPath dynamic context

Returns:

a new map in which the requested entry has been removed; or this map unchanged if the specified key was not present

Throws:

XPathException - if a dynamic error occurs

size

public int size()

Get the size of the map

Specified by:

size in interface MapItem

Returns:

the number of entries in the map (always one for this implementation)

isEmpty

public boolean isEmpty()

Ask whether the map is empty

Specified by:

isEmpty in interface MapItem

Returns:

true if and only if the size of the map is zero

keys

public UnfailingIterator<AtomicValue> keys()

Get the set of all key values in the map.

Specified by:

keys in interface MapItem

Returns:

a set containing all the key values present in the map.

getKeyType

public AtomicType getKeyType(TypeHierarchy th)

Get the lowest common item type of the keys in the map

Specified by:

getKeyType in interface MapItem

Parameters:

th - the type hierarchy

Returns:

the most specific type to which all the keys belong. If the map is empty, return AnyAtomicType by convention

getValueType

public SequenceType getValueType(TypeHierarchy th)

Get the lowest common sequence type of all the values in the map

Specified by:

getValueType in interface MapItem

Parameters:

th - the type hierarchy

Returns:

the most specific sequence type to which all the values belong. If the map is empty, return ANY_SEQUENCE by convention

getFunctionItemType

public FunctionItemType getFunctionItemType(TypeHierarchy th)

Get the item type of the function item

Specified by:

getFunctionItemType in interface FunctionItem<MapItem>

Parameters:

th - the type hierarchy cache. If null is supplied, the resulting item type may be less precise.

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<MapItem>

Returns:

the function name, or null for an anonymous inline function

getArity

public int getArity()

Get the arity of the function

Specified by:

getArity in interface FunctionItem<MapItem>

Returns:

the number of arguments in the function signature

invoke

public SequenceIterator<? extends Item> invoke(SequenceIterator<? extends Item>[] args,
                                               XPathContext context)
                                        throws XPathException

Invoke the function

Specified by:

invoke in interface FunctionItem<MapItem>

Parameters:

args - the actual arguments to be supplied

context - the XPath dynamic evaluation context

Returns:

the result of invoking the function

Throws:

XPathException - if a dynamic error occurs

curry

public FunctionItem curry(ValueRepresentation<? extends Item>[] value)
                   throws XPathException

Curry a function by binding one or more (but not all) of its arguments

Specified by:

curry in interface FunctionItem<MapItem>

Parameters:

value - the values to which the arguments are to be bound

Returns:

a new function item in which the specified arguments of the original function is bound to a value

Throws:

XPathException - if any dynamic error occurs

getStringValue

public String getStringValue()

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.

If the calling code can handle any CharSequence, the method getStringValueCS() should be used. If the caller requires a string, this method is preferred.

Specified by:

getStringValue in interface Item<MapItem>

Specified by:

getStringValue in interface ValueRepresentation<MapItem>

Returns:

the string value of the item

Throws:

UnsupportedOperationException - 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

See Also:

getStringValueCS()

getStringValueCS

public CharSequence getStringValueCS()

Get the string value of the item as a CharSequence. This is in some cases more efficient than the version of the method that returns a String. The method satisfies the rule that X.getStringValueCS().toString() returns a string that is equal to X.getStringValue().

Note that two CharSequence values of different types should not be compared using equals(), and for the same reason they should not be used as a key in a hash table.

If the calling code can handle any CharSequence, this method should be used. If the caller requires a string, the getStringValue() method is preferred.

Specified by:

getStringValueCS in interface Item<MapItem>

Specified by:

getStringValueCS in interface ValueRepresentation<MapItem>

Returns:

the string value of the item

Throws:

UnsupportedOperationException - 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

See Also:

getStringValue()

getTypedValue

public SequenceIterator<? extends AtomicValue> 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.

Specified by:

getTypedValue in interface Item<MapItem>

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,
                          GenericAtomicComparer 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<MapItem>

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

itemAt

public MapItem itemAt(int n)

Description copied from interface: GroundedValue

Get the n'th item in the value, counting from 0

Specified by:

itemAt in interface GroundedValue<MapItem>

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 GroundedValue<MapItem> subsequence(int start,
                                          int length)

Description copied from interface: GroundedValue

Get a subsequence of the value

Specified by:

subsequence in interface GroundedValue<MapItem>

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