com.saxonica.functions.map

Class RangeKey

java.lang.Object

com.saxonica.functions.map.RangeKey

All Implemented Interfaces:

MapItem, PullEvent, Callable, FunctionItem, GroundedValue, Item, Sequence

public class RangeKey
extends Object
implements MapItem

This class implements an XPath map item as a view of an XSLT key index. It is possible to specify a minimum and maximum key value to be included in the map, and keys are returned in sorted order.

At present range keys are only available for string-valued keys using the Unicode codepoint collating sequence.

Constructor Summary

Constructors

Constructor and Description
RangeKey(String min, String max, TreeMap<String,List<NodeInfo>> index)

Method Summary

Methods

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] args) Invoke the function
boolean	deepEquals(FunctionItem other, XPathContext context, AtomicComparer comparer, int flags) Test whether this FunctionItem is deep-equal to another function item, under the rules of the deep-equal function
boolean	effectiveBooleanValue() Get the effective boolean value of this sequence
Sequence	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
MapType	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.
SequenceType	getValueType(TypeHierarchy th) Get the lowest common sequence type of all the values in the map
Item	head() Get the first item in the sequence.
boolean	isEmpty() Ask whether the map is empty
Item	itemAt(int n) Get the n'th item in the value, counting from 0
SequenceIterator	iterate() Get an iterator over all the items in the sequence
UnfailingIterator<StringValue>	keys() Get the set of all key values in the map.
GroundedValue	reduce() Reduce the sequence to its simplest form.
MapItem	remove(AtomicValue key, XPathContext context) Remove an entry from the map
int	size() Get the size of the map
GroundedValue	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

RangeKey

public RangeKey(String min,
        String max,
        TreeMap<String,List<NodeInfo>> index)
         throws XPathException

Throws:

XPathException

Method Detail

getCollationName

public String getCollationName()

Get the name of the collation of the map

Specified by:

getCollationName in interface MapItem

Returns:

the collation name

getCollation

public StringCollator getCollation()

Get the collation of the map

Specified by:

getCollation in interface MapItem

Returns:

the collation of the map

get

public Sequence get(AtomicValue key,
           XPathContext context)
             throws XPathException

Get an entry from the Map

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

size

public int size()

Get the size of the map

Specified by:

size in interface MapItem

Returns:

the number of keys/entries present in this map

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<StringValue> 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.

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

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 MapType getFunctionItemType(TypeHierarchy th)

Get the item type of the function item

Specified by:

getFunctionItemType in interface FunctionItem

Parameters:

th - the type hierarchy cache

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

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

call

public Sequence call(XPathContext context,
            Sequence[] args)
              throws XPathException

Invoke the function

Specified by:

call in interface Callable

Specified by:

call in interface FunctionItem

Parameters:

context - the XPath dynamic evaluation context

args - the actual arguments to be supplied

Returns:

the result of invoking the function

Throws:

XPathException - if a dynamic error occurs within the function

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

itemAt

public Item itemAt(int n)

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

Specified by:

itemAt in interface GroundedValue

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 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

getLength

public int getLength()

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

Specified by:

getLength in interface GroundedValue

Returns:

the number of items in the sequence

effectiveBooleanValue

public boolean effectiveBooleanValue()
                              throws XPathException

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)

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 SingletonItem. Otherwise, the result will typically be unchanged.

Specified by:

reduce in interface GroundedValue

Returns:

the simplified sequence

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 GroundedValue

Specified by:

getStringValue in interface Item

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 GroundedValue

Specified by:

getStringValueCS in interface Item

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()

head

public Item head()
          throws XPathException

Get the first item in the sequence.

Specified by:

head in interface Sequence

Returns:

the first item in the sequence if there is one, or null if the sequence is empty

Throws:

XPathException - in the situation where the sequence is evaluated lazily, and evaluation of the first item causes a dynamic error.

iterate

public SequenceIterator iterate()
                         throws XPathException

Get an iterator over all the items in the sequence

Specified by:

iterate in interface Sequence

Returns:

an iterator over all the items

Throws:

XPathException - in the situation where the sequence is evaluated lazily, and constructing an iterator over the items causes a dynamic error.