org.exist.xquery.value
Class AtomicValue

java.lang.Object
  org.exist.xquery.value.AtomicValue

All Implemented Interfaces:

Comparable, Indexable, Item, Sequence

Direct Known Subclasses:

AnyURIValue, BinaryValue, BooleanValue, ComputableValue, FunctionReference, JavaObjectValue, QNameValue, StringValue, UntypedAtomicValue

public abstract class AtomicValue
extends Object
implements Item, Sequence, Indexable

Represents an atomic value. All simple values that are not nodes extend AtomicValue. As every single item is also a sequence, this class implements both: Item and Sequence.

Author:

wolf

Field Summary

static AtomicValue

EMPTY_VALUE An empty atomic value

Fields inherited from interface org.exist.xquery.value.Sequence

EMPTY_SEQUENCE

Constructor Summary

AtomicValue()

Method Summary

void	add(Item item) Add an item to the current sequence.
void	addAll(Sequence other) Add all items of the other sequence to this item.
AtomicValue	atomize()
void	clearContext(int contextId) For every item in the sequence, clear any context-dependant information that is stored during query processing.
abstract int	compareTo(Collator collator, AtomicValue other)
abstract boolean	compareTo(Collator collator, int operator, AtomicValue other)
int	compareTo(Object other)
boolean	contains(Collator collator, AtomicValue other) Compares this atomic value to another.
int	conversionPreference(Class javaClass) Returns a preference indicator, indicating the preference of a value to be converted into the given Java class.
abstract AtomicValue	convertTo(int requiredType) Convert this item into an atomic value, whose type corresponds to the specified target type.
void	copyTo(DBBroker broker, DocumentBuilderReceiver receiver)
void	dump(ExpressionDumper dumper) Dump a string representation of this value to the given ExpressionDumper.
abstract boolean	effectiveBooleanValue() Get the effective boolean value of this sequence.
boolean	endsWith(Collator collator, AtomicValue other) Compares this atomic value to another.
int	getCardinality() Returns the cardinality of this sequence.
Iterator	getCollectionIterator() Return an iterator on all collections referenced by documents contained in this sequence..
DocumentSet	getDocumentSet() Returns the set of documents from which the node items in this sequence have been selected.
int	getItemCount() Returns the number of items contained in the sequence.
int	getItemType() Return the primary type to which all items in this sequence belong.
int	getState()
abstract String	getStringValue() Return the string value of this item (see the definition of string value in XPath).
int	getType() Returns the type of the Indexable as one of the constants defined in Type.
boolean	hasChanged(int previousState)
boolean	hasMany() Returns whether the sequence more than one item or not.
boolean	hasOne() Returns whether the sequence has just one item or not.
boolean	isCacheable()
boolean	isCached() Returns true if the sequence is the result of a previous operation and has been cached.
boolean	isEmpty() Returns whether the sequence is empty or not.
boolean	isPersistentSet()
Item	itemAt(int pos) Returns the item located at the specified position within this sequence.
SequenceIterator	iterate() Returns an iterator over all items in the sequence.
abstract AtomicValue	max(Collator collator, AtomicValue other)
abstract AtomicValue	min(Collator collator, AtomicValue other)
void	nodeMoved(NodeId oldNodeId, StoredNode newNode) Nodes may implement this method to be informed of storage address and node id changes after updates.
AtomicValue	promote(AtomicValue otherValue)
void	removeDuplicates() Explicitely remove all duplicate nodes from this sequence.
byte[]	serializeValue(int offset) Serialize the value to an array of bytes for the persistant storage.
void	setIsCached(boolean cached) Indicates that the sequence is the result of a previous operation and has not been recomputed.
void	setSelfAsContext(int contextId)
boolean	startsWith(Collator collator, AtomicValue other) Compares this atomic value to another.
Object	toJavaObject(Class target) Convert the value into an instance of the specified Java class.
MemoryNodeSet	toMemNodeSet() Convert the sequence into an in-memory node set.
NodeSet	toNodeSet() Convert the sequence into a NodeSet.
void	toSAX(DBBroker broker, ContentHandler handler, Properties properties)
Sequence	toSequence() Convert this item into a sequence, containing only the item.
String	toString()
SequenceIterator	unorderedIterator() Returns an iterator over all items in the sequence.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY_VALUE

public static final AtomicValue EMPTY_VALUE

An empty atomic value

Constructor Detail

AtomicValue

public AtomicValue()

Method Detail

getType

public int getType()

Description copied from interface: Indexable

Returns the type of the Indexable as one of the constants defined in Type.

Specified by:

getType in interface Indexable

Specified by:

getType in interface Item

Returns:

Type of the Indexable

getStringValue

public abstract String getStringValue()
                               throws XPathException

Description copied from interface: Item

Return the string value of this item (see the definition of string value in XPath).

Specified by:

getStringValue in interface Item

Specified by:

getStringValue in interface Sequence

Throws:

XPathException

convertTo

public abstract AtomicValue convertTo(int requiredType)
                               throws XPathException

Description copied from interface: Item

Convert this item into an atomic value, whose type corresponds to the specified target type. requiredType should be one of the type constants defined in Type. An XPathException is thrown if the conversion is impossible.

Specified by:

convertTo in interface Item

Specified by:

convertTo in interface Sequence

Parameters:

requiredType - one of the type constants defined in class Type

Throws:

XPathException

compareTo

public abstract boolean compareTo(Collator collator,
                                  int operator,
                                  AtomicValue other)
                           throws XPathException

Throws:

XPathException

compareTo

public abstract int compareTo(Collator collator,
                              AtomicValue other)
                       throws XPathException

Throws:

XPathException

max

public abstract AtomicValue max(Collator collator,
                                AtomicValue other)
                         throws XPathException

Throws:

XPathException

min

public abstract AtomicValue min(Collator collator,
                                AtomicValue other)
                         throws XPathException

Throws:

XPathException

startsWith

public boolean startsWith(Collator collator,
                          AtomicValue other)
                   throws XPathException

Compares this atomic value to another. Returns true if the current value is of type string and its value starts with the string value of the other value.

Parameters:

collator - Collator used for string comparison.

other -

Throws:

XPathException - if this is not a string.

endsWith

public boolean endsWith(Collator collator,
                        AtomicValue other)
                 throws XPathException

Compares this atomic value to another. Returns true if the current value is of type string and its value ends with the string value of the other value.

Parameters:

collator - Collator used for string comparison.

other -

Throws:

XPathException - if this is not a string.

contains

public boolean contains(Collator collator,
                        AtomicValue other)
                 throws XPathException

Compares this atomic value to another. Returns true if the current value is of type string and its value contains the string value of the other value.

Parameters:

collator - Collator used for string comparison.

other -

Throws:

XPathException - if this is not a string.

getItemCount

public int getItemCount()

Description copied from interface: Sequence

Returns the number of items contained in the sequence. Call this method only when necessary, since it can be resource consuming.

Specified by:

getItemCount in interface Sequence

Returns:

The number of items in the sequence

getCardinality

public int getCardinality()

Description copied from interface: Sequence

Returns the cardinality of this sequence. The returned value is a combination of flags as defined in Cardinality.

Specified by:

getCardinality in interface Sequence

See Also:

Cardinality

removeDuplicates

public void removeDuplicates()

Description copied from interface: Sequence

Explicitely remove all duplicate nodes from this sequence.

Specified by:

removeDuplicates in interface Sequence

iterate

public SequenceIterator iterate()
                         throws XPathException

Description copied from interface: Sequence

Returns an iterator over all items in the sequence. The items are returned in document order where applicable.

Specified by:

iterate in interface Sequence

Throws:

XPathException - TODO

unorderedIterator

public SequenceIterator unorderedIterator()

Description copied from interface: Sequence

Returns an iterator over all items in the sequence. The returned items may - but need not - to be in document order.

Specified by:

unorderedIterator in interface Sequence

getItemType

public int getItemType()

Description copied from interface: Sequence

Return the primary type to which all items in this sequence belong. This is Type.NODE for node sets, Type.ITEM for other sequences with mixed items.

Specified by:

getItemType in interface Sequence

Returns:

the primary type of the items in this sequence.

itemAt

public Item itemAt(int pos)

Description copied from interface: Sequence

Returns the item located at the specified position within this sequence. Items are counted beginning at 0.

Specified by:

itemAt in interface Sequence

toSequence

public Sequence toSequence()

Description copied from interface: Item

Convert this item into a sequence, containing only the item.

Specified by:

toSequence in interface Item

toSAX

public void toSAX(DBBroker broker,
                  ContentHandler handler,
                  Properties properties)
           throws SAXException

Specified by:

toSAX in interface Item

Throws:

SAXException

copyTo

public void copyTo(DBBroker broker,
                   DocumentBuilderReceiver receiver)
            throws SAXException

Specified by:

copyTo in interface Item

Throws:

SAXException

isEmpty

public boolean isEmpty()

Description copied from interface: Sequence

Returns whether the sequence is empty or not.

Specified by:

isEmpty in interface Sequence

Returns:

true is the sequence is empty

hasOne

public boolean hasOne()

Description copied from interface: Sequence

Returns whether the sequence has just one item or not.

Specified by:

hasOne in interface Sequence

Returns:

true is the sequence has just one item

hasMany

public boolean hasMany()

Description copied from interface: Sequence

Returns whether the sequence more than one item or not.

Specified by:

hasMany in interface Sequence

Returns:

true is the sequence more than one item

add

public void add(Item item)
         throws XPathException

Description copied from interface: Sequence

Add an item to the current sequence. An XPathException may be thrown if the item's type is incompatible with this type of sequence (e.g. if the sequence is a node set). The sequence may or may not allow duplicate values.

Specified by:

add in interface Sequence

Throws:

XPathException

addAll

public void addAll(Sequence other)
            throws XPathException

Description copied from interface: Sequence

Add all items of the other sequence to this item. An XPathException may be thrown if the type of the items in the other sequence is incompatible with the primary type of this sequence.

Specified by:

addAll in interface Sequence

Throws:

XPathException

atomize

public AtomicValue atomize()
                    throws XPathException

Specified by:

atomize in interface Item

Throws:

XPathException

effectiveBooleanValue

public abstract boolean effectiveBooleanValue()
                                       throws XPathException

Description copied from interface: Sequence

Get the effective boolean value of this sequence. Will be false if the sequence is empty, true otherwise.

Specified by:

effectiveBooleanValue in interface Sequence

Throws:

XPathException

toNodeSet

public NodeSet toNodeSet()
                  throws XPathException

Description copied from interface: Sequence

Convert the sequence into a NodeSet. If the sequence contains items which are not nodes, an XPathException is thrown.

Specified by:

toNodeSet in interface Sequence

Throws:

XPathException - if the sequence contains items which are not nodes.

toMemNodeSet

public MemoryNodeSet toMemNodeSet()
                           throws XPathException

Description copied from interface: Sequence

Convert the sequence into an in-memory node set. If the sequence contains items which are not nodes, an XPathException is thrown. For persistent node sets, this method will return null. Call Sequence.isPersistentSet() to check if the sequence is a persistent node set.

Specified by:

toMemNodeSet in interface Sequence

Throws:

XPathException - if the sequence contains items which are not nodes or is a persistent node set

getDocumentSet

public DocumentSet getDocumentSet()

Description copied from interface: Sequence

Returns the set of documents from which the node items in this sequence have been selected. This is for internal use only.

Specified by:

getDocumentSet in interface Sequence

getCollectionIterator

public Iterator getCollectionIterator()

Description copied from interface: Sequence

Return an iterator on all collections referenced by documents contained in this sequence..

Specified by:

getCollectionIterator in interface Sequence

promote

public AtomicValue promote(AtomicValue otherValue)
                    throws XPathException

Throws:

XPathException

dump

public void dump(ExpressionDumper dumper)

Dump a string representation of this value to the given ExpressionDumper.

Parameters:

dumper -

conversionPreference

public int conversionPreference(Class javaClass)

Description copied from interface: Sequence

Returns a preference indicator, indicating the preference of a value to be converted into the given Java class. Low numbers mean that the value can be easily converted into the given class.

Specified by:

conversionPreference in interface Item

Specified by:

conversionPreference in interface Sequence

toJavaObject

public Object toJavaObject(Class target)
                    throws XPathException

Description copied from interface: Sequence

Convert the value into an instance of the specified Java class.

Specified by:

toJavaObject in interface Item

Specified by:

toJavaObject in interface Sequence

Throws:

XPathException

toString

public String toString()

Overrides:

toString in class Object

isCached

public boolean isCached()

Description copied from interface: Sequence

Returns true if the sequence is the result of a previous operation and has been cached.

Specified by:

isCached in interface Sequence

setIsCached

public void setIsCached(boolean cached)

Description copied from interface: Sequence

Indicates that the sequence is the result of a previous operation and has not been recomputed.

Specified by:

setIsCached in interface Sequence

clearContext

public void clearContext(int contextId)

Description copied from interface: Sequence

For every item in the sequence, clear any context-dependant information that is stored during query processing. This feature is used for node sets, which may store information about their context node.

Specified by:

clearContext in interface Sequence

setSelfAsContext

public void setSelfAsContext(int contextId)

Specified by:

setSelfAsContext in interface Sequence

isPersistentSet

public boolean isPersistentSet()

Specified by:

isPersistentSet in interface Sequence

nodeMoved

public void nodeMoved(NodeId oldNodeId,
                      StoredNode newNode)

Description copied from interface: Item

Nodes may implement this method to be informed of storage address and node id changes after updates.

Specified by:

nodeMoved in interface Item

Specified by:

nodeMoved in interface Sequence

See Also:

UpdateListener

serializeValue

public byte[] serializeValue(int offset)
                      throws EXistException

Description copied from interface: Indexable

Serialize the value to an array of bytes for the persistant storage. The returned byte array has the following format: (offset-1 free bytes, byte type, byte[] value)

Specified by:

serializeValue in interface Indexable

Parameters:

offset - starting index for writing in array data

Returns:

the size actually writen in the array argument

Throws:

EXistException

compareTo

public int compareTo(Object other)

Specified by:

compareTo in interface Comparable

getState

public int getState()

Specified by:

getState in interface Sequence

hasChanged

public boolean hasChanged(int previousState)

Specified by:

hasChanged in interface Sequence

isCacheable

public boolean isCacheable()

Specified by:

isCacheable in interface Sequence