org.exist.xquery.value
Class AbstractSequence

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

All Implemented Interfaces:

Sequence

Direct Known Subclasses:

AbstractNodeSet, EmptySequence, GroupedValueSequence, OrderedValueSequence, PreorderedValueSequence, ValueSequence

public abstract class AbstractSequence
extends Object
implements Sequence

An abstract implementation of Sequence with default implementations for some methods.

Field Summary

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

EMPTY_SEQUENCE

Method Summary

abstract 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.
void	clearContext(int contextId) For every item in the sequence, clear any context-dependant information that is stored during query processing.
int	conversionPreference(Class javaClass) Returns a preference indicator, indicating the preference of a value to be converted into the given Java class.
AtomicValue	convertTo(int requiredType) Try to convert the sequence into an atomic value.
boolean	effectiveBooleanValue() See 2.4.3 Effective Boolean Value
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.
abstract int	getItemCount() Returns the number of items contained in the sequence.
abstract int	getItemType() Return the primary type to which all items in this sequence belong.
int	getState()
String	getStringValue() Convert the sequence to a string.
boolean	hasChanged(int previousState)
boolean	hasMany() Returns whether the sequence more than one item or not.
abstract 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.
abstract boolean	isEmpty() Returns whether the sequence is empty or not.
boolean	isPersistentSet()
abstract Item	itemAt(int pos) Returns the item located at the specified position within this sequence.
abstract SequenceIterator	iterate() Returns an iterator over all items in the sequence.
void	nodeMoved(NodeId oldNodeId, StoredNode newNode) Node sets may implement this method to be informed of storage address and node id changes after updates.
void	setIsCached(boolean cached) Indicates that the sequence is the result of a previous operation and has not been recomputed.
void	setSelfAsContext(int contextId)
Object	toJavaObject(Class target) Convert the value into an instance of the specified Java class.
String	toString()
abstract 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

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

removeDuplicates, toMemNodeSet, toNodeSet

Method Detail

getItemType

public abstract 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.

iterate

public abstract 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 abstract SequenceIterator unorderedIterator()
                                            throws XPathException

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

Throws:

XPathException

getItemCount

public abstract 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

convertTo

public AtomicValue convertTo(int requiredType)
                      throws XPathException

Description copied from interface: Sequence

Try to convert the sequence into an atomic value. The target type should be specified by using one of the constants defined in class Type. An XPathException is thrown if the conversion is impossible.

Specified by:

convertTo in interface Sequence

Parameters:

requiredType - one of the type constants defined in class Type

Throws:

XPathException

isEmpty

public abstract 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 abstract 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

getStringValue

public String getStringValue()
                      throws XPathException

Description copied from interface: Sequence

Convert the sequence to a string.

Specified by:

getStringValue in interface Sequence

Throws:

XPathException

toString

public String toString()

Overrides:

toString in class Object

add

public abstract 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

itemAt

public abstract 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

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

nodeMoved

public void nodeMoved(NodeId oldNodeId,
                      StoredNode newNode)

Description copied from interface: Sequence

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

Specified by:

nodeMoved in interface Sequence

See Also:

UpdateListener

effectiveBooleanValue

public boolean effectiveBooleanValue()
                              throws XPathException

See 2.4.3 Effective Boolean Value

Specified by:

effectiveBooleanValue in interface Sequence

Throws:

XPathException

See Also:

Sequence.effectiveBooleanValue()

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 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 Sequence

Throws:

XPathException

clearContext

public void clearContext(int contextId)
                  throws XPathException

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

Throws:

XPathException

setSelfAsContext

public void setSelfAsContext(int contextId)
                      throws XPathException

Specified by:

setSelfAsContext in interface Sequence

Throws:

XPathException

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

isPersistentSet

public boolean isPersistentSet()

Specified by:

isPersistentSet in interface Sequence

isCacheable

public boolean isCacheable()

Specified by:

isCacheable in interface Sequence

getState

public int getState()

Specified by:

getState in interface Sequence

hasChanged

public boolean hasChanged(int previousState)

Specified by:

hasChanged in interface Sequence