org.apache.xpath.domapi
Class XPathResultImpl

java.lang.Object
  org.apache.xpath.domapi.XPathResultImpl

All Implemented Interfaces:

org.w3c.dom.events.EventListener

 class XPathResultImpl
extends java.lang.Object
implements org.w3c.dom.events.EventListener

The class provides an implementation XPathResult according to the DOM L3 XPath Specification, Working Group Note 26 February 2004.

See also the Document Object Model (DOM) Level 3 XPath Specification.

The XPathResult interface represents the result of the evaluation of an XPath expression within the context of a particular node. Since evaluation of an XPath expression can result in various result types, this object makes it possible to discover and manipulate the type and value of the result.

This implementation wraps an XObject.

See Also:

XObject, org.w3c.dom.xpath.XPathResult

Field Summary

private org.w3c.dom.Node	m_contextNode Only used to attach a mutation event handler when specified type is an iterator type.
private boolean	m_isInvalidIteratorState
private org.w3c.dom.traversal.NodeIterator	m_iterator The iterator, if this is an iterator type.
private org.w3c.dom.NodeList	m_list The list, if this is a snapshot type.
private XObject	m_resultObj The wrapped XObject
private short	m_resultType This the type specified by the user during construction.
private XPath	m_xpath The xpath object that wraps the expression used for this result.

Constructor Summary

XPathResultImpl(short type, XObject result, org.w3c.dom.Node contextNode, XPath xpath)
Constructor for XPathResultImpl.

Method Summary

private void	addEventListener() Add m_contextNode to Event Listner to listen for Mutations Events
boolean	getBooleanValue()
boolean	getInvalidIteratorState()
double	getNumberValue() The value of this number result.
short	getResultType()
org.w3c.dom.Node	getSingleNodeValue() The value of this single node result, which may be null.
int	getSnapshotLength() The number of nodes in the result snapshot.
java.lang.String	getStringValue() The value of this string result.
private short	getTypeFromXObject(XObject object) Given an XObject, determine the corresponding DOM XPath type
private java.lang.String	getTypeString(int type) Given a request type, return the equivalent string.
void	handleEvent(org.w3c.dom.events.Event event)
private boolean	isNamespaceNode(org.w3c.dom.Node node) Given a node, determine if it is a namespace node.
(package private) static boolean	isValidType(short type) Check if the specified type is one of the supported types.
org.w3c.dom.Node	iterateNext() Iterates and returns the next node from the node set or nullif there are no more nodes.
private void	removeEventListener() Remove m_contextNode to Event Listner to listen for Mutations Events
org.w3c.dom.Node	snapshotItem(int index) Returns the indexth item in the snapshot collection.

Methods inherited from class java.lang.Object

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

Field Detail

m_resultObj

private final XObject m_resultObj

The wrapped XObject

m_xpath

private final XPath m_xpath

The xpath object that wraps the expression used for this result.

m_resultType

private final short m_resultType

This the type specified by the user during construction. Typically the constructor will be called by org.apache.xpath.XPath.evaluate().

m_isInvalidIteratorState

private boolean m_isInvalidIteratorState

m_contextNode

private final org.w3c.dom.Node m_contextNode

Only used to attach a mutation event handler when specified type is an iterator type.

m_iterator

private org.w3c.dom.traversal.NodeIterator m_iterator

The iterator, if this is an iterator type.

m_list

private org.w3c.dom.NodeList m_list

The list, if this is a snapshot type.

Constructor Detail

XPathResultImpl

XPathResultImpl(short type,
                XObject result,
                org.w3c.dom.Node contextNode,
                XPath xpath)

Constructor for XPathResultImpl. For internal use only.

Method Detail

getResultType

public short getResultType()

See Also:

org.w3c.dom.xpath.XPathResult#getResultType()

getNumberValue

public double getNumberValue()
                      throws XPathException

The value of this number result.

Throws:

XPathException - TYPE_ERR: raised if resultType is not NUMBER_TYPE.

See Also:

org.w3c.dom.xpath.XPathResult#getNumberValue()

getStringValue

public java.lang.String getStringValue()
                                throws XPathException

The value of this string result.

Throws:

XPathException - TYPE_ERR: raised if resultType is not STRING_TYPE.

See Also:

org.w3c.dom.xpath.XPathResult#getStringValue()

getBooleanValue

public boolean getBooleanValue()
                        throws XPathException

Throws:

XPathException

See Also:

org.w3c.dom.xpath.XPathResult#getBooleanValue()

getSingleNodeValue

public org.w3c.dom.Node getSingleNodeValue()
                                    throws XPathException

The value of this single node result, which may be null.

Throws:

XPathException - TYPE_ERR: raised if resultType is not ANY_UNORDERED_NODE_TYPE or FIRST_ORDERED_NODE_TYPE.

See Also:

org.w3c.dom.xpath.XPathResult#getSingleNodeValue()

getInvalidIteratorState

public boolean getInvalidIteratorState()

See Also:

org.w3c.dom.xpath.XPathResult#getInvalidIteratorState()

getSnapshotLength

public int getSnapshotLength()
                      throws XPathException

The number of nodes in the result snapshot. Valid values for snapshotItem indices are 0 to snapshotLength-1 inclusive.

Throws:

XPathException - TYPE_ERR: raised if resultType is not UNORDERED_NODE_SNAPSHOT_TYPE or ORDERED_NODE_SNAPSHOT_TYPE.

See Also:

org.w3c.dom.xpath.XPathResult#getSnapshotLength()

iterateNext

public org.w3c.dom.Node iterateNext()
                             throws XPathException,
                                    org.w3c.dom.DOMException

Iterates and returns the next node from the node set or nullif there are no more nodes.

Returns:

Returns the next node.

Throws:

XPathException - TYPE_ERR: raised if resultType is not UNORDERED_NODE_ITERATOR_TYPE or ORDERED_NODE_ITERATOR_TYPE.

org.w3c.dom.DOMException - INVALID_STATE_ERR: The document has been mutated since the result was returned.

See Also:

org.w3c.dom.xpath.XPathResult#iterateNext()

snapshotItem

public org.w3c.dom.Node snapshotItem(int index)
                              throws XPathException

Returns the indexth item in the snapshot collection. If index is greater than or equal to the number of nodes in the list, this method returns null. Unlike the iterator result, the snapshot does not become invalid, but may not correspond to the current document if it is mutated.

Parameters:

index - Index into the snapshot collection.

Returns:

The node at the indexth position in the NodeList, or null if that is not a valid index.

Throws:

XPathException - TYPE_ERR: raised if resultType is not UNORDERED_NODE_SNAPSHOT_TYPE or ORDERED_NODE_SNAPSHOT_TYPE.

See Also:

org.w3c.dom.xpath.XPathResult#snapshotItem(int)

isValidType

static boolean isValidType(short type)

Check if the specified type is one of the supported types.

Parameters:

type - The specified type

Returns:

true If the specified type is supported; otherwise, returns false.

handleEvent

public void handleEvent(org.w3c.dom.events.Event event)

Specified by:

handleEvent in interface org.w3c.dom.events.EventListener

See Also:

EventListener.handleEvent(Event)

getTypeString

private java.lang.String getTypeString(int type)

Given a request type, return the equivalent string. For diagnostic purposes.

Returns:

type string

getTypeFromXObject

private short getTypeFromXObject(XObject object)

Given an XObject, determine the corresponding DOM XPath type

Returns:

type string

isNamespaceNode

private boolean isNamespaceNode(org.w3c.dom.Node node)

Given a node, determine if it is a namespace node.

Parameters:

node -

Returns:

boolean Returns true if this is a namespace node; otherwise, returns false.

addEventListener

private void addEventListener()

Add m_contextNode to Event Listner to listen for Mutations Events

removeEventListener

private void removeEventListener()

Remove m_contextNode to Event Listner to listen for Mutations Events