org.w3c.dom.xpath
Interface XPathResult

public interface XPathResult

The XPathResult interface represents the result of the evaluation of an XPath 1.0 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.

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

Field Summary

static short	ANY_TYPE This code does not represent a specific type.
static short	ANY_UNORDERED_NODE_TYPE The result is a node set as defined by [XPath 1.0] and will be accessed as a single node, which may be nullif the node set is empty.
static short	BOOLEAN_TYPE The result is a boolean as defined by [XPath 1.0].
static short	FIRST_ORDERED_NODE_TYPE The result is a node set as defined by [XPath 1.0] and will be accessed as a single node, which may be null if the node set is empty.
static short	NUMBER_TYPE The result is a number as defined by [XPath 1.0].
static short	ORDERED_NODE_ITERATOR_TYPE The result is a node set as defined by [XPath 1.0] that will be accessed iteratively, which will produce document-ordered nodes.
static short	ORDERED_NODE_SNAPSHOT_TYPE The result is a node set as defined by [XPath 1.0] that will be accessed as a snapshot list of nodes that will be in original document order.
static short	STRING_TYPE The result is a string as defined by [XPath 1.0].
static short	UNORDERED_NODE_ITERATOR_TYPE The result is a node set as defined by [XPath 1.0] that will be accessed iteratively, which may not produce nodes in a particular order.
static short	UNORDERED_NODE_SNAPSHOT_TYPE The result is a node set as defined by [XPath 1.0] that will be accessed as a snapshot list of nodes that may not be in a particular order.

Method Summary

boolean	getBooleanValue() The value of this boolean result.
boolean	getInvalidIteratorState() Signifies that the iterator has become invalid.
double	getNumberValue() The value of this number result.
short	getResultType() A code representing the type of this result, as defined by the type constants.
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.
Node	iterateNext() Iterates and returns the next node from the node set or nullif there are no more nodes.
Node	snapshotItem(int index) Returns the indexth item in the snapshot collection.

Field Detail

ANY_TYPE

public static final short ANY_TYPE

This code does not represent a specific type. An evaluation of an XPath expression will never produce this type. If this type is requested, then the evaluation returns whatever type naturally results from evaluation of the expression.
If the natural result is a node set when ANY_TYPE was requested, then UNORDERED_NODE_ITERATOR_TYPE is always the resulting type. Any other representation of a node set must be explicitly requested.

NUMBER_TYPE

public static final short NUMBER_TYPE

The result is a number as defined by [XPath 1.0]. Document modification does not invalidate the number, but may mean that reevaluation would not yield the same number.

STRING_TYPE

public static final short STRING_TYPE

The result is a string as defined by [XPath 1.0]. Document modification does not invalidate the string, but may mean that the string no longer corresponds to the current document.

BOOLEAN_TYPE

public static final short BOOLEAN_TYPE

The result is a boolean as defined by [XPath 1.0]. Document modification does not invalidate the boolean, but may mean that reevaluation would not yield the same boolean.

UNORDERED_NODE_ITERATOR_TYPE

public static final short UNORDERED_NODE_ITERATOR_TYPE

The result is a node set as defined by [XPath 1.0] that will be accessed iteratively, which may not produce nodes in a particular order. Document modification invalidates the iteration.
This is the default type returned if the result is a node set and ANY_TYPE is requested.

ORDERED_NODE_ITERATOR_TYPE

public static final short ORDERED_NODE_ITERATOR_TYPE

The result is a node set as defined by [XPath 1.0] that will be accessed iteratively, which will produce document-ordered nodes. Document modification invalidates the iteration.

UNORDERED_NODE_SNAPSHOT_TYPE

public static final short UNORDERED_NODE_SNAPSHOT_TYPE

The result is a node set as defined by [XPath 1.0] that will be accessed as a snapshot list of nodes that may not be in a particular order. Document modification does not invalidate the snapshot but may mean that reevaluation would not yield the same snapshot and nodes in the snapshot may have been altered, moved, or removed from the document.

ORDERED_NODE_SNAPSHOT_TYPE

public static final short ORDERED_NODE_SNAPSHOT_TYPE

The result is a node set as defined by [XPath 1.0] that will be accessed as a snapshot list of nodes that will be in original document order. Document modification does not invalidate the snapshot but may mean that reevaluation would not yield the same snapshot and nodes in the snapshot may have been altered, moved, or removed from the document.

ANY_UNORDERED_NODE_TYPE

public static final short ANY_UNORDERED_NODE_TYPE

The result is a node set as defined by [XPath 1.0] and will be accessed as a single node, which may be nullif the node set is empty. Document modification does not invalidate the node, but may mean that the result node no longer corresponds to the current document. This is a convenience that permits optimization since the implementation can stop once any node in the resulting set has been found.
If there is more than one node in the actual result, the single node returned might not be the first in document order.

FIRST_ORDERED_NODE_TYPE

public static final short FIRST_ORDERED_NODE_TYPE

The result is a node set as defined by [XPath 1.0] and will be accessed as a single node, which may be null if the node set is empty. Document modification does not invalidate the node, but may mean that the result node no longer corresponds to the current document. This is a convenience that permits optimization since the implementation can stop once the first node in document order of the resulting set has been found.
If there are more than one node in the actual result, the single node returned will be the first in document order.

Method Detail

getResultType

public short getResultType()

A code representing the type of this result, as defined by the type constants.

getNumberValue

public double getNumberValue()
                      throws XPathException

The value of this number result. If the native double type of the DOM binding does not directly support the exact IEEE 754 result of the XPath expression, then it is up to the definition of the binding to specify how the XPath number is converted to the native binding number.

Throws:

XPathException - TYPE_ERR: raised if resultType is not NUMBER_TYPE.

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.

getBooleanValue

public boolean getBooleanValue()
                        throws XPathException

The value of this boolean result.

Throws:

XPathException - TYPE_ERR: raised if resultType is not BOOLEAN_TYPE.

getSingleNodeValue

public 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.

getInvalidIteratorState

public boolean getInvalidIteratorState()

Signifies that the iterator has become invalid. True if resultType is UNORDERED_NODE_ITERATOR_TYPE or ORDERED_NODE_ITERATOR_TYPE and the document has been modified since this result was returned.

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.

iterateNext

public Node iterateNext()
                 throws XPathException,
                        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.

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

snapshotItem

public 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.