# 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.

Since:
  1.4, DOM Level 3

- ## Field Summary

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

- ## Method Summary

  Modifier and Type
  Method
  Description
  `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.
  `String`
  `getStringValue()`
  The value of this string result.
  `Node`
  `iterateNext()`
  Iterates and returns the next node from the node set or `null`if there are no more nodes.
  `Node`
  `snapshotItem(int index)`
  Returns the `index`th item in the snapshot collection.

- ## Field Details

  - ### ANY_TYPE

    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.
    See Also:
      - Constant Field Values

  - ### NUMBER_TYPE

    static final short NUMBER_TYPE
    The result is a number as defined by . Document modification does not invalidate the number, but may mean that reevaluation would not yield the same number.
    See Also:
      - Constant Field Values

  - ### STRING_TYPE

    static final short STRING_TYPE
    The result is a string as defined by . Document modification does not invalidate the string, but may mean that the string no longer corresponds to the current document.
    See Also:
      - Constant Field Values

  - ### BOOLEAN_TYPE

    static final short BOOLEAN_TYPE
    The result is a boolean as defined by . Document modification does not invalidate the boolean, but may mean that reevaluation would not yield the same boolean.
    See Also:
      - Constant Field Values

  - ### UNORDERED_NODE_ITERATOR_TYPE

    static final short UNORDERED_NODE_ITERATOR_TYPE
    The result is a node set as defined by 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.
    See Also:
      - Constant Field Values

  - ### ORDERED_NODE_ITERATOR_TYPE

    static final short ORDERED_NODE_ITERATOR_TYPE
    The result is a node set as defined by that will be accessed iteratively, which will produce document-ordered nodes. Document modification invalidates the iteration.
    See Also:
      - Constant Field Values

  - ### UNORDERED_NODE_SNAPSHOT_TYPE

    static final short UNORDERED_NODE_SNAPSHOT_TYPE
    The result is a node set as defined by 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.
    See Also:
      - Constant Field Values

  - ### ORDERED_NODE_SNAPSHOT_TYPE

    static final short ORDERED_NODE_SNAPSHOT_TYPE
    The result is a node set as defined by 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.
    See Also:
      - Constant Field Values

  - ### ANY_UNORDERED_NODE_TYPE

    static final short ANY_UNORDERED_NODE_TYPE
    The result is a node set as defined by 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 any node in the in the resulting set has been found.
    If there are more than one node in the actual result, the single node returned might not be the first in document order.
    See Also:
      - Constant Field Values

  - ### FIRST_ORDERED_NODE_TYPE

    static final short FIRST_ORDERED_NODE_TYPE
    The result is a node set as defined by 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.
    See Also:
      - Constant Field Values

- ## Method Details

  - ### getResultType

    short getResultType()
    A code representing the type of this result, as defined by the type constants.

  - ### getNumberValue

    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 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

    String getStringValue() throws XPathException
    The value of this string result.
    Throws:
      `XPathException` - TYPE_ERR: raised if `resultType` is not `STRING_TYPE`.

  - ### getBooleanValue

    boolean getBooleanValue() throws XPathException
    The value of this boolean result.
    Throws:
      `XPathException` - TYPE_ERR: raised if `resultType` is not `BOOLEAN_TYPE`.

  - ### getSingleNodeValue

    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

    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

    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

    Node iterateNext() throws XPathException, DOMException
    Iterates and returns the next node from the node set or `null`if 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

    Node snapshotItem(int index) throws XPathException
    Returns the `index`th 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 `index`th 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`.