at.gv.egovernment.moa.util
Class XPathUtils

java.lang.Object
  |
  +--at.gv.egovernment.moa.util.XPathUtils

public class XPathUtils

extends Object

Utility methods to evaluate XPath expressions on DOM nodes.

Version:

$Id$

Author:

Patrick Peck

Field Summary

static String

ALL_NODES_XPATH The XPath expression selecting all nodes under a given root (including the root node itself).

Constructor Summary

XPathUtils()

Method Summary

static String	getAttributeValue(org.w3c.dom.Element root, String xpath, String def) Return the value of a DOM attribute whose location is given by an XPath expression.
static String	getElementValue(org.w3c.dom.Element root, String xpath, String def) Return the value of a DOM element whose location is given by an XPath expression.
static org.w3c.dom.traversal.NodeIterator	selectNodeIterator(org.w3c.dom.Node contextNode, org.w3c.dom.Element namespaceElement, String exp) Return a NodeIterator over the nodes matching the XPath expression.
static org.w3c.dom.traversal.NodeIterator	selectNodeIterator(org.w3c.dom.Node contextNode, Map namespaceMapping, String exp) Return a NodeIterator over the nodes matching the XPath expression.
static org.w3c.dom.traversal.NodeIterator	selectNodeIterator(org.w3c.dom.Node contextNode, String exp) Return a NodeIterator over the nodes matching the XPath expression.
static org.w3c.dom.NodeList	selectNodeList(org.w3c.dom.Node contextNode, org.w3c.dom.Element namespaceElement, String exp) Return a NodeList of all the nodes matching the XPath expression.
static org.w3c.dom.NodeList	selectNodeList(org.w3c.dom.Node contextNode, Map namespaceMapping, String exp) Return a NodeList of all the nodes matching the XPath expression.
static org.w3c.dom.NodeList	selectNodeList(org.w3c.dom.Node contextNode, String exp) Return a NodeList of all the nodes matching the XPath expression.
static org.w3c.dom.Node	selectSingleNode(org.w3c.dom.Node contextNode, org.w3c.dom.Element namespaceElement, String exp) Select the first node matching an XPath expression.
static org.w3c.dom.Node	selectSingleNode(org.w3c.dom.Node contextNode, Map namespaceMapping, String exp) Select the first node matching an XPath expression.
static org.w3c.dom.Node	selectSingleNode(org.w3c.dom.Node contextNode, String exp) Select the first node matching an XPath expression.

Methods inherited from class java.lang.Object

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

Field Detail

ALL_NODES_XPATH

public static final String ALL_NODES_XPATH

The XPath expression selecting all nodes under a given root (including the root node itself).

Constructor Detail

XPathUtils

public XPathUtils()

Method Detail

selectNodeIterator

public static org.w3c.dom.traversal.NodeIterator selectNodeIterator(org.w3c.dom.Node contextNode,
                                                                    String exp)
                                                             throws XPathException

Return a NodeIterator over the nodes matching the XPath expression. All namespace URIs and prefixes declared in the Constants interface are used for resolving namespaces.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

exp - The XPath expression to evaluate.

Returns:

An iterator over the resulting nodes.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectNodeIterator

public static org.w3c.dom.traversal.NodeIterator selectNodeIterator(org.w3c.dom.Node contextNode,
                                                                    org.w3c.dom.Element namespaceElement,
                                                                    String exp)
                                                             throws XPathException

Return a NodeIterator over the nodes matching the XPath expression.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

namespaceElement - An element from which to build the namespace mapping for evaluating the XPath expression

exp - The XPath expression to evaluate.

Returns:

An iterator over the resulting nodes.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectNodeIterator

public static org.w3c.dom.traversal.NodeIterator selectNodeIterator(org.w3c.dom.Node contextNode,
                                                                    Map namespaceMapping,
                                                                    String exp)
                                                             throws XPathException

Return a NodeIterator over the nodes matching the XPath expression.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

namespaceMapping - A namespace prefix to namespace URI mapping (String to String) for evaluating the XPath expression.

exp - The XPath expression to evaluate.

Returns:

An iterator over the resulting nodes.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectNodeList

public static org.w3c.dom.NodeList selectNodeList(org.w3c.dom.Node contextNode,
                                                  String exp)
                                           throws XPathException

Return a NodeList of all the nodes matching the XPath expression. All namespace URIs and prefixes declared in the Constants interface are used for resolving namespaces.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

exp - The XPath expression to evaluate.

Returns:

A NodeList containing the matching nodes.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectNodeList

public static org.w3c.dom.NodeList selectNodeList(org.w3c.dom.Node contextNode,
                                                  org.w3c.dom.Element namespaceElement,
                                                  String exp)
                                           throws XPathException

Return a NodeList of all the nodes matching the XPath expression.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

namespaceElement - An element from which to build the namespace mapping for evaluating the XPath expression

exp - The XPath expression to evaluate.

Returns:

A NodeList containing the matching nodes.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectNodeList

public static org.w3c.dom.NodeList selectNodeList(org.w3c.dom.Node contextNode,
                                                  Map namespaceMapping,
                                                  String exp)
                                           throws XPathException

Return a NodeList of all the nodes matching the XPath expression.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

namespaceMapping - A namespace prefix to namespace URI mapping (String to String) for evaluating the XPath expression.

exp - The XPath expression to evaluate.

Returns:

A NodeList containing the matching nodes.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectSingleNode

public static org.w3c.dom.Node selectSingleNode(org.w3c.dom.Node contextNode,
                                                String exp)
                                         throws XPathException

Select the first node matching an XPath expression. All namespace URIs and prefixes declared in the Constants interface are used for resolving namespaces.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

exp - The XPath expression to evaluate.

Returns:

Node The first node matching the XPath expression, or null, if no node matched.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectSingleNode

public static org.w3c.dom.Node selectSingleNode(org.w3c.dom.Node contextNode,
                                                org.w3c.dom.Element namespaceElement,
                                                String exp)
                                         throws XPathException

Select the first node matching an XPath expression.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

namespaceElement - An element from which to build the namespace mapping for evaluating the XPath expression

exp - The XPath expression to evaluate.

Returns:

Node The first node matching the XPath expression, or null, if no node matched.

Throws:

XPathException - An error occurred evaluating the XPath expression.

selectSingleNode

public static org.w3c.dom.Node selectSingleNode(org.w3c.dom.Node contextNode,
                                                Map namespaceMapping,
                                                String exp)
                                         throws XPathException

Select the first node matching an XPath expression.

Parameters:

contextNode - The root node from which to evaluate the XPath expression.

namespaceMapping - A namespace prefix to namespace URI mapping (String to String) for evaluating the XPath expression.

exp - The XPath expression to evaluate.

Returns:

Node The first node matching the XPath expression, or null, if no node matched.

Throws:

XPathException - An error occurred evaluating the XPath expression.

getElementValue

public static String getElementValue(org.w3c.dom.Element root,
                                     String xpath,
                                     String def)

Return the value of a DOM element whose location is given by an XPath expression.

Parameters:

root - The root element from which to evaluate the XPath.

xpath - The XPath expression pointing to the element whose value to return.

def - The default value to return, if no element can be found using the given xpath.

Returns:

The element value, if it can be located using the xpath. Otherwise, def is returned.

getAttributeValue

public static String getAttributeValue(org.w3c.dom.Element root,
                                       String xpath,
                                       String def)

Return the value of a DOM attribute whose location is given by an XPath expression.

Parameters:

root - The root element from which to evaluate the XPath.

xpath - The XPath expression pointing to the attribute whose value to return.

def - The default value to return, if no attribute can be found using the given xpath.

Returns:

The element value, if it can be located using the xpath. Otherwise, def is returned.