org.apache.cocoon.xml.dom
Class DomHelper

java.lang.Object
  org.apache.cocoon.xml.dom.DomHelper

public class DomHelper

extends Object

Helper class to create and retrieve information from DOM-trees. It provides some functionality comparable to what's found in Avalon's Configuration objects. These lasts one could however not be used by Cocoon Forms because they don't provide an accurate model of an XML file (no mixed content, no namespaced attributes, no namespace declarations, ...).

This class depends specifically on the Xerces DOM implementation to be able to provide information about the location of elements in their source XML file. See the getLocation(Element) method.

Version:

$Id: DomHelper.html 1304280 2012-03-23 11:18:01Z ilgrosso $

Field Summary

protected static SAXParserFactory	saxFactory
static String	XMLNS_URI

Constructor Summary

DomHelper()

Method Summary

static XMLizable	compileElementContent(Element element) Returns the content of the given Element as an object implementing the XMLizable interface.
static String	getAttribute(Element element, String attributeName) Returns the value of an element's attribute, but throws an exception if the element has no such attribute.
static String	getAttribute(Element element, String attributeName, String defaultValue) Returns the value of an element's attribute, or a default value if the element has no such attribute.
static boolean	getAttributeAsBoolean(Element element, String attributeName, boolean defaultValue)
static int	getAttributeAsInteger(Element element, String attributeName)
static int	getAttributeAsInteger(Element element, String attributeName, int defaultValue)
static Element	getChildElement(Element element, String namespace, String localName) Returns the first child element with the given namespace and localName, or null if there is no such element.
static Element	getChildElement(Element element, String namespace, String localName, boolean required) Returns the first child element with the given namespace and localName, or null if there is no such element and required flag is unset or throws an Exception if the "required" flag is set.
static Element[]	getChildElements(Element element, String namespace) Returns all Element children of an Element that belong to the given namespace.
static Element[]	getChildElements(Element element, String namespace, String localName) Returns all Element children of an Element that belong to the given namespace and have the given local name.
static int	getColumnLocation(Element element)
static String	getElementText(Element element)
static Map	getInheritedNSDeclarations(Element elm)
static int	getLineLocation(Element element)
static Map	getLocalNSDeclarations(Element elm)
static String	getLocation(Element element) Retrieves the location of an element node in the source file from which the Document was created.
static org.apache.cocoon.util.location.Location	getLocationObject(Element element)
static String	getSystemIdLocation(Element element)
static Document	parse(InputSource inputSource) Creates a W3C Document that remembers the location of each element in the source file.

Methods inherited from class java.lang.Object

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

Field Detail

saxFactory

protected static final SAXParserFactory saxFactory

XMLNS_URI

public static final String XMLNS_URI

See Also:

Constant Field Values

Constructor Detail

DomHelper

public DomHelper()

Method Detail

parse

public static Document parse(InputSource inputSource)
                      throws SAXException,
                             SAXNotSupportedException,
                             IOException

Creates a W3C Document that remembers the location of each element in the source file. The location of element nodes can then be retrieved using the getLocation(Element) method.

Parameters:

inputSource - the inputSource to read the document from

Throws:

SAXException

SAXNotSupportedException

IOException

getLocationObject

public static org.apache.cocoon.util.location.Location getLocationObject(Element element)

getLocation

public static String getLocation(Element element)

Retrieves the location of an element node in the source file from which the Document was created. This will only work for Document's created with the method #parse(InputSource, ServiceManager) of this class.

getSystemIdLocation

public static String getSystemIdLocation(Element element)

getLineLocation

public static int getLineLocation(Element element)

getColumnLocation

public static int getColumnLocation(Element element)

getChildElements

public static Element[] getChildElements(Element element,
                                         String namespace)

Returns all Element children of an Element that belong to the given namespace.

getChildElements

public static Element[] getChildElements(Element element,
                                         String namespace,
                                         String localName)

Returns all Element children of an Element that belong to the given namespace and have the given local name.

getChildElement

public static Element getChildElement(Element element,
                                      String namespace,
                                      String localName)

Returns the first child element with the given namespace and localName, or null if there is no such element.

getChildElement

public static Element getChildElement(Element element,
                                      String namespace,
                                      String localName,
                                      boolean required)
                               throws Exception

Returns the first child element with the given namespace and localName, or null if there is no such element and required flag is unset or throws an Exception if the "required" flag is set.

Throws:

Exception

getAttribute

public static String getAttribute(Element element,
                                  String attributeName)
                           throws Exception

Returns the value of an element's attribute, but throws an exception if the element has no such attribute.

Throws:

Exception

getAttribute

public static String getAttribute(Element element,
                                  String attributeName,
                                  String defaultValue)

Returns the value of an element's attribute, or a default value if the element has no such attribute.

getAttributeAsInteger

public static int getAttributeAsInteger(Element element,
                                        String attributeName)
                                 throws Exception

Throws:

Exception

getAttributeAsInteger

public static int getAttributeAsInteger(Element element,
                                        String attributeName,
                                        int defaultValue)
                                 throws Exception

Throws:

Exception

getAttributeAsBoolean

public static boolean getAttributeAsBoolean(Element element,
                                            String attributeName,
                                            boolean defaultValue)

getElementText

public static String getElementText(Element element)

compileElementContent

public static XMLizable compileElementContent(Element element)

Returns the content of the given Element as an object implementing the XMLizable interface. Practically speaking, the implementation uses the SaxBuffer class. The XMLizable object will be a standalone blurb of SAX events, not producing start/endDocument calls and containing all necessary namespace declarations.

getLocalNSDeclarations

public static Map getLocalNSDeclarations(Element elm)

getInheritedNSDeclarations

public static Map getInheritedNSDeclarations(Element elm)