org.apache.empire.xml.XMLUtil Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.empire.xml;
import java.util.Map;
import java.util.Map.Entry;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* This class provides a collection of static helper functions for common XML tasks.
* The class cannot be instanciated since all.
* methods provided are declared static.
*
*
*
*/
public class XMLUtil
{
protected static final Logger log = LoggerFactory.getLogger(XMLUtil.class);
/**
* DocumentBuilder that is aware of namespaces. This is necessary for parsing xsl files.
*/
private static DocumentBuilder documentBuilder = null;
/* Static initializer: */
static
{
/* Instantiate a DocumentBuilderFactory. */
DocumentBuilderFactory dFactory = DocumentBuilderFactory.newInstance();
/* And setNamespaceAware, which is required when parsing xsl files. */
dFactory.setNamespaceAware(true);
try
{
/* Use the DocumentBuilderFactory to create a DocumentBuilder. */
documentBuilder = dFactory.newDocumentBuilder();
} catch (ParserConfigurationException e)
{
log.error("XMLUtil::createDocument-->", e);
e.printStackTrace();
}
}
/**
* Class contains only static functions! Constructor not available!
*/
private XMLUtil()
{
/* No instances necessary */
}
/**
* Returns a document newly created by the class's static DocumentBuilder.
*
* @return An empty DOM document.
*/
static public synchronized Document createDocument()
{
return documentBuilder.newDocument();
}
/**
* Returns an initialzed, namespace aware DocumentBuilder.
*
* @return The DocumentBuilder.
*/
static public DocumentBuilder getDocumentBuilder()
{
return documentBuilder;
}
static public synchronized Element createDocument(String rootElemName)
{
// create document
Document doc = createDocument();
Element root = doc.createElement(rootElemName);
doc.appendChild(root);
return root;
}
static public synchronized Element createDocumentNS(String prefix, String rootElemName, Map nsMap)
{
// create document
Document doc = createDocument();
// prefix
Element root = null;
if (prefix != null && prefix.length() > 0)
{ // Find matching URI
String uri = nsMap.get(prefix);
if (uri == null)
{
log.error("Namespace URI for namespace " + prefix + " not found!");
return null;
}
// create Document
root = doc.createElementNS(uri, prefix + ":" + rootElemName);
}
else
{
root = doc.createElement(rootElemName);
}
doc.appendChild(root);
// Add Namespace attributes
addNamespaceURIs(doc, nsMap);
return root;
}
static public boolean addNamespaceURIs(Document doc, Map nsMap)
{
Element root = doc.getDocumentElement();
if (root == null)
return false;
// Add Namespace attributes
for(Entry entry:nsMap.entrySet())
{
root.setAttribute("xmlns:" + entry.getKey(), entry.getValue());
}
return true;
}
static public String getNamespaceURI(Document doc, String prefix)
{
Element e = doc.getDocumentElement();
return e.getAttributeNS("", prefix);
}
/**
* Gets the first (direct) child Element.
*
* @param parent the parent element below which to search the child
* @return the first child element, or null otherwise
*/
static public Element getFirstChild(Node parent)
{ // Child Element suchen
if (parent == null)
return null;
Node node = parent.getFirstChild();
while (node != null)
{ // Find all Element nodes
if (node.getNodeType() == Node.ELEMENT_NODE)
return (Element) node; // found
node = node.getNextSibling();
}
return null; // not found!
}
/**
* Finds the first (direct) child Element with a given tag name.
*
* @param parent the parent element below which to search the child
* @param tagName the (tag) name of the desired child element
* @return the child element if an element of that name existed, or null otherwise
*/
static public Element findFirstChild(Node parent, String tagName)
{ // Child Element suchen
if (parent == null)
return null;
Node node = parent.getFirstChild();
while (node != null)
{ // Find all Element nodes
if (node.getNodeType() == Node.ELEMENT_NODE)
{ // check name
Element elem = (Element) node;
if (tagName.equalsIgnoreCase(elem.getTagName()))
return elem; // found
}
node = node.getNextSibling();
}
return null; // not found!
}
/**
* Returns the next sibling Element for an element, optionally matching tag names.
*
* @param child the element from which to search for a next sibling
* @param sameName true to retrive the next sibling element of the same name, of false if any name is allowed
* @return the next sibling element if one exists, or null otherwise
*/
static public Element getNextSiblingElement(Element child, boolean sameName)
{ // Child Element suchen
if (child == null)
return null;
String name = child.getTagName();
Node node = child.getNextSibling();
while (node != null)
{ // Find all Element nodes
if (node.getNodeType() == Node.ELEMENT_NODE)
{ // check name
Element elem = (Element) node;
if (sameName && name.equalsIgnoreCase(elem.getTagName()))
return elem; // found
}
node = node.getNextSibling();
}
return null; // not found!
}
/**
* Finds the first (direct) child element with a given tag name and attribute.
*
* @param parent the parent element below which to search the child
* @param tagName the (tag) name of the desired child element
* @param attrName the name of the attribute which value must match the given value
* @param value the attribute value to which elements are matched.
* @return the child element if an element of that name existed, or null otherwise
*/
static public Element findFirstChildWithAttrib(Node parent, String tagName, String attrName, Object value)
{
Element elem = findFirstChild(parent, tagName);
if (attrName == null)
return null;
while (elem != null)
{ // Check Value
String attrValue = elem.getAttribute(attrName);
if (attrValue == null || attrValue.length() < 1)
{ // Attribute is null
if (value == null)
break; // gefunden!
}
else
{ // Attribute is not null
if (attrValue.equals(value.toString()))
break; // gefunden!
}
// next
elem = getNextSiblingElement(elem, true);
}
return elem;
}
/**
* Finds the first element which name matchtes a given tag name
* that is locacted anywhere below the given parent.
*
* @param parent the parent element below which to search the child
* @param tagName the (tag) name of the desired child element
* @return the child element if an element of that name existed, or null otherwise
*/
static public Element findFirstChildDeep(Element parent, String tagName)
{ // Child Element suchen
if (parent == null)
return null;
NodeList nl = parent.getElementsByTagName(tagName);
for (int i = 0; i < nl.getLength(); i++)
{
if (nl.item(i).getNodeType() == Node.ELEMENT_NODE)
return (Element) nl.item(i);
}
return null;
}
/**
* Returns the first element which name matchtes a given tag name.
*
* @param doc the xml document in which to find an element of the given name
* @param tagName the (tag) name of the desired child element
* @return the child element if an element of that name existed, or null otherwise
*/
static public Element findFirstChildDeep(Document doc, String tagName)
{ // Child Element suchen
if (doc == null)
return null;
return findFirstChildDeep(doc.getDocumentElement(), tagName);
}
/**
* Retrieves the text of a given element.
*
* @param elem the Element for which the text value is requested
* @return the text value of that element or null if the element has no text value
*/
static public String getElementText(Node elem)
{
String value = null;
Node node = (elem != null) ? elem.getFirstChild() : null;
// Find Text
while (node != null)
{ // Find all Text nodes
if (node.getNodeType() == Node.TEXT_NODE)
{ // set or append
if (value == null)
value = node.getNodeValue();
else
value += node.getNodeValue();
}
node = node.getNextSibling();
}
return value;
}
/**
* Sets the text value of an Element. if current text of the element is
* replaced with the new text if text is null any
* current text value is deleted.
*
* @param elem the Element for which the text value should be set
* @param text the new text value of the element
* @return true if the text could be set or false otherwise
*/
static public boolean setElementText(Node elem, Object text)
{
if (elem == null)
return false; // Fehler
// Find Text
Node node = elem.getFirstChild();
while (node != null)
{ // Find all Text nodes
if (node.getNodeType() == Node.TEXT_NODE)
break; // gefunden
node = node.getNextSibling();
}
if (node != null)
{ // Set or remove text
if (text != null)
node.setNodeValue(text.toString());
else
elem.removeChild(node);
}
else if (text != null)
{ // Add Text
elem.appendChild(elem.getOwnerDocument().createTextNode(text.toString()));
}
return true;
}
/**
* Adds a new child element to a parent.
*
* @param parent the Element to which to append the child
* @param name the (tag) name of the new child
* @param value the text value of the new element. (can be null!)
* @return the new child element
*/
static public Element addElement(Node parent, String name, String value)
{
if (parent == null)
return null; // Fehler
// Name must not contain spaces
if (name.indexOf(' ')>=0)
name = name.replace(' ', '_');
// Create Element
Element child = parent.getOwnerDocument().createElement(name);
if (value != null)
setElementText(child, value);
parent.appendChild(child);
return child;
}
/**
* Adds a child element to the parent.
*
* @param parent
* @param name
* @return the newly created child element
*/
static public Element addElement(Element parent, String name)
{
return addElement(parent, name, null);
}
/**
* Adds a new child element to a parent with a namespace.
*
* @param parent the Element to which to append the child
* @param prefix the name of the namespace this element belongs to
* @param name the (tag) name of the new child
* @param value the text value of the new element. (can be null!)
* @return the new child element
*/
static public Element addElementNS(Node parent, String prefix, String name, String value)
{
if (parent == null)
return null; // Fehler
// URI
if (prefix == null || prefix.length() == 0)
return addElement(parent, name, value);
// Find matching URI
Document doc = parent.getOwnerDocument();
String uri = getNamespaceURI(doc, prefix);
if (uri == null)
{
log.error("Namespace URI for namespace " + prefix + " not found!");
return null;
}
Element child = doc.createElementNS(uri, prefix + ":" + name);
if (value != null)
setElementText(child, value);
parent.appendChild(child);
return child;
}
static public Element addElementNS(Element parent, String prefix, String name)
{
return addElementNS(parent, prefix, name, null);
}
/**
* Inserts a new child element to a parent.
*
* @param parent the Element to which to append the child
* @param name the (tag) name of the new child
* @param value the text value of the new element. (can be null!)
* @param pos the inserted element will be placed before this element
*
* @return the new child element
*/
static public Element insertElement(Node parent, String name, String value, Element pos)
{
if (parent == null)
return null; // Fehler
Element child = parent.getOwnerDocument().createElement(name);
if (value != null)
setElementText(child, value);
// insert now
parent.insertBefore(child, pos);
return child;
}
static public Element insertElement(Node parent, String name, Element pos)
{
return insertElement(parent, name, null, pos);
}
/**
* Inserts a new child element to a parent.
*
* @param parent the Element to which to append the child
* @param prefix
* @param name the (tag) name of the new child
* @param value the text value of the new element. (can be null!)
* @param pos pos the inserted element will be placed before this element
*
* @return the new child element
*/
static public Element insertElementNS(Node parent, String prefix, String name, String value, Element pos)
{
if (parent == null)
return null; // Fehler
// Has prefix?
if (prefix == null || prefix.length() == 0)
return insertElement(parent, name, value, pos);
// Find matching URI
Document doc = parent.getOwnerDocument();
String uri = getNamespaceURI(doc, prefix);
if (uri == null)
{
log.error("Namespace URI for namespace " + prefix + " not found!");
return null;
}
Element child = doc.createElementNS(uri, prefix + ":" + name);
if (value != null)
setElementText(child, value);
// insert now
parent.insertBefore(child, pos);
return child;
}
static public Element insertElementNS(Node parent, String prefix, String name, Element pos)
{
return insertElementNS(parent, prefix, name, null, pos);
}
/**
* Returns the text value of a given child element.
*
* @param parent the Element which contains the child
* @param childName the (tag) name of the child
* @return the text value of the child or null if no child exists or the child does not have a text value
*/
static public String getChildText(Node parent, String childName)
{
Element elem = findFirstChild(parent, childName);
if (elem == null)
return null; // not Found!
return getElementText(elem);
}
/**
* Changes the tag name of an element.
*
* @param elem Element which name should be changed
* @param newName new tag name of the element
* @return true if the name was changed successfully or false otherwise
*/
static public boolean changeTagName(Element elem, String newName)
{
if (elem == null)
return false; // not Found!
Document doc = elem.getOwnerDocument();
Element newElem = doc.createElement(newName);
// Copy the attributes to the new element
NamedNodeMap attrs = elem.getAttributes();
for (int i = 0; i < attrs.getLength(); i++)
{
Attr attr2 = (Attr) doc.importNode(attrs.item(i), true);
newElem.getAttributes().setNamedItem(attr2);
}
// Copy all Child Elements
for (Node node = elem.getFirstChild(); node != null; node = node.getNextSibling())
newElem.appendChild(node.cloneNode(true));
// insert
Node parent = elem.getParentNode();
parent.replaceChild(newElem, elem);
return true;
}
}