chaschev.util.DomUtils Maven / Gradle / Ivy
package chaschev.util;
import org.w3c.dom.*;
import org.xml.sax.SAXException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.*;
import static org.w3c.dom.Node.ELEMENT_NODE;
/**
* User: achaschev
* Date: 4/5/13
* Time: 3:46 PM
*/
public class DomUtils {
public static final Predicate TRUE = new Predicate() {
public boolean apply(Node node) {
return true;
}
};
public interface Predicate {
/**
* Applies this Predicate to the given object.
*
* @return the value of this Predicate when applied to input {@code t}
*/
boolean apply(T t);
}
public static Element child(Element element, String tag) {
final NodeList list = element.getChildNodes();
for (int i = 0; i < list.getLength(); i++) {
final Node item = list.item(i);
if (item.getNodeType() == ELEMENT_NODE && hasLocalName(item, tag)) {
return (Element) item;
}
}
return null;
}
public static boolean hasLocalName(Node item, String tag) {
final String nodeName = item.getNodeName();
if (nodeName.endsWith(tag)) {
int i = nodeName.length() - tag.length();
return i == 0 || nodeName.charAt(i - 1) == ':';
}
return false;
}
public static Element childPath(Element element, String path) {
final String[] elements = path.split("/");
for (String s : elements) {
element = child(element, s);
if (element == null) return null;
}
return element;
}
public static Iterable children(final Element element, final String tag) {
return children(element, new Predicate() {
@Override
public boolean apply(Node node) {
return hasLocalName(node, tag);
}
});
}
public static Iterable children(final Element element) {
return children(element, TRUE);
}
public static Iterable children(final Element element, final Predicate predicate) {
return new Iterable() {
@Override
public Iterator iterator() {
return new Iterator() {
final NodeList list = element.getChildNodes();
int i = 0;
@Override
public boolean hasNext() {
for (; i < list.getLength(); i++) {
final Node node = list.item(i);
if (node.getNodeType() == ELEMENT_NODE && predicate.apply(node)) {
break;
}
}
return i < list.getLength();
}
@Override
public Element next() {
return (Element) list.item(i++);
}
@Override
public void remove() {
throw new UnsupportedOperationException("todo .remove");
}
};
}
};
}
/**
* First tries to get the attribute value by doing an getAttributeNS on the element, if that gets an empty element it does a getAttribute without namespace.
*/
public static String getAttribute(Element element, String attribute) {
return element.getAttribute(attribute);
}
/**
* Gets all descendant elements of the given parentElement with the given namespace and tagname and returns their text child as a list of String.
*/
public static List childrenText(Element parentElement, String tagname) {
final Iterable children = children(parentElement, tagname);
List result = new ArrayList();
for (Element element : children) {
result.add(elementText(element));
}
return result;
}
/**
* The contents of all Text nodes that are children of the given parentElement.
* The result is trim()-ed.
*
* The reason for this more complicated procedure instead of just returning the data of the firstChild is that
* when the text is Chinese characters then on Android each Characater is represented in the DOM as
* an individual Text node.
*
* @param parentElement
* @return
*/
public static String elementText(Element parentElement) {
if (parentElement == null) {
return null;
}
StringBuilder result = new StringBuilder();
NodeList childNodes = parentElement.getChildNodes();
for (int i = 0; i < childNodes.getLength(); i++) {
Node node = childNodes.item(i);
if ((node == null) ||
(node.getNodeType() != Node.TEXT_NODE)) {
continue;
}
result.append(((Text) node).getData());
}
return result.toString().trim();
}
public static String elementToString(Node n) {
return elementToString(n, 0, 4);
}
public static String elementToString(Node node, int depth, int maxDepth) {
return elementToString(node, new HashSet(), depth, maxDepth);
}
private static String elementToString(Node n, Set visitedSet, int depth, int maxDepth) {
if (depth >= maxDepth) {
return "depth limit\n";
}
if (visitedSet.contains(n)) {
return "cycle to " + n.getLocalName() + "\n";
} else {
visitedSet.add(n);
}
String name = n.getNodeName();
short type = n.getNodeType();
if (Node.CDATA_SECTION_NODE == type) {
return "');
} else {
sb.append("/>").append('\n');
}
} else {
sb.append('>').append('\n');
boolean hasValidChildren = false;
for (int i = 0; i < children.getLength(); i++) {
String childToString = elementToString(children.item(i), visitedSet, depth + 1, maxDepth);
if (!"".equals(childToString)) {
sb.append(childToString);
hasValidChildren = true;
}
}
if (!hasValidChildren && ((textContent = getTextContent(n)) != null)) {
sb.append(textContent);
}
sb.append("');
}
return sb.toString();
}
public static String getTextContent(Node n) {
if (n == null) return null;
Node n1 = getChild(n, Node.TEXT_NODE);
if (n1 == null) return null;
String s1 = n1.getNodeValue();
return s1.trim();
}
/**
* Get the first direct child with a given type
*/
public static Node getChild(Node parent, int type) {
Node n = parent.getFirstChild();
while (n != null && type != n.getNodeType()) {
n = n.getNextSibling();
}
if (n == null) return null;
return n;
}
public static Document parseXml(String s){
try {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
dbFactory.setIgnoringElementContentWhitespace(true);
dbFactory.setNamespaceAware(false);
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(new ByteArrayInputStream(s.getBytes()));
return doc;
} catch (Exception e) {
throw Exceptions.runtime(e);
}
}
}
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