filebot/source/net/sourceforge/tuned/XPathUtilities.java

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package net.sourceforge.tuned;
import java.util.AbstractList;
import java.util.List;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public final class XPathUtilities {
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public static Node selectNode(String xpath, Object node) {
try {
return (Node) getXPath(xpath).evaluate(node, XPathConstants.NODE);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public static List<Node> selectNodes(String xpath, Object node) {
try {
return new NodeListDecorator((NodeList) getXPath(xpath).evaluate(node, XPathConstants.NODESET));
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public static String selectString(String xpath, Object node) {
try {
return ((String) getXPath(xpath).evaluate(node, XPathConstants.STRING)).trim();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* @param nodeName search for nodes with this name
* @param parentNode search in the child nodes of this nodes
* @return text content of the child node or null if no child with the given name was found
*/
public static Node getChild(String nodeName, Node parentNode) {
for (Node child : new NodeListDecorator(parentNode.getChildNodes())) {
if (nodeName.equals(child.getNodeName()))
return child;
}
return null;
}
/**
* Get text content of the first child node matching the given node name. Use this method
* instead of {@link #selectString(String, Object)} whenever xpath support is not required,
* because it is much faster, especially for large documents.
*
* @param nodeName search for nodes with this name
* @param parentNode search in the child nodes of this nodes
* @return text content of the child node or null if no child with the given name was found
*/
public static String getTextContent(String nodeName, Node parentNode) {
Node child = getChild(nodeName, parentNode);
if (child == null)
return null;
return child.getTextContent();
}
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public static int selectInteger(String xpath, Object node) {
return Integer.parseInt(selectString(xpath, node));
}
public static boolean exists(String xpath, Object node) {
return selectNode(xpath, node) != null;
}
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private static XPathExpression getXPath(String xpath) throws XPathExpressionException {
return XPathFactory.newInstance().newXPath().compile(xpath);
}
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/**
* Dummy constructor to prevent instantiation.
*/
private XPathUtilities() {
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throw new UnsupportedOperationException();
}
protected static class NodeListDecorator extends AbstractList<Node> {
private final NodeList nodes;
public NodeListDecorator(NodeList nodes) {
this.nodes = nodes;
}
@Override
public Node get(int index) {
return nodes.item(index);
}
@Override
public int size() {
return nodes.getLength();
}
}
}