NodeHelper.java :  » XML » dom4j-2.0.0 » org » dom4j » Java Open Source

/////////////////////////////////////////////////////////////////////////////
// $Id$  
package org.dom4j;

import org.dom4j.tree.BackedList;

import java.util.EnumSet;

/**
 * @author Jirsk Filip
 * @version $Revision$
 */
public final class NodeHelper {

  private static final EnumSet<NodeType> BRANCH_TYPE = EnumSet.of(NodeType.ELEMENT_NODE, NodeType.DOCUMENT_NODE);

  private NodeHelper() {
  }

  public static Attribute nodeAsAttribute(Node node) {
    if (node.getNodeTypeEnum() == NodeType.ATTRIBUTE_NODE) {
      assert node instanceof Attribute;
      return (Attribute) node;
    }
    return null;
  }

  public static Branch nodeAsBranch(Node node) {
    if (BRANCH_TYPE.contains(node.getNodeType())) {
      assert node instanceof Branch;
      return (Branch) node;
    }
    return null;
  }

  public static Document nodeAsDocument(Node node) {
    if (node.getNodeTypeEnum() == NodeType.DOCUMENT_NODE) {
      assert node instanceof Document;
      return (Document) node;
    }
    return null;
  }

  /**
   * If node type is element, returns node typed as <code>Element</code>, or <code>null</code> otherwise.
   * @param node
   * @return Element node or <code>null</code>
   */
  public static Element nodeAsElement(Node node) {
    if (node.getNodeTypeEnum() == NodeType.ELEMENT_NODE) {
      assert node instanceof Element;
      return (Element) node;
    }
    return null;
  }

  public static Namespace nodeAsNamespace(Node node) {
    if (node.getNodeTypeEnum() == NodeType.NAMESPACE_NODE) {
      assert node instanceof Namespace;
      return (Namespace) node;
    }
    return null;
  }

  public static ProcessingInstruction nodeAsProcessingInstruction(Node node) {
    if (node.getNodeTypeEnum() == NodeType.PROCESSING_INSTRUCTION_NODE) {
      assert node instanceof ProcessingInstruction;
      return (ProcessingInstruction) node;
    }
    return null;
  }

  public static BackedList<Element> appendElementLocal(Node node, BackedList<Element> list) {
    Element element = nodeAsElement(node);
    if (element != null) {
      list.addLocal(element);
    }

    return list;
  }

  public static BackedList<Element> appendElementNamedLocal(Node node, BackedList<Element> list, String name) {
    Element element = nodeAsElement(node);
    if (element != null && name.equals(element.getName())) {
      list.addLocal(element);
    }

    return list;
  }

  public static BackedList<Element> appendElementQNamedLocal(Node node, BackedList<Element> list, QName qname) {
    Element element = nodeAsElement(node);
    if (element != null && qname.equals(element.getQName())) {
      list.addLocal(element);
    }

    return list;
  }

  public static String getAttributeValue(Attribute attribute, String defaultValue) {
    return attribute == null ? defaultValue : attribute.getValue();
  }
}