Source code: com/aendvari/common/model/xalan/XalanModelNode.java

   /*
    * XalanModelNode.java
    *
    * Copyright (c) 2001, 2002 Aendvari, Ltd. All Rights Reserved.
    *
    * See the file LICENSE for terms of use.
    *
    */
   
  package com.aendvari.common.model.xalan;
  
  import java.util.*;
  import java.io.*;
  
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Attr;
  
  import com.aendvari.common.model.*;
  
  
  /**
   * <p>A Xalan XML implementation of the {@link ModelNode} interface.</p>
   *
   * @author  Scott Milne
   *
   */
  
  public class XalanModelNode implements ModelNode
  {
    /* Variables */
  
    /** The owning model tree. */
    protected XalanModelTree owner;
  
    /** The DOM node */
    protected Node modelNode;
  
    /** The node value. */
    protected String modelValue;
  
  
    /* Constructors. */
  
  
    /**
     * Constructs a <code>XalanModelNode</code> instance.
     *
     * @param    setOwner          The owning {@link XalanModelTree}.
     *
     */
  
    protected XalanModelNode(XalanModelTree setOwner)
    {
      owner = setOwner;
  
      modelNode = null;
      modelValue = null;
    }
  
    /**
     * Constructs a <code>XalanModelNode</code> instance wrapping the supplied {@link Node}.
     *
     * @param    setOwner          The owning {@link XalanModelTree}.
     * @param    setModelNode        The XML {@link Node} to wrap.
     *
     */
  
    protected XalanModelNode( XalanModelTree setOwner, Node setModelNode )
    {
      owner = setOwner;
  
      modelNode = setModelNode;
      setXmlValue();
    }
  
  
    /* Accessors. */
  
  
    /**
     * This is used in XalanModelTree::getNode()
     *
     * @param    setOwner          The owning {@link XalanModelTree}.
     *
     */
  
    protected XalanModelNode( XalanModelTree setOwner, String setModelValue )
    {
      owner = setOwner;
  
      modelNode = null;
      modelValue = setModelValue;
    }
  
    /**
     * Sets the internal XML {@link Node} object wrapped by this {@link ModelNode}.
     *
    * @param    setModelNode        The XML {@link Node} to wrap.
    *
    */
 
   public void setXmlNode( Node setModelNode )
   {
     modelNode = setModelNode;
     setXmlValue();
   }
 
   /**
    * Returns the internal XML {@link Node} object wrapped by this {@link ModelNode}.
    *
    * @return                  The XML {@link Node} wrapped by this {@link ModelNode}.
    *
    */
 
   public Node getXmlNode()
   {
     return modelNode;
   }
 
   /**
    * Caches the value of the XML {@link Node}, if any.
    *
    */
 
   protected void setXmlValue()
   {
     // retrieve value from Node
     if (modelNode != null)
     {
       if (modelNode.getNodeValue() != null)
         // get the value directly from the node
         modelValue = modelNode.getNodeValue();
       else
         // get the value from the internal text node
         modelValue = getTextValue();
     }
     else
       modelValue = "";
   }
 
   /**
    * Returns the instance of <code>ModelTree</code> from which the {@link ModelNode} is within.
    *
    * @return                  The {@link ModelTree} instance this node is within.
    *
    */
 
   public ModelTree getOwnerModelTree()
   {
     return owner;
   }
 
   /**
    * Returns the value of the node.
    *
    * @return                  A String value of the node.
    *
    */
 
   public String getNodeValue()
   {
     return modelValue;
   }
 
   /**
    * Returns the text within the node.
    *
    * @return                  The value of the text node within this node.
    *
    */
 
   protected String getTextValue()
   {
     Node node = modelNode.getFirstChild();
 
     // scan for first text node
     while (node != null)
     {
       if (node.getNodeType() == Node.TEXT_NODE)
       {
         return node.getNodeValue();
       }
 
       node = node.getNextSibling();
     }
 
     return "";
   }
 
   /**
    * Sets the value of the node.
    *
    * @param                  A String value for the node.
    *
    */
 
   public void setNodeValue( String value )
   {
     // state DOM modification
     owner.setModified();
 
     // place value into XML Node
     if (modelNode != null)
     {
       modelNode.setNodeValue(value);
     }
 
     // place value into node string
     if (value == null)
       modelValue = "";
     else
       modelValue = value;
   }
 
   /**
    * Returns the name of this node.
    *
    * @return                  The name of this node.
    *
    */
 
   public String getNodeName()
   {
     return modelNode.getNodeName();
   }
 
   /**
    * Returns a string representation of the node's position in the hierarchy.
    *
    * @return                  The position of this node in the hierarchy.
    *
    */
 
   public String getNodePath()
   {
     LinkedList nodes = new LinkedList();
 
     // traverse node tree upwards, and collect the nodes
     Node node = modelNode;
 
     do
     {
       nodes.addFirst(node);
       node = node.getParentNode();
     }
     while (node != null);
 
     // traverse back down tree, and create topic path
     Iterator nodeIterator = nodes.iterator();
     StringBuffer path = new StringBuffer();
 
     // skip the root node
     nodeIterator.next();
 
     while (nodeIterator.hasNext())
     {
       // get the node at this level
       node = (Node)nodeIterator.next();
 
       path.append('/');
       path.append(node.getNodeName());
     }
 
     return path.toString();
   }
 
   /**
    * Returns the attributes of this node.
    *
    * @return                  A <code>Map</code> of all attibutes.
    *
    */
 
   public Map getAttributes()
   {
     HashMap attributes = new HashMap();
     NamedNodeMap nodeMap = modelNode.getAttributes();
 
     if (nodeMap != null)
     {
       int count = nodeMap.getLength();
       int index;
 
       // extract each attribute node
       for (index = 0; index < count; index++)
       {
         Node attribute = nodeMap.item(index);
 
         // add attribute to output map
         attributes.put(attribute.getNodeName(), attribute.getNodeValue());
       }
     }
 
     return attributes;
   }
 
   /**
    * Returns the string value of the specified attribute.
    *
    * @param                  The name of the attribute.
    *
    * @return                  The string of the attribute.
    *
    */
 
   public String getAttribute( String name )
   {
     NamedNodeMap nodeMap = modelNode.getAttributes();
     if( nodeMap != null )
     {
       Node attribute = nodeMap.getNamedItem(name);
       if( attribute != null )
       {
         return attribute.getFirstChild().getNodeValue();
       }
     }
 
     return "";
   }
 
   /**
    * Sets the string value of the attribute.
    *
    * @param    name            The name of the attribute.
    * @param    value            The value of the attribute.
    *
    */
 
   public void setAttribute( String name, String value )
   {
     // state DOM modification
     owner.setModified();
 
     // retrieve and update attribute
     NamedNodeMap nodeMap = modelNode.getAttributes();
 
     Attr attribute = modelNode.getOwnerDocument().createAttribute(name);
     attribute.setValue(value);
 
     nodeMap.setNamedItem(attribute);
   }
 
 
   /* Node access. */
 
 
   /**
    * The parent of this node. All nodes, except the root ({@link ModelNode})
    * node may have a parent. If a node has just been created and not yet added to the tree, or if
    * it has been removed from the tree, this is null.
    *
    * @return                  The parent of this node.
    *
    */
 
   public ModelNode getParentNode()
   {
     Node parentNode = modelNode.getParentNode();
 
     if( parentNode != null )
     {
       return new XalanModelNode(owner, parentNode);
     }
 
     return null;
   }
 
   /**
    * The first child of this node. If there is no such node, this returns null.
    *
    * @return                  The first child node.
    *
    */
 
   public ModelNode getFirstChild()
   {
     Node node = modelNode.getFirstChild();
 
     if( node != null )
     {
       return new XalanModelNode(owner, node);
     }
 
     return null;
   }
 
   /**
    * The last child of this node. If there is no such node, this returns null.
    *
    * @return                  The last child node.
    *
    */
 
   public ModelNode getLastChild()
   {
     Node node = modelNode.getLastChild();
 
     if( node != null )
     {
       return new XalanModelNode(owner, node);
     }
 
     return null;
   }
 
   /**
    * The node immediately preceding this node. If there is no such node,
    * this returns null.
    *
    * @return                  The preceding sibling node.
    *
    */
 
   public ModelNode getPreviousSibling()
   {
     Node node = modelNode.getPreviousSibling();
 
     if( node != null )
     {
       return new XalanModelNode(owner, node);
     }
 
     return null;
   }
 
   /**
    * The node immediately following this node. If there is no such node,
    * this returns null.
    *
    * @return                  The following sibling node.
    *
    */
 
   public ModelNode getNextSibling()
   {
     Node node = modelNode.getNextSibling();
 
     if( node != null )
     {
       return new XalanModelNode(owner, node);
     }
 
     return null;
   }
 
   /**
    * Returns a <code>List</code> of {@link ModelNode}'s using the path provided.
    *
    * @return                  A <code>List</code> of this nodes' children as {@link ModelNode}'s.
    *
    */
 
   public List getChildNodes()
   {
     ArrayList xmlNodeList = new ArrayList();
 
     Node tmpNode = modelNode.getFirstChild();
 
     while (tmpNode != null)
     {
       xmlNodeList.add( new XalanModelNode(owner, tmpNode) );
       tmpNode = tmpNode.getNextSibling();
     }
 
     return xmlNodeList;
   }
 
   /**
    * Returns whether this node has any children.
    *
    * @return                  True if this node has children, false otherwise.
    *
    */
 
   public boolean hasChildNodes()
   {
     return modelNode.hasChildNodes();
   }
 
 
   /* Node manipulation. */
 
 
   /**
    * Adds the node <code>newChild</code> to the end of the list of children of this node.
    * If the <code>newChild</code> is already in the tree, it is first removed.
    *
    * @param    newChild          The node to add.
    *
    * @return                  The node added.
    *
    */
 
   public ModelNode appendChild(ModelNode newChild)
   {
     // state DOM modification
     owner.setModified();
 
     // append node
     Node childNode = ((XalanModelNode)newChild).getXmlNode();
     Node node = modelNode.appendChild(childNode);
     return new XalanModelNode(owner, node);
   }
 
   /**
    * Inserts the node <code>newChild</code> before the existing child node <code>refChild</code>.
    * If <code>refChild</code> is null, <code>newChild</code> is inserted at the end of the list
    * of children. If the <code>newChild</code> is already in the tree, it is first removed.
    *
    * @param    newChild          The node to insert.
    * @param    refChild          The reference node.
    *
    * @return                  The node inserted.
    *
    */
 
   public ModelNode insertBefore(ModelNode newChild, ModelNode refChild)
   {
     // state DOM modification
     owner.setModified();
 
     // insert node
     Node xNewChild = ((XalanModelNode)newChild).getXmlNode();
     Node xRefChild = ((XalanModelNode)refChild).getXmlNode();
 
     Node node = modelNode.insertBefore(xNewChild, xRefChild);
     return new XalanModelNode(owner, node);
   }
 
   /**
    * Replaces the child node <code>oldChild</code> with <code>newChild</code>, and returns
    * the <code>oldChild</code> node. If the <code>newChild</code> is already in the tree,
    * it is first removed.
    *
    * @param    newChild          The node to replace.
    * @param    oldChild          The node being replaced.
    *
    * @return                  The node replaced.
    *
    */
 
   public ModelNode replaceChild(ModelNode newChild, ModelNode oldChild)
   {
     // state DOM modification
     owner.setModified();
 
     // replaceNode
     Node xNewChild = ((XalanModelNode)newChild).getXmlNode();
     Node xOldChild = ((XalanModelNode)oldChild).getXmlNode();
 
     Node node = modelNode.replaceChild(xNewChild, xOldChild);
     return new XalanModelNode(owner, node);
   }
 
   /**
    * Removes the child node indicated by <code>oldChild</code> from the list of children,
    * and returns it.
    *
    * @param    oldChild          The node to remove.
    *
    * @return                  The removed node.
    *
    */
 
   public ModelNode removeChild(ModelNode oldChild)
   {
     // state DOM modification
     owner.setModified();
 
     // remove node
     Node xOldNode = ((XalanModelNode)oldChild).getXmlNode();
     Node node = modelNode.removeChild(xOldNode);
     return new XalanModelNode(owner, node);
   }
 
   /**
    * Display the string value of the node.
    *
    */
 
   public String toString()
   {
     StringBuffer buffer = new StringBuffer();
 
     if (modelNode != null)
     {
       buffer.append("name=");
       buffer.append(getNodeName());
       buffer.append("; ");
     }
 
     buffer.append("value=" + modelValue);
 
     if (modelNode != null)
     {
       buffer.append("; node=");
       buffer.append(modelNode.toString());
     }
 
     return buffer.toString();
   }
 }