dtmdefaultbase.java

来自「java jdk 1.4的源码」· Java 代码 · 共 2,022 行 · 第 1/5 页

        case DTM.ENTITY_NODE :
          typestring = "ENTITY";
          break;
        case DTM.ENTITY_REFERENCE_NODE :
          typestring = "ENT_REF";
          break;
        case DTM.NAMESPACE_NODE :
          typestring = "NAMESPACE";
          break;
        case DTM.NOTATION_NODE :
          typestring = "NOTATION";
          break;
        case DTM.NULL :
          typestring = "null";
          break;
        case DTM.PROCESSING_INSTRUCTION_NODE :
          typestring = "PI";
          break;
        case DTM.TEXT_NODE :
          typestring = "TEXT";
          break;
        default :
          typestring = "Unknown!";
          break;
        }

      StringBuffer sb=new StringBuffer();
	  sb.append("["+nodeHandle+": "+typestring+
				"(0x"+Integer.toHexString(getExpandedTypeID(nodeHandle))+") "+
				getNodeNameX(nodeHandle)+" {"+getNamespaceURI(nodeHandle)+"}"+
				"=\""+ getNodeValue(nodeHandle)+"\"]");
	  return sb.toString();
  }

  // ========= DTM Implementation Control Functions. ==============

  /**
   * Set an implementation dependent feature.
   * <p>
   * %REVIEW% Do we really expect to set features on DTMs?
   *
   * @param featureId A feature URL.
   * @param state true if this feature should be on, false otherwise.
   */
  public void setFeature(String featureId, boolean state){}

  // ========= Document Navigation Functions =========

  /**
   * Given a node handle, test if it has child nodes.
   * <p> %REVIEW% This is obviously useful at the DOM layer, where it
   * would permit testing this without having to create a proxy
   * node. It's less useful in the DTM API, where
   * (dtm.getFirstChild(nodeHandle)!=DTM.NULL) is just as fast and
   * almost as self-evident. But it's a convenience, and eases porting
   * of DOM code to DTM.  </p>
   *
   * @param nodeHandle int Handle of the node.
   * @return int true if the given node has child nodes.
   */
  public boolean hasChildNodes(int nodeHandle)
  {

    int identity = makeNodeIdentity(nodeHandle);
    int firstChild = _firstch(identity);

    return firstChild != DTM.NULL;
  }
	
  /** Given a node identity, return a node handle. If extended addressing
   * has been used (multiple DTM IDs), we need to map the high bits of the
   * identity into the proper DTM ID.
   * 
   * This has been made FINAL to facilitate inlining, since we do not expect
   * any subclass of DTMDefaultBase to ever change the algorithm. (I don't
   * really like doing so, and would love to have an excuse not to...)
   * 
   * %REVIEW% Is it worth trying to specialcase small documents?
   * %REVIEW% Should this be exposed at the package/public layers?
   * 
   * @param nodeIdentity Internal offset to this node's records.
   * @return NodeHandle (external representation of node)
   * */
  final protected int makeNodeHandle(int nodeIdentity)
  {
    if(NULL==nodeIdentity) return NULL;
		
    if(JJK_DEBUG && nodeIdentity>DTMManager.IDENT_NODE_DEFAULT)
      System.err.println("GONK! (only useful in limited situations)");

    return m_dtmIdent.elementAt(nodeIdentity >>> DTMManager.IDENT_DTM_NODE_BITS)
      + (nodeIdentity & DTMManager.IDENT_NODE_DEFAULT) ;											
  }
	
  /** Given a node handle, return a node identity. If extended addressing
   * has been used (multiple DTM IDs), we need to map the high bits of the
   * identity into the proper DTM ID and thence find the proper offset
   * to add to the low bits of the identity
   * 
   * This has been made FINAL to facilitate inlining, since we do not expect
   * any subclass of DTMDefaultBase to ever change the algorithm. (I don't
   * really like doing so, and would love to have an excuse not to...)
   * 
   * %OPT% Performance is critical for this operation.
   *
   * %REVIEW% Should this be exposed at the package/public layers?
   * 
   * @param NodeHandle (external representation of node)
   * @return nodeIdentity Internal offset to this node's records.
   * */
  final protected int makeNodeIdentity(int nodeHandle)
  {
    if(NULL==nodeHandle) return NULL;

    if(m_mgrDefault!=null)
    {
      // Optimization: use the DTMManagerDefault's fast DTMID-to-offsets
      // table.  I'm not wild about this solution but this operation
      // needs need extreme speed.

      int whichDTMindex=nodeHandle>>>DTMManager.IDENT_DTM_NODE_BITS;

      // %REVIEW% Wish I didn't have to perform the pre-test, but
      // someone is apparently asking DTMs whether they contain nodes
      // which really don't belong to them. That's probably a bug
      // which should be fixed, but until it is:
      if(m_mgrDefault.m_dtms[whichDTMindex]!=this)
	return NULL;
      else
	return
	  m_mgrDefault.m_dtm_offsets[whichDTMindex]
	  | (nodeHandle & DTMManager.IDENT_NODE_DEFAULT);
    }
	  
    int whichDTMid=m_dtmIdent.indexOf(nodeHandle & DTMManager.IDENT_DTM_DEFAULT);
    return (whichDTMid==NULL) 
      ? NULL
      : (whichDTMid << DTMManager.IDENT_DTM_NODE_BITS)
      + (nodeHandle & DTMManager.IDENT_NODE_DEFAULT);
  }


  /**
   * Given a node handle, get the handle of the node's first child.
   * If not yet resolved, waits for more nodes to be added to the document and
   * tries again.
   *
   * @param nodeHandle int Handle of the node.
   * @return int DTM node-number of first child, or DTM.NULL to indicate none exists.
   */
  public int getFirstChild(int nodeHandle)
  {

    int identity = makeNodeIdentity(nodeHandle);
    int firstChild = _firstch(identity);

    return makeNodeHandle(firstChild);
  }

  /**
   * Given a node handle, advance to its last child.
   * If not yet resolved, waits for more nodes to be added to the document and
   * tries again.
   *
   * @param nodeHandle int Handle of the node.
   * @return int Node-number of last child,
   * or DTM.NULL to indicate none exists.
   */
  public int getLastChild(int nodeHandle)
  {

    int identity = makeNodeIdentity(nodeHandle);
    int child = _firstch(identity);
    int lastChild = DTM.NULL;

    while (child != DTM.NULL)
    {
      lastChild = child;
      child = _nextsib(child);
    }

    return makeNodeHandle(lastChild);
  }

  /**
   * Retrieves an attribute node by by qualified name and namespace URI.
   *
   * @param nodeHandle int Handle of the node upon which to look up this attribute..
   * @param namespaceURI The namespace URI of the attribute to
   *   retrieve, or null.
   * @param name The local name of the attribute to
   *   retrieve.
   * @return The attribute node handle with the specified name (
   *   <code>nodeName</code>) or <code>DTM.NULL</code> if there is no such
   *   attribute.
   */
  public abstract int getAttributeNode(int nodeHandle, String namespaceURI,
                                       String name);

  /**
   * Given a node handle, get the index of the node's first attribute.
   *
   * @param nodeHandle int Handle of the node.
   * @return Handle of first attribute, or DTM.NULL to indicate none exists.
   */
  public int getFirstAttribute(int nodeHandle)
  {

    int type = getNodeType(nodeHandle);

    if (DTM.ELEMENT_NODE == type)
    {

      // Assume that attributes and namespaces immediately follow the element.
      int identity = makeNodeIdentity(nodeHandle);

      while (DTM.NULL != (identity = getNextNodeIdentity(identity)))
      {

        // Assume this can not be null.
        type = _type(identity);

        if (type == DTM.ATTRIBUTE_NODE)
        {
          return makeNodeHandle(identity);
        }
        else if (DTM.NAMESPACE_NODE != type)
        {
          break;
        }
      }
    }

    return DTM.NULL;
  }

  /**
   * Given a node handle, advance to its next sibling.
   * If not yet resolved, waits for more nodes to be added to the document and
   * tries again.
   * @param nodeHandle int Handle of the node.
   * @return int Node-number of next sibling,
   * or DTM.NULL to indicate none exists.
   */
  public int getNextSibling(int nodeHandle)
  {
    return makeNodeHandle(_nextsib(makeNodeIdentity(nodeHandle)));
  }

  /**
   * Given a node handle, find its preceeding sibling.
   * WARNING: DTM is asymmetric; this operation is resolved by search, and is
   * relatively expensive.
   *
   * @param nodeHandle the id of the node.
   * @return int Node-number of the previous sib,
   * or DTM.NULL to indicate none exists.
   */
  public int getPreviousSibling(int nodeHandle)
  {
    return makeNodeHandle(_prevsib(makeNodeIdentity(nodeHandle)));
  }

  /**
   * Given a node handle, advance to the next attribute.
   * If an attr, we advance to
   * the next attr on the same node.  If not an attribute, we return NULL.
   *
   * @param nodeHandle int Handle of the node.
   * @return int DTM node-number of the resolved attr,
   * or DTM.NULL to indicate none exists.
   */
  public int getNextAttribute(int nodeHandle)
  {

    int type = getNodeType(nodeHandle);

    if (DTM.ATTRIBUTE_NODE == type)
    {
      // Assume that attributes and namespace nodes immediately follow the element.
      int identity = makeNodeIdentity(nodeHandle);

      while (DTM.NULL != (identity = getNextNodeIdentity(identity)))
      {
        type = _type(identity);

        if (type == DTM.ATTRIBUTE_NODE)
        {
          return makeNodeHandle(identity);
        }
        else if (type != DTM.NAMESPACE_NODE)
        {
          break;
        }
      }
    }

    return DTM.NULL;
  }

  /** Lazily created namespace lists. */
  private Vector m_namespaceLists = null;  // on demand


  /** Build table of namespace declaration
   * locations during DTM construction. Table is a Vector of
   * SuballocatedIntVectors containing the namespace node HANDLES declared at
   * that ID, plus an SuballocatedIntVector of the element node INDEXES at which
   * these declarations appeared.
   *
   * NOTE: Since this occurs during model build, nodes will be encountered
   * in doucment order and thus the table will be ordered by element,
   * permitting binary-search as a possible retrieval optimization.
   *
   * %REVIEW% Directly managed arrays rather than vectors?
   * %REVIEW% Handles or IDs? Given usage, I think handles.
   * */
  protected void declareNamespaceInContext(int elementNodeIndex,int namespaceNodeIndex)
  {
    SuballocatedIntVector nsList=null;
    if(m_namespaceDeclSets==null)
      {

        // First
        m_namespaceDeclSetElements=new SuballocatedIntVector();
        m_namespaceDeclSetElements.addElement(elementNodeIndex);
        m_namespaceDeclSets=new Vector();
        nsList=new SuballocatedIntVector();
        m_namespaceDeclSets.addElement(nsList);
      }
    else
      {
        // Most recent. May be -1 (none) if DTM was pruned.
        // %OPT% Is there a lastElement() method? Should there be?
        int last=m_namespaceDeclSetElements.size()-1;
	        
        if(last>=0 && elementNodeIndex==m_namespaceDeclSetElements.elementAt(last))
          {
            nsList=(SuballocatedIntVector)m_namespaceDeclSets.elementAt(last);
          }
      }
    if(nsList==null)
      {
        m_namespaceDeclSetElements.addElement(elementNodeIndex);
        nsList=new SuballocatedIntVector();
        m_namespaceDeclSets.addElement(nsList);

        SuballocatedIntVector inherited= findNamespaceContext(_parent(elementNodeIndex));

        if(inherited!=null)
          {
            // %OPT% Count-down might be faster, but debuggability may
            // be better this way, and if we ever decide we want to
            // keep this ordered by expanded-type...
            int isize=inherited.size();
            for(int i=0;i<isize;++i)
              {
                nsList.addElement(inherited.elementAt(i));
              }
          }
      }

    // Handle overwriting inherited.
    // %OPT% Keep sorted? (By expanded-name rather than by doc order...)
    // Downside: Would require insertElementAt if not found,
    // which has recopying costs. But these are generally short lists...
    int newEType=_exptype(namespaceNodeIndex);

    for(int i=nsList.size()-1;i>=0;--i)
      {
        if(newEType==getExpandedTypeID(nsList.elementAt(i)))
          {
            nsList.setElementAt(makeNodeHandle(namespaceNodeIndex),i);
            return;
          }
      }
    nsList.addElement(makeNodeHandle(namespaceNodeIndex));
  }

  /** Retrieve list of namespace declaration locations
     * active at this node. List is an SuballocatedIntVector whose
     * entries are the namespace node HANDLES declared at that ID.
     *
     * %REVIEW% Directly managed arrays rather than vectors?
     * %REVIEW% Handles or IDs? Given usage, I think handles.
     * */
  protected SuballocatedIntVector findNamespaceContext(int elementNodeIndex)
  {
    if (null!=m_namespaceDeclSetElements)
      {
        // %OPT% Is binary-search really saving us a lot versus linear?
        // (... It may be, in large docs with many NS decls.)
        int wouldBeAt=findInSortedSuballocatedIntVector(m_namespaceDeclSetElements,
                                            elementNodeIndex);
        if(wouldBeAt>=0) // Found it
          return (SuballocatedIntVector) m_namespaceDeclSets.elementAt(wouldBeAt);
        if(wouldBeAt == -1) // -1-wouldbeat == 0
          return null; // Not after anything; definitely not found

        // Not found, but we know where it should have been.
        // Search back until we find an ancestor or run out.
        wouldBeAt=-1-wouldBeAt;

        // Decrement wouldBeAt to find last possible ancestor
        int candidate=m_namespaceDeclSetElements.elementAt(-- wouldBeAt);