XmlReader now uses the SAX API to read XML files into HopObjects. SAX is

generally faster than DOM because it doesn't report an intermediary DOM tree, but
reports parsing events directly to the application.

XmlDatabase now uses a separate, special purpose XmlReader called XmlDatabaseReader
which parses only one-level HopObjects and generates NodeHandle objects
for all references.

src/helma/objectmodel/dom/XmlDatabaseReader.java

@@ -0,0 +1,180 @@
+package helma.objectmodel.dom;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+import java.text.SimpleDateFormat;
+import java.text.ParseException;
+import java.util.Date;
+// import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.List;
+
+import javax.xml.parsers.*;
+
+import org.xml.sax.*;
+import org.xml.sax.helpers.DefaultHandler;
+
+import helma.objectmodel.INode;
+import helma.objectmodel.db.DbKey;
+import helma.objectmodel.db.ExternalizableVector;
+import helma.objectmodel.db.Node;
+import helma.objectmodel.db.NodeHandle;
+import helma.objectmodel.db.NodeManager;
+import helma.objectmodel.db.Property;
+import helma.objectmodel.db.DbMapping;
+
+public final class XmlDatabaseReader extends DefaultHandler implements XmlConstants {
+
+    private NodeManager nmgr = null;
+    private Node currentNode;
+
+    private String elementType = null;
+    private String elementName = null;
+    private StringBuffer charBuffer = null;
+
+    Hashtable propMap = null;
+    List subnodes = null;
+
+    static SAXParserFactory factory = SAXParserFactory.newInstance ();
+
+
+    public XmlDatabaseReader (NodeManager nmgr) {
+	this.nmgr = nmgr;
+    }
+
+
+    /**
+     * read an InputSource with xml-content.
+     */
+    public Node read (File file)
+	throws ParserConfigurationException, SAXException, IOException {
+	if (nmgr==null)
+	    throw new RuntimeException ("can't create a new Node without a NodeManager");
+
+	SAXParser parser = factory.newSAXParser ();
+
+	currentNode = null;
+
+	parser.parse (file, this);
+	return currentNode;
+    }
+
+
+    public void startElement(String namespaceURI, String localName, String qName, Attributes atts) {
+	// System.err.println ("XML-READ: startElement "+namespaceURI+", "+localName+", "+qName+", "+atts.getValue("id"));
+	// discard the first element called xmlroot
+	if ("xmlroot".equals (qName) && currentNode == null)
+	    return;
+	// if currentNode is null, this must be the hopobject node
+	if ("hopobject".equals (qName) && currentNode == null) {
+	    String id = atts.getValue ("id");
+	    String name = atts.getValue ("name");
+	    String prototype = atts.getValue ("prototype");
+	    if ( "".equals(prototype) )
+	        prototype = "hopobject";
+
+	    try {
+	        long created = Long.parseLong (atts.getValue ("created"));
+	        long lastmodified = Long.parseLong (atts.getValue ("lastModified"));
+	        currentNode = new Node (name,id,prototype,nmgr.safe,created,lastmodified);
+	    } catch ( NumberFormatException e ) {
+	        currentNode = new Node (name,id,prototype,nmgr.safe);
+	    }
+	    return;
+	}
+	// find out what kind of element this is by looking at
+	// the number and names of attributes.
+	String idref = atts.getValue ("idref");
+	if (idref != null) {
+	    // a hopobject reference.
+	    NodeHandle handle = makeNodeHandle (atts);
+	    if ("hop:child".equals (qName)) {
+	        if (subnodes == null) {
+	            subnodes = new ExternalizableVector ();
+	            currentNode.setSubnodes (subnodes);
+	        }
+	        subnodes.add (handle);
+	    } else if ("hop:parent".equals (qName)) {
+	        currentNode.setParentHandle (handle);
+	    } else {
+	        Property prop = new Property (qName, currentNode);
+	        prop.setNodeHandle (handle);
+	        if (propMap == null) {
+	            propMap = new Hashtable ();
+	            currentNode.setPropMap (propMap);
+	        }
+	        propMap.put (qName.toLowerCase(), prop);
+	    }
+	} else {
+	    // a primitive property
+	    elementType = atts.getValue ("type");
+	    if (elementType == null)
+	        elementType = "string";
+	    elementName = qName;
+	    if (charBuffer == null)
+	        charBuffer = new StringBuffer();
+	    else
+	        charBuffer.setLength (0);
+	}
+    }
+
+    public void characters (char[] ch, int start, int length)
+                             throws SAXException {
+	// append chars to char buffer
+	if (elementType != null)
+	    charBuffer.append (ch, start, length);
+    }
+
+    public void endElement(String namespaceURI, String localName, String qName)
+                        throws SAXException {
+	if (elementType != null) {
+	    Property prop = new Property (elementName, currentNode);
+	    String charValue = charBuffer.toString ();
+	    charBuffer.setLength (0);
+	    if ( "boolean".equals (elementType) ) {
+	        if ( "true".equals(charValue) ) {
+	            prop.setBooleanValue(true);
+	        } else {
+	            prop.setBooleanValue(false);
+	        }
+	    } else if ( "date".equals(elementType) ) {
+	        SimpleDateFormat format = new SimpleDateFormat ( DATEFORMAT );
+	        try {
+	            Date date = format.parse(charValue);
+	            prop.setDateValue (date);
+	        } catch ( ParseException e ) {
+	            prop.setStringValue (charValue);
+	        }
+	    } else if ( "float".equals(elementType) ) {
+	        prop.setFloatValue ((new Double(charValue)).doubleValue());
+	    } else if ( "integer".equals(elementType) ) {
+	        prop.setIntegerValue ((new Long(charValue)).longValue());
+	    } else {
+	        prop.setStringValue (charValue);
+	    }
+	    if (propMap == null) {
+	        propMap = new Hashtable ();
+	        currentNode.setPropMap (propMap);
+	    }
+	    propMap.put (elementName.toLowerCase(), prop);
+	    elementName = null;
+	    elementType = null;
+	    charValue = null;
+	}
+    }
+
+
+    // create a node handle from a node reference DOM element
+    private NodeHandle makeNodeHandle (Attributes atts) {
+	String idref = atts.getValue ("idref");
+	String protoref = atts.getValue ("prototyperef");
+	DbMapping dbmap = null;
+	if (protoref != null)
+	    dbmap = nmgr.getDbMapping(protoref);
+	return new NodeHandle (new DbKey (dbmap, idref));
+    }
+
+}
+