DomEcho06.java
/* * @(#)DomEcho06.java 1.9 98/11/10 * * */ import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.FactoryConfigurationError; import javax.xml.parsers.ParserConfigurationException; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import java.io.File; import java.io.IOException; import org.w3c.dom.Document; import org.w3c.dom.DOMException; import org.w3c.dom.Element; import org.w3c.dom.Node; // Basic GUI components import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTree; // GUI components for right-hand side import javax.swing.JSplitPane; import javax.swing.JEditorPane; // GUI support classes import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Toolkit; import java.awt.event.WindowEvent; import java.awt.event.WindowAdapter; // For creating borders import javax.swing.border.EmptyBorder; import javax.swing.border.BevelBorder; import javax.swing.border.CompoundBorder; // For creating a TreeModel import javax.swing.tree.*; import javax.swing.event.*; import java.util.*; public class DomEcho06 extends JPanel { // Global value so it can be ref'd by the tree-adapter static Document document; boolean compress = false; static final int windowHeight = 460; static final int leftWidth = 300; static final int rightWidth = 340; static final int windowWidth = leftWidth + rightWidth; public DomEcho06() { // Make a nice border EmptyBorder eb = new EmptyBorder(5,5,5,5); BevelBorder bb = new BevelBorder(BevelBorder.LOWERED); CompoundBorder cb = new CompoundBorder(eb,bb); this.setBorder(new CompoundBorder(cb,eb)); // Set up the tree JTree tree = new JTree(new DomToTreeModelAdapter()); // Iterate over the tree and make nodes visible // (Otherwise, the tree shows up fully collapsed) // TreePath nodePath = ???; // tree.expandPath(nodePath); // Build left-side view JScrollPane treeView = new JScrollPane(tree); treeView.setPreferredSize(new Dimension( leftWidth, windowHeight )); // Build right-side view // (must be final to be referenced in inner class) final JEditorPane htmlPane = new JEditorPane("text/html",""); htmlPane.setEditable(false); JScrollPane htmlView = new JScrollPane(htmlPane); htmlView.setPreferredSize(new Dimension( rightWidth, windowHeight )); // Wire the two views together. Use a selection listener // created with an anonymous inner-class adapter. tree.addTreeSelectionListener ( new TreeSelectionListener() { public void valueChanged(TreeSelectionEvent e) { TreePath p = e.getNewLeadSelectionPath(); if (p != null) { AdapterNode adpNode = (AdapterNode) p.getLastPathComponent(); htmlPane.setText(adpNode.content()); } } } ); // Build split-pane view JSplitPane splitPane = new JSplitPane( JSplitPane.HORIZONTAL_SPLIT, treeView, htmlView ); splitPane.setContinuousLayout( true ); splitPane.setDividerLocation( leftWidth ); splitPane.setPreferredSize( new Dimension( windowWidth + 10, windowHeight+10 )); // Add GUI components this.setLayout(new BorderLayout()); this.add("Center", splitPane ); } // constructor public static void main String(argv[]) { if (argv.length != 1) { buildDom(); makeFrame(); return; } DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //factory.setValidating(true); //factory.setNamespaceAware(true); try { DocumentBuilder builder = factory.newDocumentBuilder(); document = builder.parse( new File(argv[0]) ); makeFrame(); } catch SAXParseException(spe) { // Error generated by the parser System.out.println("\n** Parsing error" + ", line " + spe.getLineNumber() + ", uri " + spe.getSystemId()); System.out.println(" " + spe.getMessage() ); // Use the contained exception, if any Exception x = spe; if (spe.getException() != null) x = spe.getException(); x.printStackTrace(); } catch SAXException(sxe) { // Error generated during parsing) Exception x = sxe; if (sxe.getException() != null) x = sxe.getException(); x.printStackTrace(); } catch ParserConfigurationException(pce) { // Parser with specified options can't be built pce.printStackTrace(); } catch IOException(ioe) { // I/O error ioe.printStackTrace(); } } // main public static void makeFrame() { // Set up a GUI framework JFrame frame = new JFrame("DOM Echo"); frame.addWindowListener ( new WindowAdapter() { public void windowClosing(WindowEvent e) {System.exit(0);} } ); // Set up the tree, the views, and display it all final DomEcho06 echoPanel = new DomEcho06(); frame.getContentPane().add("Center", echoPanel ); frame.pack(); Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); int w = windowWidth + 10; int h = windowHeight + 10; frame.setLocation(screenSize.width/3 - w/2, screenSize.height/2 - h/2); frame.setSize(w, h); frame.setVisible(true); } // makeFrame public static void buildDom() { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); try { DocumentBuilder builder = factory.newDocumentBuilder(); document = builder.newDocument(); // Create from whole cloth Element root = (Element) document.createElement("rootElement"); document.appendChild(root); root.appendChild( document.createTextNode("Some") ); root.appendChild( document.createTextNode(" ") ); root.appendChild( document.createTextNode("text") ); // normalize text representation // getDocumentElement() returns the document's root node document.getDocumentElement().normalize(); } catch ParserConfigurationException(pce) { // Parser with specified options can't be built pce.printStackTrace(); } } // buildDom // An array of names for DOM node-types // Array(indexes = nodeType() values.) static final String[] typeName = { "none", "Element", "Attr", "Text", "CDATA", "EntityRef", "Entity", "ProcInstr", "Comment", "Document", "DocType", "DocFragment", "Notation", }; static final int ELEMENT_TYPE = Node.ELEMENT_NODE; static final int ATTR_TYPE = Node.ATTRIBUTE_NODE; static final int TEXT_TYPE = Node.TEXT_NODE; static final int CDATA_TYPE = Node.CDATA_SECTION_NODE; static final int ENTITYREF_TYPE = Node.ENTITY_REFERENCE_NODE; static final int ENTITY_TYPE = Node.ENTITY_NODE; static final int PROCINSTR_TYPE = Node.PROCESSING_INSTRUCTION_NODE; static final int COMMENT_TYPE = Node.COMMENT_NODE; static final int DOCUMENT_TYPE = Node.DOCUMENT_NODE; static final int DOCTYPE_TYPE = Node.DOCUMENT_TYPE_NODE; static final int DOCFRAG_TYPE = Node.DOCUMENT_FRAGMENT_NODE; static final int NOTATION_TYPE = Node.NOTATION_NODE; // The list of elements to display in the tree // Could set this with a command-line argument, but // not much point -- the list of tree elements still // has to be defined internally. // Extra credit: Read the list from a file // Super-extra credit: Process a DTD and build the list. static String[] treeElementNames = { "slideshow", "slide", "title", // For slideshow #1 "slide-title", // For slideshow #10 "item", }; boolean treeElement String(elementName) { for (int i=0; i<treeElementNames.length; i++) { if ( elementName.equals(treeElementNames[i]) ) return true; } return false; } // This class wraps a DOM node and returns the text we want to // display in the tree. It also returns children, index values, // and child counts. public class AdapterNode { org.w3c.dom.Node domNode; // Construct an Adapter node from a DOM node public AdapterNode(org.w3c.dom.Node node) { domNode = node; } // Return a string that identifies this node in the tree public String toString() { String s = typeName[domNode.getNodeType()]; String nodeName = domNode.getNodeName(); if (! nodeName.startsWith("#")) { s += ": " + nodeName; } if (compress) { String t = content().trim(); int x = t.indexOf("\n"); if (x >= 0) t = t.substring(0, x); s += " " + t; return s; } if (domNode.getNodeValue() != null) { if (s.startsWith("ProcInstr")) s += ", "; else s += ": "; // Trim the value to get rid of NL's at the front String t = domNode.getNodeValue().trim(); int x = t.indexOf("\n"); if (x >= 0) t = t.substring(0, x); s += t; } return s; } public String content() { String s = ""; org.w3c.dom.NodeList nodeList = domNode.getChildNodes(); for (int i=0; i<nodeList.getLength(); i++) { org.w3c.dom.Node node = nodeList.item(i); int type = node.getNodeType(); AdapterNode adpNode = new AdapterNode(node); //inefficient, but works if (type == ELEMENT_TYPE) { // Skip subelements that are displayed in the tree. if ( treeElement(node.getNodeName()) ) continue; // EXTRA-CREDIT HOMEWORK: // Special case the SLIDE element to use the TITLE text // and ignore TITLE element when constructing the tree. // EXTRA-CREDIT // Convert ITEM elements to html lists using // <ul>, <li>, </ul> tags s += "<" + node.getNodeName() + ">"; s += adpNode.content(); s += "</" + node.getNodeName() + ">"; } else if (type == TEXT_TYPE) { s += node.getNodeValue(); } else if (type == ENTITYREF_TYPE) { // The content is in the TEXT node under it s += adpNode.content(); } else if (type == CDATA_TYPE) { // The "value" has the text, same as a text node. // while EntityRef has it in a text node underneath. // (because EntityRef can contain multiple subelements) // Convert angle brackets and ampersands for display StringBuffer sb = new StringBuffer( node.getNodeValue() ); for (int j=0; j<sb.length(); j++) { if (sb.charAt(j) == '<') { sb.setCharAt(j, '&'); sb.insert(j+1, "lt;"); j += 3; } else if (sb.charAt(j) == '&') { sb.setCharAt(j, '&'); sb.insert(j+1, "amp;"); j += 4; } } s += "<pre>" + sb + "\n</pre>"; } // Ignoring these: // ATTR_TYPE -- not in the DOM tree // ENTITY_TYPE -- does not appear in the DOM // PROCINSTR_TYPE -- not "data" // COMMENT_TYPE -- not "data" // DOCUMENT_TYPE -- Root node only. No data to display. // DOCTYPE_TYPE -- Appears under the root only // DOCFRAG_TYPE -- equiv. to "document" for fragments // NOTATION_TYPE -- nothing but binary data in here } return s; } /* * Return children, index, and count values */ public int index(AdapterNode child) { //System.err.println("Looking for index of " + child); int count = childCount(); for (int i=0; i<count; i++) { AdapterNode n = this.child(i); if (child.domNode == n.domNode) return i; } return -1; // Should never get here. } public AdapterNode child(int searchIndex) { //Note: JTree index is zero-based. org.w3c.dom.Node node = domNode.getChildNodes().item(searchIndex); if (compress) { // Return Nth displayable node int elementNodeIndex = 0; for (int i=0; i<domNode.getChildNodes().getLength(); i++) { node = domNode.getChildNodes().item(i); if (node.getNodeType() == ELEMENT_TYPE && treeElement( node.getNodeName() ) && elementNodeIndex++ == searchIndex) { break; } } } return new AdapterNode(node); } public int childCount() { if (!compress) { // Indent this return domNode.getChildNodes().getLength(); } int count = 0; for (int i=0; i<domNode.getChildNodes().getLength(); i++) { org.w3c.dom.Node node = domNode.getChildNodes().item(i); if (node.getNodeType() == ELEMENT_TYPE && treeElement( node.getNodeName() )) { // Note: // Have to check for proper type. // The DOCTYPE element also has the right name ++count; } } return count; } } // This adapter converts the current Document (a DOM) into // a JTree model. public class DomToTreeModelAdapter implements javax.swing.tree.TreeModel { // Basic TreeModel operations public Object getRoot() { //System.err.println("Returning root: " +document); return new AdapterNode(document); } public boolean isLeaf Object(aNode) { // Determines whether the icon shows up to the left. // Return true for any node with no children AdapterNode node = (AdapterNode) aNode; if (node.childCount() > 0) return false; return true; } public int getChildCount Object(parent) { AdapterNode node = (AdapterNode) parent; return node.childCount(); } public Object getChild Object(parent, int index) { AdapterNode node = (AdapterNode) parent; return node.child(index); } public int getIndexOfChild Object(parent, Object child) { AdapterNode node = (AdapterNode) parent; return node.index((AdapterNode) child); } public void valueForPathChanged(TreePath path, Object newValue) { // Null. We won't be making changes in the GUI // If we did, we would ensure the new value was really new, // adjust the model, and then fire a TreeNodesChanged event. } /* * Use these methods to add and remove event listeners. * (Needed to satisfy TreeModel interface, but not used.) */ private Vector listenerList = new Vector(); public void addTreeModelListener(TreeModelListener listener) { if ( listener != null && ! listenerList.contains( listener ) ) { listenerList.addElement( listener ); } } public void removeTreeModelListener(TreeModelListener listener) { if ( listener != null ) { listenerList.removeElement( listener ); } } // Note: Since XML works with 1.1, this example uses Vector. // If coding for 1.2 or later, though, I'd use this instead: // private List listenerList = new LinkedList(); // The operations on the List are then add(), remove() and // iteration, via: // Iterator it = listenerList.iterator(); // while ( it.hasNext() ) // { // TreeModelListener listener = (TreeModelListener) it.next(); // ... // } /* * Invoke these methods to inform listeners of changes. * (Not needed for this example.) * Methods taken from TreeModelSupport class described at * http://java.sun.com/products/jfc/tsc/articles/jtree/index.html * That architecture (produced by Tom Santos and Steve Wilson) * is more elegant. I just hacked 'em in here so they are * immediately at hand. */ public void fireTreeNodesChanged( TreeModelEvent e ) { Enumeration listeners = listenerList.elements(); while ( listeners.hasMoreElements() ) { TreeModelListener listener = (TreeModelListener) listeners.nextElement(); listener.treeNodesChanged( e ); } } public void fireTreeNodesInserted( TreeModelEvent e ) { Enumeration listeners = listenerList.elements(); while ( listeners.hasMoreElements() ) { TreeModelListener listener = (TreeModelListener) listeners.nextElement(); listener.treeNodesInserted( e ); } } public void fireTreeNodesRemoved( TreeModelEvent e ) { Enumeration listeners = listenerList.elements(); while ( listeners.hasMoreElements() ) { TreeModelListener listener = (TreeModelListener) listeners.nextElement(); listener.treeNodesRemoved( e ); } } public void fireTreeStructureChanged( TreeModelEvent e ) { Enumeration listeners = listenerList.elements(); while ( listeners.hasMoreElements() ) { TreeModelListener listener = (TreeModelListener) listeners.nextElement(); listener.treeStructureChanged( e ); } } } }