Java/GWT/XML

GWT and XML

/*
 * Copyright 2006 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.sample.simplexml.client;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.HTTPRequest;
import com.google.gwt.user.client.ResponseTextHandler;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HTMLTable;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TabPanel;
import com.google.gwt.xml.client.Document;
import com.google.gwt.xml.client.Element;
import com.google.gwt.xml.client.Node;
import com.google.gwt.xml.client.NodeList;
import com.google.gwt.xml.client.XMLParser;
/**
 * A very simple XML Example where we take a customer profile and display it on
 * a page.
 */
public class SimpleXML implements EntryPoint {
  private static final String XML_LABEL_STYLE = "xmlLabel";
  private static final String USER_TABLE_LABEL_STYLE = "userTableLabel";
  private static final String USER_TABLE_STYLE = "userTable";
  private static final String NOTES_STYLE = "notes";
  public void onModuleLoad() {
    HTTPRequest.asyncGet("customerRecord.xml", new ResponseTextHandler() {
      public void onCompletion(String responseText) {
        // In the real world, this text would come as a RPC response. This
        // technique is great for testing and samples though!
        renderXML(responseText);
      }
      private FlexTable createOrderTable(FlowPanel xmlParsed, String label) {
        HTML orderTableLabel = new HTML("<h2>" + label + "</h2>");
        xmlParsed.add(orderTableLabel);
        FlexTable orderTable = new FlexTable();
        orderTable.setStyleName(USER_TABLE_STYLE);
        orderTable.setBorderWidth(3);
        orderTable.getRowFormatter().setStyleName(0, USER_TABLE_LABEL_STYLE);
        orderTable.setText(0, 0, "Order ID");
        orderTable.setText(0, 1, "Item");
        orderTable.setText(0, 2, "Ordered On");
        orderTable.setText(0, 3, "Street");
        orderTable.setText(0, 4, "City");
        orderTable.setText(0, 5, "State");
        orderTable.setText(0, 6, "Zip");
        xmlParsed.add(orderTable);
        return orderTable;
      }
      /**
       * Creates the xml representation of xmlText. xmlText is assumed to have
       * been validated for structure on the server.
       * 
       * @param xmlText xml text
       * @param xmlParsed panel to display customer record
       */
      private void customerPane(String xmlText, FlowPanel xmlParsed) {
        Document customerDom = XMLParser.parse(xmlText);
        Element customerElement = customerDom.getDocumentElement();
        // Must do this if you ever use a raw node list that you expect to be
        // all elements.
        XMLParser.removeWhitespace(customerElement);
        // Customer Name
        String nameValue = getElementTextValue(customerElement, "name");
        String title = "<h1>" + nameValue + "</h1>";
        HTML titleHTML = new HTML(title);
        xmlParsed.add(titleHTML);
        // Customer Notes
        String notesValue = getElementTextValue(customerElement, "notes");
        Label notesText = new Label();
        notesText.setStyleName(NOTES_STYLE);
        notesText.setText(notesValue);
        xmlParsed.add(notesText);
        // Pending orders UI setup
        FlexTable pendingTable = createOrderTable(xmlParsed, "Pending Orders");
        FlexTable completedTable = createOrderTable(xmlParsed, "Completed");
        completedTable.setText(0, 7, "Shipped by");
        // Fill Orders Table
        NodeList orders = customerElement.getElementsByTagName("order");
        int pendingRowPos = 0;
        int completedRowPos = 0;
        for (int i = 0; i < orders.getLength(); i++) {
          Element order = (Element) orders.item(i);
          HTMLTable table;
          int rowPos;
          if (order.getAttribute("status").equals("pending")) {
            table = pendingTable;
            rowPos = ++pendingRowPos;
          } else {
            table = completedTable;
            rowPos = ++completedRowPos;
          }
          int columnPos = 0;
          fillInOrderTableRow(customerElement, order, table, rowPos, columnPos);
        }
      }
      private void fillInOrderTableRow(Element customerElement, Element order,
          HTMLTable table, int rowPos, int columnPos) {
        // Order ID
        String orderId = order.getAttribute("id");
        table.setText(rowPos, columnPos++, orderId);
        // Item
        Element item = (Element) order.getElementsByTagName("item").item(0);
        String itemUPC = item.getAttribute("upc");
        String itemName = item.getFirstChild().getNodeValue();
        Label itemLabel = new Label(itemUPC);
        itemLabel.setTitle(itemName);
        table.setWidget(rowPos, columnPos++, itemLabel);
        // Ordered On
        String orderedOnValue = getElementTextValue(customerElement,
          "orderedOn");
        table.setText(rowPos, columnPos++, orderedOnValue);
        // Address
        Element address = (Element) order.getElementsByTagName("address").item(
          0);
        XMLParser.removeWhitespace(address);
        NodeList lst = address.getChildNodes();
        for (int j = 0; j < lst.getLength(); j++) {
          Element next = (Element) lst.item(j);
          String addressPartText = next.getFirstChild().getNodeValue();
          table.setText(rowPos, columnPos++, addressPartText);
        }
        // Shipped By (optional attribute)
        NodeList shippedByList = order.getElementsByTagName("shippingInfo");
        if (shippedByList.getLength() == 1) {
          Element shippedBy = (Element) shippedByList.item(0);
          // Depending upon the shipper, different attributes might be
          // available, so XML carries the display info
          FlexTable shippedByTable = new FlexTable();
          shippedByTable.getRowFormatter().setStyleName(0,
            USER_TABLE_LABEL_STYLE);
          shippedByTable.setBorderWidth(1);
          NodeList shippedByParts = shippedBy.getChildNodes();
          for (int j = 0; j < shippedByParts.getLength(); j++) {
            Node next = shippedByParts.item(j);
            Element elem = (Element) next;
            shippedByTable.setText(0, j, elem.getAttribute("title"));
            shippedByTable.setText(1, j, elem.getFirstChild().getNodeValue());
          }
          table.setWidget(rowPos, columnPos++, shippedByTable);
        }
      }
      /**
       * Utility method to return the values of elements of the form <myTag>tag
       * value</myTag>
       */
      private String getElementTextValue(Element parent, String elementTag) {
        // If the xml is not coming from a known good source, this method would
        // have to include safety checks.
        return parent.getElementsByTagName(elementTag).item(0).getFirstChild()
          .getNodeValue();
      }
      private void renderXML(String xmlText) {
     
        final TabPanel tab = new TabPanel();
        final FlowPanel xmlSource = new FlowPanel();
        final FlowPanel xmlParsed = new FlowPanel();
        tab.add(xmlParsed, "Customer Pane");
        tab.add(xmlSource, "XML Source");
        tab.selectTab(0);
        RootPanel.get().add(tab);
        xmlPane(xmlText, xmlSource);
        customerPane(xmlText, xmlParsed);
      }
      /**
       * Show the raw XML.
       * 
       * @param xmlText
       * @param xmlSource
       */
      private void xmlPane(String xmlText, final FlowPanel xmlSource) {
        xmlText = xmlText.replaceAll("<", "&#60;");
        xmlText = xmlText.replaceAll(">", "&#62;");
        Label xml = new HTML("<pre>" + xmlText + "</pre>", false);
        xml.setStyleName(XML_LABEL_STYLE);
        xmlSource.add(xml);
      }
    });
  }
}