Java tutorial
/* * Copyright 2007 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.http.client.Request; import com.google.gwt.http.client.RequestBuilder; import com.google.gwt.http.client.RequestCallback; import com.google.gwt.http.client.RequestException; import com.google.gwt.http.client.Response; import com.google.gwt.user.client.Window; 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() { RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, "customerRecord.xml"); try { requestBuilder.sendRequest(null, new RequestCallback() { public void onError(Request request, Throwable exception) { requestFailed(exception); } public void onResponseReceived(Request request, Response response) { renderXML(response.getText()); } }); } catch (RequestException ex) { requestFailed(ex); } } 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); } private void requestFailed(Throwable exception) { Window.alert("Failed to send the request. The error message was: " + exception.getMessage()); } /** * Show the raw XML. * * @param xmlText * @param xmlSource */ private void xmlPane(String xmlText, final FlowPanel xmlSource) { xmlText = xmlText.replaceAll("<", "<"); xmlText = xmlText.replaceAll(">", ">"); Label xml = new HTML("<pre>" + xmlText + "</pre>", false); xml.setStyleName(XML_LABEL_STYLE); xmlSource.add(xml); } }