Java tutorial
package org.activityinfo.ui.client.page.report; /* * #%L * ActivityInfo Server * %% * Copyright (C) 2009 - 2013 UNICEF * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program. If not, see * <http://www.gnu.org/licenses/gpl-3.0.html>. * #L% */ import com.extjs.gxt.ui.client.Style.HorizontalAlignment; import com.extjs.gxt.ui.client.core.El; import com.extjs.gxt.ui.client.event.ButtonEvent; import com.extjs.gxt.ui.client.event.Listener; import com.extjs.gxt.ui.client.event.MessageBoxEvent; import com.extjs.gxt.ui.client.event.SelectionListener; import com.extjs.gxt.ui.client.util.Margins; import com.extjs.gxt.ui.client.widget.Dialog; import com.extjs.gxt.ui.client.widget.MessageBox; import com.extjs.gxt.ui.client.widget.ProgressBar; import com.extjs.gxt.ui.client.widget.Text; import com.extjs.gxt.ui.client.widget.button.Button; import com.extjs.gxt.ui.client.widget.layout.VBoxLayout; import com.extjs.gxt.ui.client.widget.layout.VBoxLayout.VBoxLayoutAlign; import com.extjs.gxt.ui.client.widget.layout.VBoxLayoutData; import com.google.gwt.core.client.Scheduler; import com.google.gwt.http.client.*; import com.google.gwt.user.client.rpc.AsyncCallback; import com.google.gwt.user.client.ui.RootPanel; import org.activityinfo.i18n.shared.I18N; import org.activityinfo.legacy.client.Dispatcher; import org.activityinfo.legacy.shared.command.Filter; import org.activityinfo.legacy.shared.command.FilterUrlSerializer; import org.activityinfo.legacy.shared.command.RenderElement; import org.activityinfo.legacy.shared.command.RenderElement.Format; import org.activityinfo.legacy.shared.command.result.UrlResult; import org.activityinfo.legacy.shared.reports.model.ReportElement; import org.activityinfo.promise.Promise; public class ExportDialog extends Dialog { private final Dispatcher dispatcher; private ProgressBar bar; private Text downloadLink; private boolean canceled = false; private Button button; public ExportDialog(Dispatcher dispatcher) { this.dispatcher = dispatcher; setWidth(350); setHeight(175); setHeadingText(I18N.CONSTANTS.export()); setClosable(false); setButtonAlign(HorizontalAlignment.CENTER); VBoxLayout layout = new VBoxLayout(); layout.setVBoxLayoutAlign(VBoxLayoutAlign.LEFT); setLayout(layout); bar = new ProgressBar(); bar.setWidth(300); add(bar, new VBoxLayoutData(new Margins(20, 15, 25, 15))); downloadLink = new Text(I18N.CONSTANTS.clickToDownload()); downloadLink.setTagName("a"); downloadLink.setVisible(false); add(downloadLink, new VBoxLayoutData(0, 15, 0, 15)); } @Override protected void createButtons() { button = new Button(); button.setText(I18N.CONSTANTS.cancel()); button.addSelectionListener(new SelectionListener<ButtonEvent>() { @Override public void componentSelected(ButtonEvent ce) { ExportDialog.this.canceled = true; bar.reset(); hide(); } }); getButtonBar().add(button); } public void export(String filename, ReportElement model, Format format) { showStartProgress(); RenderElement command = new RenderElement(model, format); command.setFilename(filename); dispatcher.execute(command, new AsyncCallback<UrlResult>() { @Override public void onFailure(Throwable caught) { showError(); } @Override public void onSuccess(UrlResult result) { if (!canceled) { initiateDownload(result.getUrl()); } } }); } private void showStartProgress() { show(); bar.updateText(I18N.CONSTANTS.exportProgress()); bar.auto(); } private void showError() { MessageBox.alert(I18N.CONSTANTS.export(), I18N.CONSTANTS.serverError(), new Listener<MessageBoxEvent>() { @Override public void handleEvent(MessageBoxEvent be) { ExportDialog.this.hide(); } }); } private void initiateDownload(String url) { bar.reset(); bar.updateProgress(1.0, I18N.CONSTANTS.downloadReady()); button.setText(I18N.CONSTANTS.close()); tryStartDownloadWithIframe(url); downloadLink.getElement().setAttribute("href", url); downloadLink.setVisible(true); layout(true); } public void exportSites(Filter filter) { showStartProgress(); RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.POST, "/ActivityInfo/export"); requestBuilder.setHeader("Content-type", "application/x-www-form-urlencoded"); requestBuilder.setRequestData("filter=" + FilterUrlSerializer.toUrlFragment(filter)); requestBuilder.setCallback(new RequestCallback() { @Override public void onResponseReceived(Request request, Response response) { final String exportId = response.getText(); getDownloadUrl(exportId).then(new AsyncCallback<String>() { @Override public void onFailure(Throwable caught) { showError(); } @Override public void onSuccess(String downloadUrl) { initiateDownload(downloadUrl); } }); } @Override public void onError(Request request, Throwable exception) { showError(); } }); try { requestBuilder.send(); } catch (RequestException e) { showError(); } } private Promise<String> getDownloadUrl(String exportId) { final Promise<String> url = new Promise<>(); schedulePoll(exportId, url); return url; } private void schedulePoll(final String exportId, final Promise<String> downloadUrl) { Scheduler.get().scheduleFixedDelay(new Scheduler.RepeatingCommand() { @Override public boolean execute() { pollServer(exportId, downloadUrl); return false; } }, 1000); } private void pollServer(final String exportId, final Promise<String> downloadUrl) { RequestBuilder request = new RequestBuilder(RequestBuilder.GET, "/ActivityInfo/export?id=" + exportId); request.setCallback(new RequestCallback() { @Override public void onResponseReceived(Request request, Response response) { if (response.getStatusCode() == 200) { downloadUrl.onSuccess(response.getText()); } else { schedulePoll(exportId, downloadUrl); } } @Override public void onError(Request request, Throwable exception) { downloadUrl.onFailure(exception); } }); try { request.send(); } catch (RequestException e) { downloadUrl.onFailure(e); } } private void tryStartDownloadWithIframe(String url) { com.google.gwt.user.client.ui.Frame frame = new com.google.gwt.user.client.ui.Frame(url); El el = El.fly(frame.getElement()); el.setStyleAttribute("width", 0); el.setStyleAttribute("height", 0); el.setStyleAttribute("position", "absolute"); el.setStyleAttribute("border", 0); RootPanel.get().add(frame); } }