Java tutorial
// Copyright 2010 Google Inc. All Rights Reseved. // // 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.testing.testify.risk.frontend.client; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.core.client.GWT; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.event.logical.shared.ValueChangeHandler; import com.google.gwt.user.client.History; import com.google.gwt.user.client.rpc.AsyncCallback; import com.google.gwt.user.client.ui.LayoutPanel; import com.google.gwt.user.client.ui.Panel; import com.google.gwt.user.client.ui.RootLayoutPanel; import com.google.gwt.user.client.ui.Widget; import com.google.testing.testify.risk.frontend.model.Project; import com.google.testing.testify.risk.frontend.shared.rpc.DataRpc; import com.google.testing.testify.risk.frontend.shared.rpc.DataRpcAsync; import com.google.testing.testify.risk.frontend.shared.rpc.ProjectRpc; import com.google.testing.testify.risk.frontend.shared.rpc.ProjectRpcAsync; import com.google.testing.testify.risk.frontend.shared.rpc.UserRpc; import com.google.testing.testify.risk.frontend.shared.rpc.UserRpcAsync; /** * Entry point for Test Analytics application. * * @author jimr@google.com (Jim Reardon) */ public class TaEntryPoint implements EntryPoint { private Panel contentPanel; private ProjectRpcAsync projectService; private UserRpcAsync userService; private DataRpcAsync dataService; private static final String HOMEPAGE_HISTORY_TOKEN = "/homepage"; // URL related error messages. private static final String INVALID_URL = "Invalid URL"; private static final String INVALID_URL_TEXT = "The page could not be found."; private static final String INVALID_PROJECT_ID_TEXT = "No project with that ID was found."; // Project-load related error messages. private static final String ERROR_LOADING_PROJECT = "Error loading project"; private static final String ERROR_LOADING_PROJECT_TEXT = "There was an error loading the requested project"; private static final String PROJECT_NOT_FOUND = "Project not found"; private static final String PROJECT_ID_NOT_FOUND_TEXT = "No project with that ID was found."; /** UI for the currently opened project. */ private TaApplication currentApplicationInstance = null; /** * Entry point for the application. */ @Override public void onModuleLoad() { projectService = GWT.create(ProjectRpc.class); userService = GWT.create(UserRpc.class); dataService = GWT.create(DataRpc.class); contentPanel = new LayoutPanel(); RootLayoutPanel.get().add(contentPanel); // Handle history changes. (Such as clicking a navigation hyperlink.) History.addValueChangeHandler(new ValueChangeHandler<String>() { @Override public void onValueChange(ValueChangeEvent<String> event) { String historyToken = event.getValue(); handleUrl(historyToken); } }); handleUrl(History.getToken()); } /** * Handles the URL, updating any UI elements for the current Testify application if necessary. */ private void handleUrl(String url) { // Intercept well-known pages. if ((url.length() == 0) || ("/".equals(url)) || (HOMEPAGE_HISTORY_TOKEN.equals(url))) { displayHomePage(); return; } // Expected format: "/project-id/target-page" // or: "/project-id/target-page/page-data" (project data is passed into the project page). // Thus part 0 will be an empty string, part 1 will be the project ID, part 2 the page name, // and part 3 the page data. String[] parts = url.split("/"); if ((parts.length < 2) || (parts[0].length() != 0)) { displayErrorPage(INVALID_URL, INVALID_URL_TEXT); return; } // The first part, the project ID. Long projectId = tryParseLong(parts[1]); if (projectId == null) { displayErrorPage(INVALID_URL, INVALID_PROJECT_ID_TEXT); return; } // Page name. String pageName = (parts.length > 2 ? parts[2] : null); // Page has data that should be sent to the target page. String pageData = (parts.length > 3 ? parts[3] : null); // Attempt to switch the page view. if (currentApplicationInstance != null && (currentApplicationInstance.getProject().getProjectId().equals(projectId))) { currentApplicationInstance.switchToPage(pageName, pageData); } else { // Otherwise, attempt to load the project and switch the view. loadProjectAndSwitchToUrl(projectId, url); } } /** * Performs an asynchronous load of a project with the given ID name. Afterwards, navigates to the * target URL. */ private void loadProjectAndSwitchToUrl(final long projectId, final String targetUrl) { projectService.getProjectById(projectId, new AsyncCallback<Project>() { @Override public void onFailure(Throwable caught) { displayErrorPage(ERROR_LOADING_PROJECT, ERROR_LOADING_PROJECT_TEXT); } @Override public void onSuccess(Project result) { if (result == null) { displayErrorPage(PROJECT_NOT_FOUND, PROJECT_ID_NOT_FOUND_TEXT); } else { displayProjectView(result); handleUrl(targetUrl); } } }); } /** * Switches the application's view to displays an error message. */ private void displayErrorPage(String errorType, String errorMessage) { GWT.log("General error: " + errorType); GeneralErrorPage errorPage = new GeneralErrorPage(); errorPage.setErrorType(errorType); errorPage.setErrorText(errorMessage); setPageContent(errorPage); } /** * Switches the application's view to the home page. */ private void displayHomePage() { final HomePage homePage = new HomePage(projectService, userService); setPageContent(homePage); } /** * Switches the application's view to a specific Project. */ public void displayProjectView(Project project) { // All projects must be serialized (have a Project ID) first. if (project.getProjectId() == null) { return; } GWT.log("Switching to view project " + project.getProjectId().toString()); currentApplicationInstance = new TaApplication(project, projectService, userService, dataService); setPageContent(currentApplicationInstance); } /** * Sets the GWT page to display the provided content. */ private void setPageContent(Widget content) { contentPanel.clear(); contentPanel.add(content); } /** * Attempts to parse the given string as integer, if not returns null. */ private Long tryParseLong(String text) { Long result = null; try { return Long.parseLong(text); } catch (NumberFormatException nfe) { return null; } } }