Java tutorial
/******************************************************************************* * * Copyright 2011 Spiffy UI Team * * 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 org.spiffyui.client; import java.util.Date; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.safehtml.shared.SafeHtmlUtils; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Element; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.Event.NativePreviewEvent; import com.google.gwt.user.client.ui.Anchor; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.RootPanel; /** * <p> * This class is a set of static utility methods for showing messages and errors * in the browser and handle them all in a consistent way. * </p> * * <p> * Applications have a large variety of messages they show to users. They can vary * from "That name is already taken" to "Your database server crashed." These * messages have a very different level of severity. To support that the Spiffy * UI framework supports four levels of user messages. * </p> * * <p> * <b>Informational messages</b> tell the user something they need to know but don't * need to respond to. "Your changes are saved" is a common example of this type * of message. * </p> * * <p> * <b>Warning messages</b> tell the user something they need to respond to like * "That username is already taken." * </p> * * <p> * <b>Error messages</b> tell the user something went wrong. For example, * "Unable to contact your email server." * </p> * * <p> * <b>Fatal error messages</b> tell the user something went so wrong the system * probably can't continue. "Unable to contact your server" is a typical fatal * error message. * </p> * * <p> * The first three types of messages are transient. The UI follows the Humanized * Messages idiom layed out by <a href="http://en.wikipedia.org/wiki/Jef_Raskin"> * Jef Raskin</a>. They show up on top of the content and fade in a small amount * of time. Wiggling your mouse on them will make them fade faster. * </p> * * <p> * Error messages and some warnings will also show up in the error log at the bottom * of the page. This makes it easy to find them again if the user needs to. * </p> * * <p> * Fatal errors are different since they normally prevent the program from continuing. * These errors show up on top of the screen and do not move until the user clicks on * them. * </p> * * <p> * Each of these messages can be seen on the Widgets page of the Spiffy UI Application. * </p> * * <p> * Many of the methods use the Humanized Message Panels and require the Spiffy UI * JavaScript libraries. This class also depends on the Spiffy UI HTML structure. * </p> */ public final class MessageUtil { private static boolean g_shouldShow = true; /** * Making sure this class can't be instantiated. */ private MessageUtil() { } static { createJSFunctions(); } /** * This is the singleton instance of the error panel. */ public static final ErrorPanel ERROR_PANEL = new ErrorPanel(); /** * This is the singleton instance of the page warning panel. */ public static final PageWarningPanel PAGE_WARNING_PANEL = new PageWarningPanel(); static { setLogTitleJS("Error Log"); } /** * Show a fatal error message in the error panel with the ID errorPanel. * * This message has a default style of * * @param msg the message to show in HTML */ public static void showFatalError(String msg) { if (g_shouldShow) { ERROR_PANEL.setErrorMessage(msg); } logError(msg); } /** * This method shows a page level warning for the page. These warnings * are meant to indicate that the page is fundamentally broken or unavailable. * The message shows up large in the middle of the page and hide all of * the contents of the page except for the header and footer. * * @param msg the message to show in HTML */ public static void showPageLevelWarning(String msg) { PAGE_WARNING_PANEL.setErrorMessage(msg); } /** * <p> * Show a warning message. * </p> * * <p> * This message has a default style of white text with a red background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgErr</li> * </ul> * * @param msg the message to show in HTML */ public static void showWarning(String msg) { showWarning(msg, true); } private static void showWarning(String msg, Boolean shouldLog) { showWarning(msg, shouldLog.booleanValue()); } /** * <p> * Show a warning message. * </p> * * <p> * This message has a default style of black text with a yellow background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgWarn</li> * </ul> * * @param msg the message to show in HTML * @param shouldLog indicates if this warning should be sent to the in-browser error log */ public static void showWarning(String msg, boolean shouldLog) { showWarningJS(msg); if (shouldLog) { logWarning(msg); } } /** * <p> * Show a warning message. * </p> * * <p> * This message has a default style of black text with a yellow background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgWarn</li> * </ul> * * @param msg the message to show in HTML * @param shouldLog indicates if this warning should be sent to the in-browser error log * @param isSafe if this field is true then this just calls showMessage, otherwise it * runs the specified message through the GWT SaveHtmlUtils */ public static void showWarning(String msg, boolean shouldLog, boolean isSafe) { if (isSafe) { showWarning(msg, shouldLog); } else { showWarning(SafeHtmlUtils.fromString(msg).asString(), shouldLog); } } /** * Sets if the message helper should show messages at all. * * @param shouldShow true if it should and false otherwise */ public static void setShouldShowMessages(boolean shouldShow) { g_shouldShow = shouldShow; setShouldShowMessagesJS(shouldShow); } /** * Gets if the message util is showing messages. * * @return true if messages are shown and false otherwise */ public static boolean getShouldShowMessages() { return g_shouldShow; } private static native void setShouldShowMessagesJS(boolean shouldShow) /*-{ humanMsg.shouldShow = shouldShow; }-*/; private static native void showWarningJS(String msg) /*-{ $wnd.humanMsg.setup(); $wnd.jQuery("#humanMsg").removeClass('humanMsgErr').removeClass('humanMsgInfo').addClass('humanMsgWarn'); $wnd.humanMsg.displayMsg(msg, false); }-*/; /** * <p> * Show an information message. * </p> * * <p> * This message has a default style of white text with a black background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgInfo</li> * </ul> * * @param msg the message to show in HTML */ public static native void showMessage(String msg) /*-{ $wnd.humanMsg.setup(); $wnd.jQuery("#humanMsg").removeClass('humanMsgErr').removeClass('humanMsgWarn').addClass('humanMsgInfo'); $wnd.humanMsg.displayMsg(msg, false); }-*/; /** * <p> * Show an information message. * </p> * * <p> * This message has a default style of white text with a black background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgInfo</li> * </ul> * * @param msg the message to show in HTML * @param isSafe if this field is true then this just calls showMessage, otherwise it * runs the specified message through the GWT SaveHtmlUtils */ public static void showMessage(String msg, boolean isSafe) { if (isSafe) { showMessage(msg); } else { showMessage(SafeHtmlUtils.fromString(msg).asString()); } } /** * <p> * Show an warning message. * </p> * * <p> * This message has a default style of white text with a black background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgInfo</li> * </ul> * * @param msg the message to show in HTML * * @param className * the name of the class to apply */ public static native void showMessage(String msg, String className) /*-{ $wnd.humanMsg.setup(); $wnd.jQuery("#humanMsg").removeClass('humanMsgErr').removeClass('humanMsgWarn').removeClass('humanMsgInfo').addClass(className); $wnd.humanMsg.displayMsg(msg, false); }-*/; /** * Show a temporary error message and logs it to the client-side error log * * @param msg the message to show in HTML */ public static void showError(String msg) { showErrorJS(msg); logError(msg); } /** * <p> * Show aan error message. * </p> * * <p> * This message has a default style of black text with a red background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgErr</li> * </ul> * * @param errorMsg the error message for the alert in HTML * @param logMsg the message for the error log in HTML */ public static void showError(String errorMsg, String logMsg) { showErrorJS(errorMsg); logError(logMsg); } /** * <p> * Show aan error message. * </p> * * <p> * This message has a default style of black text with a red background. * </p> * * <h3>CSS Style Ryles</h3> * * <ul> * <li>.humanMsgErr</li> * </ul> * * @param errorMsg the error message for the alert in HTML * @param logMsg the message for the error log in HTML * @param isSafe if this field is true then this just calls showMessage, otherwise it * runs the specified message through the GWT SaveHtmlUtils */ public static void showError(String errorMsg, String logMsg, boolean isSafe) { if (isSafe) { showError(errorMsg, logMsg); } else { showError(SafeHtmlUtils.fromString(errorMsg).asString(), SafeHtmlUtils.fromString(logMsg).asString()); } } private static native void showErrorJS(String msg) /*-{ $wnd.humanMsg.setup(); $wnd.jQuery("#humanMsg").removeClass('humanMsgInfo').removeClass('humanMsgWarn').addClass('humanMsgErr'); $wnd.humanMsg.displayMsg(msg, false); }-*/; /** * Write a message to the error log * * @param msg the message to show in HTML */ public static void logError(String msg) { logErrorJS(escapeString(msg)); } /** * Write a message to the error log * * @param msg the message to show in HTML */ public static void logWarning(String msg) { logErrorJS(escapeString(msg)); } private static String escapeString(String s) { if (s == null) { return ""; } return "<span class=\"weak\">" + JSDateUtil.getShortTime(new Date()) + "</span> " + s.replaceAll("\\<", "<").replaceAll("\\>", ">"); } private static native void logErrorJS(String msg) /*-{ $wnd.humanMsg.log(msg); }-*/; /** * Set the title of the error log. It may not contain HTML * * @param title the error log title */ public static native void setLogTitleJS(String title) /*-{ $wnd.humanMsg.setLogTitle(title); }-*/; private static native void createJSFunctions() /*-{ $wnd.spiffyui.showPageLevelWarning = function(msg) { @org.spiffyui.client.MessageUtil::showPageLevelWarning(Ljava/lang/String;)(msg); } $wnd.spiffyui.showFatalError = function(msg) { @org.spiffyui.client.MessageUtil::showFatalError(Ljava/lang/String;)(msg); } $wnd.spiffyui.showError = function(msg) { @org.spiffyui.client.MessageUtil::showError(Ljava/lang/String;)(msg); } $wnd.spiffyui.showWarning = function(msg, shouldLog) { if (shouldLog === null) { shouldLog = true; } @org.spiffyui.client.MessageUtil::showWarning(Ljava/lang/String;Ljava/lang/Boolean;)(msg,shouldLog); } $wnd.spiffyui.showMessage = function(msg) { @org.spiffyui.client.MessageUtil::showMessage(Ljava/lang/String;)(msg); } }-*/; } /** * The error panel show fatal errors in the UI */ class ErrorPanel extends Composite implements Event.NativePreviewHandler { private Label m_label; private FlowPanel m_panel; public ErrorPanel() { RootPanel root = RootPanel.get("mainContent"); if (root == null) { throw new IllegalStateException( "Unable to locate the errorpanel element. You must import spiffyui.min.js before using the MessageUtil."); } m_panel = new FlowPanel(); m_panel.getElement().setId("errorpanel"); m_label = new Label("", true); m_panel.add(m_label); Anchor clear = new Anchor("X"); clear.getElement().setId("errorpanel_hide"); clear.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { event.preventDefault(); JSUtil.slideUp("#" + m_panel.getElement().getId(), "fast"); } }); m_panel.add(clear); m_panel.setVisible(false); root.insert(m_panel, 0); //Any click anywhere will close Event.addNativePreviewHandler(this); } /** * Sets a message in the error panel and makes it visible * * @param message * the message */ public void setErrorMessage(String message) { makeVisible(); m_label.setText(message); } /** * Appends a message to the error panel and makes it visible * * @param message * the message */ public void appendErrorMessage(String message) { makeVisible(); m_label.setText(m_label.getText() + message); } /** * Clears the error panel. This method will make the panel invisible. */ public void clear() { m_label.setText(""); m_panel.setVisible(false); } private void makeVisible() { if (!m_panel.isVisible()) { JSUtil.slideDown("#" + m_panel.getElement().getId(), "normal"); } } @Override public void onPreviewNativeEvent(NativePreviewEvent event) { if (event.getTypeInt() != Event.ONCLICK) { return; } Element target = (Element) com.google.gwt.dom.client.Element.as(event.getNativeEvent().getEventTarget()); if (null == target) { return; } //any click on this will dismiss the panel if (DOM.isOrHasChild(m_panel.getElement(), target)) { JSUtil.slideUp("#" + m_panel.getElement().getId(), "fast"); } } } /** * The page warning shows page level warnings in the UI */ class PageWarningPanel extends Composite { private Label m_label; private FlowPanel m_panel; public PageWarningPanel() { RootPanel root = RootPanel.get("main"); if (root == null) { throw new IllegalStateException( "Unable to locate the warning panel element. You must import spiffyui.min.js before using the MessageUtil."); } m_panel = new FlowPanel(); m_panel.getElement().setId("pagewarningpanel"); m_label = new Label("", true); m_panel.add(m_label); m_panel.setVisible(false); root.add(m_panel); } /** * Sets a message in the error panel and makes it visible * * @param message * the message */ public void setErrorMessage(String message) { makeVisible(); m_label.setText(message); } /** * Appends a message to the error panel and makes it visible * * @param message * the message */ public void appendErrorMessage(String message) { makeVisible(); m_label.setText(m_label.getText() + message); } /** * Clears the error panel. This method will make the panel invisible. */ public void clear() { m_label.setText(""); m_panel.setVisible(false); } private void makeVisible() { if (!m_panel.isVisible()) { JSUtil.slideDown("#" + m_panel.getElement().getId(), "normal"); JSUtil.hide("mainBody"); } } }