Java tutorial
/** * DataCleaner (community edition) * Copyright (C) 2013 Human Inference * * This copyrighted material is made available to anyone wishing to use, modify, * copy, or redistribute it subject to the terms and conditions of the GNU * Lesser General Public License, as published by the Free Software Foundation. * * 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 Lesser General Public License * for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this distribution; if not, write to: * Free Software Foundation, Inc. * 51 Franklin Street, Fifth Floor * Boston, MA 02110-1301 USA */ package org.eobjects.datacleaner.monitor.util; import java.util.Set; import org.eobjects.datacleaner.monitor.shared.JavaScriptCallbacks; import org.eobjects.datacleaner.monitor.shared.model.DCUserInputException; import org.eobjects.datacleaner.monitor.shared.widgets.ButtonPanel; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.GWT.UncaughtExceptionHandler; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.http.client.Response; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.DialogBox; import com.google.gwt.user.client.ui.DialogBox.Caption; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.TextArea; import com.google.web.bindery.event.shared.UmbrellaException; /** * Utility class for handling errors in GWT code */ public class ErrorHandler { /** * This dialog box instance will be shared for all messages */ private static DialogBox sharedDialogBox; private static DialogBox getDialogBox() { if (sharedDialogBox == null) { Caption caption = new DialogBox.CaptionImpl(); caption.setText("Error"); sharedDialogBox = new DialogBox(false, true, caption); sharedDialogBox.addStyleName("ErrorDialog"); } return sharedDialogBox; } /** * This method first call handleError method which is a native method to * call onError JS function, in case onError JS method is not present on * page it simply shows an error dialog as an alert. * * @param headerMessage * @param additionalDetails * @param t */ public static void showErrorDialog(final String headerMessage, final String additionalDetails, final Throwable t) { String oneLineMessage = buildOneLineMessage(headerMessage, additionalDetails, t); if (t instanceof DCUserInputException) { GWT.log("User input exception", t); if (JavaScriptCallbacks.onError(oneLineMessage, true)) { return; } Window.alert(oneLineMessage); return; } GWT.log("Uncaught exception", t); GWT.log("Additional details: " + additionalDetails); final String detailsMessage; if (t instanceof UmbrellaException) { // sometimes several exceptions are bundled in an UmbrellaException Set<Throwable> causes = ((UmbrellaException) t).getCauses(); if (causes.size() == 1) { Throwable cause = causes.iterator().next(); showErrorDialog(cause.getMessage(), additionalDetails, cause); return; } StringBuilder messageBuilder = new StringBuilder(); for (Throwable cause : causes) { if (messageBuilder.length() != 0) { messageBuilder.append("\n"); } messageBuilder.append(cause); messageBuilder.append(": "); messageBuilder.append(cause.getMessage()); } detailsMessage = messageBuilder.toString(); } else { detailsMessage = t.getMessage(); } if (JavaScriptCallbacks.onError(oneLineMessage, false)) { return; } final String details = detailsMessage + "\n\n" + t; showErrorDialog(headerMessage, details, additionalDetails); } private static String buildOneLineMessage(String headerMessage, String additionalDetails, Throwable t) { final StringBuilder oneLineMessage = new StringBuilder(); if (headerMessage != null && !"".equals(headerMessage)) { oneLineMessage.append(headerMessage); } if (additionalDetails != null && !"".equals(additionalDetails)) { if (oneLineMessage.length() != 0) { oneLineMessage.append(": "); } oneLineMessage.append(additionalDetails); } String exceptionMessage = t.getMessage(); if (exceptionMessage != null && !"".equals(exceptionMessage) && oneLineMessage.indexOf(exceptionMessage) == -1) { if (oneLineMessage.length() != 0) { oneLineMessage.append(": "); } oneLineMessage.append(exceptionMessage); } return oneLineMessage.toString(); } /** * Shows an error dialog * * @param message * @param res */ public static void showErrorDialog(String message, Response res) { final String mainMessage = message + ":\n" + res.getStatusCode() + ":" + res.getStatusText(); final String details = res.getText(); showErrorDialog(mainMessage, details, (String) null); } /** * Shows an error dialog * * @param message */ public static void showErrorDialog(String message) { showErrorDialog(message, (String) null, (String) null); } /** * Shows an error dialog * * @param messageHeader * @param details * @param additionalDetails */ public static void showErrorDialog(String messageHeader, String details, String additionalDetails) { final DialogBox dialogBox = getDialogBox(); final FlowPanel panel = new FlowPanel(); final Label messageLabel = new Label(messageHeader); messageLabel.addStyleName("Message"); panel.add(messageLabel); if (details != null && details.trim().length() > 0) { final TextArea textArea = new TextArea(); textArea.setText(details); textArea.setReadOnly(true); textArea.addStyleName("Details"); panel.add(textArea); } if (additionalDetails != null && additionalDetails.trim().length() > 0) { final TextArea textArea = new TextArea(); textArea.setText(additionalDetails); textArea.setReadOnly(true); textArea.addStyleName("AdditionalMessageDetails"); panel.add(textArea); } final Button closeButton = new Button("Close"); closeButton.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { dialogBox.hide(); } }); final ButtonPanel buttonPanel = new ButtonPanel(); buttonPanel.add(closeButton); panel.add(buttonPanel); dialogBox.setWidget(panel); dialogBox.center(); dialogBox.show(); } /** * Creates an {@link UncaughtExceptionHandler} for use by * {@link GWT#setUncaughtExceptionHandler(UncaughtExceptionHandler)} * * @return */ public static UncaughtExceptionHandler getUncaughtExceptionHandler() { return new UncaughtExceptionHandler() { @Override public void onUncaughtException(Throwable e) { showErrorDialog("Unexpected error occurred", (String) null, e); } }; } }