com.google.gwt.dev.util.log.dashboard.DashboardNotifierFactory Maven / Gradle / Ivy
/*
* Copyright 2011 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.dev.util.log.dashboard;
/**
* Gets an instance of {@link DashboardNotifier} for sending data to a GWT
* dashboard.
*/
public class DashboardNotifierFactory {
private static final NoOpDashboardNotifier defaultNotifier = new NoOpDashboardNotifier();
private static DashboardNotifier theNotifier;
static {
setNotifier(createNotifier(System.getProperty("gwt.dashboard.notifierClass")));
}
/**
* Determines whether notifications to a GWT Dashboard are enabled. Returns
* true if the current notifier is not the default "no-op"
* instance.
*/
public static boolean areNotificationsEnabled() {
return theNotifier != defaultNotifier;
}
/**
* Returns an instance of {@code DashboardNotifier} for sending data to a GWT
* dashboard.
*/
public static DashboardNotifier getNotifier() {
return theNotifier;
}
/**
* Creates a {@code DashboardNotifier} from a given class name. The object is
* instantiated via reflection.
*
* @return the new notifier instance if the creation was successful or null on
* failure
*/
static DashboardNotifier createNotifier(String className) {
// Create the instance!
DashboardNotifier notifier = null;
if (className != null) {
try {
Class clazz = Class.forName(className);
notifier = (DashboardNotifier) clazz.newInstance();
} catch (Exception e) {
// print error and skip dashboard notifications...
new Exception("Unexpected failure while trying to load dashboard class: " + className
+ ". Notifications to the dashboard will be disabled.", e).printStackTrace();
return null;
}
}
return notifier;
}
/**
* Defines the {@code DashboardNotifier} returned by this factory. Exposed for
* unit testing purposes (to support mock notifier objects). If set to null, a
* default notifier (whose methods do nothing) will be returned by subsequent
* calls to {@code getNotifier}, not null.
*/
static void setNotifier(DashboardNotifier notifier) {
theNotifier = notifier == null ? defaultNotifier : notifier;
}
/**
* Prevents this class from being instantiated. Instead use static method
* {@link #getNotifier()}.
*/
private DashboardNotifierFactory() {
}
}