| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more contributor license |
| * agreements. See the NOTICE file distributed with this work for additional information regarding |
| * copyright ownership. The ASF licenses this file to You 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.apache.geode.alerting.internal; |
| |
| import org.apache.geode.alerting.internal.api.AlertingService; |
| import org.apache.geode.annotations.VisibleForTesting; |
| |
| /** |
| * The {@code DistributedSystem} connection uses {@code AlertingSession} to control the lifecycle |
| * of the registered {@code AlertingProvider}. |
| * |
| * <p> |
| * During initialization of {@code DistributedSystem} a new {@code AlertingSession} is instantiated |
| * and {@code createSession} will be invoked with a new instance of {@code ClusterAlertMessaging}. |
| * After |
| * a {@code DistributionConfig} exists, it will then invoke {@code startSession}. During disconnect, |
| * it will invoke {@code stopSession}. |
| * |
| * <p> |
| * The {@code AlertAppender} will capture the {@code ClusterAlertMessaging} in order to send out |
| * {@code Alert} messages to registered {@code Alert} listeners. {@code startSession} will cause |
| * the appender to unpause and begin processing all incoming log events. Any log event that meets |
| * the {@code AlertLevel} of one or more {@code Alert} listeners will result in the generation of |
| * an {@code Alert} being sent to those listeners. |
| */ |
| public class AlertingSession { |
| |
| private final AlertingSessionNotifier alertingSessionNotifier; |
| private State state = State.STOPPED; |
| |
| public static AlertingSession create() { |
| return create(AlertingSessionRegistryProvider.get()); |
| } |
| |
| @VisibleForTesting |
| static AlertingSession create(AlertingSessionNotifier alertingSessionListeners) { |
| return new AlertingSession(alertingSessionListeners); |
| } |
| |
| private AlertingSession(AlertingSessionNotifier alertingSessionNotifier) { |
| this.alertingSessionNotifier = alertingSessionNotifier; |
| } |
| |
| public synchronized void createSession(AlertingService alertingService) { |
| state = state.changeTo(State.CREATED); |
| alertingSessionNotifier.createSession(alertingService); |
| } |
| |
| public synchronized void startSession() { |
| state = state.changeTo(State.STARTED); |
| alertingSessionNotifier.startSession(); |
| } |
| |
| public synchronized void stopSession() { |
| state = state.changeTo(State.STOPPED); |
| alertingSessionNotifier.stopSession(); |
| } |
| |
| public synchronized void shutdown() { |
| // nothing |
| } |
| |
| @VisibleForTesting |
| AlertingSessionNotifier getAlertingSessionNotifier() { |
| return alertingSessionNotifier; |
| } |
| |
| synchronized State getState() { |
| return state; |
| } |
| |
| enum State { |
| CREATED, |
| STARTED, |
| STOPPED; |
| |
| State changeTo(final State newState) { |
| switch (newState) { |
| case CREATED: |
| if (this != STOPPED) { |
| throw new IllegalStateException("Session must not exist before creating"); |
| } |
| return CREATED; |
| case STARTED: |
| if (this != CREATED) { |
| throw new IllegalStateException("Session must be created before starting"); |
| } |
| return STARTED; |
| case STOPPED: |
| if (this != STARTED) { |
| throw new IllegalStateException("Session must be started before stopping"); |
| } |
| } |
| return STOPPED; |
| } |
| } |
| } |