Java tutorial
/* * Copyright 2002-2019 the original author or authors. * * 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 * * https://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.springframework.integration.store; import java.util.Arrays; import java.util.Collection; import java.util.LinkedHashSet; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.jmx.export.annotation.ManagedAttribute; import org.springframework.jmx.export.annotation.ManagedOperation; import org.springframework.jmx.export.annotation.ManagedResource; import org.springframework.messaging.Message; /** * @author Dave Syer * @author Oleg Zhurakousky * @author Gary Russell * @author Artem Bilan * * @since 2.0 */ @ManagedResource public abstract class AbstractMessageGroupStore extends AbstractBatchingMessageGroupStore implements MessageGroupStore, Iterable<MessageGroup> { protected final Log logger = LogFactory.getLog(getClass()); // NOSONAR final private final Collection<MessageGroupCallback> expiryCallbacks = new LinkedHashSet<>(); private final MessageGroupFactory persistentMessageGroupFactory = new SimpleMessageGroupFactory( SimpleMessageGroupFactory.GroupType.PERSISTENT); private volatile boolean timeoutOnIdle; private boolean lazyLoadMessageGroups = true; protected AbstractMessageGroupStore() { super(); } protected AbstractMessageGroupStore(boolean lazyLoadMessageGroups) { this.lazyLoadMessageGroups = lazyLoadMessageGroups; } @Override protected MessageGroupFactory getMessageGroupFactory() { if (this.lazyLoadMessageGroups) { return this.persistentMessageGroupFactory; } else { return super.getMessageGroupFactory(); } } /** * Convenient injection point for expiry callbacks in the message store. Each of the callbacks provided will simply * be registered with the store using {@link #registerMessageGroupExpiryCallback(MessageGroupCallback)}. * @param expiryCallbacks the expiry callbacks to add */ public void setExpiryCallbacks(Collection<MessageGroupCallback> expiryCallbacks) { expiryCallbacks.forEach(this::registerMessageGroupExpiryCallback); } public boolean isTimeoutOnIdle() { return this.timeoutOnIdle; } /** * Allows you to override the rule for the timeout calculation. Typical timeout is based from the time * the {@link MessageGroup} was created. If you want the timeout to be based on the time * the {@link MessageGroup} was idling (e.g., inactive from the last update) invoke this method with 'true'. * Default is 'false'. * @param timeoutOnIdle The boolean. */ public void setTimeoutOnIdle(boolean timeoutOnIdle) { this.timeoutOnIdle = timeoutOnIdle; } /** * Specify if the result of the {@link #getMessageGroup(Object)} should be wrapped * to the {@link PersistentMessageGroup} - a lazy-load proxy for messages in group * Defaults to {@code true}. * <p> The target logic is based on the {@link SimpleMessageGroupFactory.GroupType#PERSISTENT}. * @param lazyLoadMessageGroups the {@code boolean} flag to use. * @since 4.3 */ public void setLazyLoadMessageGroups(boolean lazyLoadMessageGroups) { this.lazyLoadMessageGroups = lazyLoadMessageGroups; } @Override public void registerMessageGroupExpiryCallback(MessageGroupCallback callback) { if (callback instanceof UniqueExpiryCallback) { boolean uniqueExpiryCallbackPresent = this.expiryCallbacks.stream() .anyMatch(UniqueExpiryCallback.class::isInstance); if (uniqueExpiryCallbackPresent && this.logger.isErrorEnabled()) { this.logger.error("Only one instance of 'UniqueExpiryCallback' can be registered in the " + "'MessageGroupStore'. Use a separate 'MessageGroupStore' for each aggregator/resequencer."); } } this.expiryCallbacks.add(callback); } @Override @ManagedOperation public synchronized int expireMessageGroups(long timeout) { int count = 0; long threshold = System.currentTimeMillis() - timeout; for (MessageGroup group : this) { long timestamp = group.getTimestamp(); if (this.isTimeoutOnIdle() && group.getLastModified() > 0) { timestamp = group.getLastModified(); } if (timestamp <= threshold) { count++; expire(copy(group)); } } return count; } /** * Used by expireMessageGroups. We need to return a snapshot of the group * at the time the reaper runs, so we can properly detect if the * group changed between now and the attempt to expire the group. * Not necessary for persistent stores, so the default behavior is * to just return the group. * @param group The group. * @return The group, or a copy. * @since 4.0.1 */ protected MessageGroup copy(MessageGroup group) { return group; } @Override @ManagedAttribute public int getMessageCountForAllMessageGroups() { int count = 0; for (MessageGroup group : this) { count += group.size(); } return count; } @Override @ManagedAttribute public int getMessageGroupCount() { int count = 0; for (@SuppressWarnings("unused") MessageGroup group : this) { count++; } return count; } @Override public MessageGroupMetadata getGroupMetadata(Object groupId) { throw new UnsupportedOperationException("Not yet implemented for this store"); } @Override public void removeMessagesFromGroup(Object key, Message<?>... messages) { removeMessagesFromGroup(key, Arrays.asList(messages)); } @Override public MessageGroup addMessageToGroup(Object groupId, Message<?> message) { addMessagesToGroup(groupId, message); return getMessageGroup(groupId); } private void expire(MessageGroup group) { RuntimeException exception = null; for (MessageGroupCallback callback : this.expiryCallbacks) { try { callback.execute(this, group); } catch (RuntimeException e) { if (exception == null) { exception = e; } this.logger.error("Exception in expiry callback", e); } } if (exception != null) { throw exception; } } }