Java tutorial
/* * 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.sling.commons.messaging.mail.internal; import java.io.IOException; import java.util.Collections; import java.util.Map; import java.util.concurrent.CompletableFuture; import java.util.concurrent.CompletionException; import javax.annotation.Nonnull; import javax.mail.MessagingException; import org.apache.commons.mail.Email; import org.apache.commons.mail.EmailException; import org.apache.sling.commons.messaging.MessageService; import org.apache.sling.commons.messaging.Result; import org.apache.sling.commons.messaging.mail.MailBuilder; import org.apache.sling.commons.messaging.mail.MailResult; import org.apache.sling.commons.messaging.mail.MailUtil; import org.apache.sling.commons.threads.ThreadPool; import org.apache.sling.commons.threads.ThreadPoolManager; import org.osgi.framework.Constants; import org.osgi.service.component.annotations.Activate; import org.osgi.service.component.annotations.Component; import org.osgi.service.component.annotations.Deactivate; import org.osgi.service.component.annotations.Modified; import org.osgi.service.component.annotations.Reference; import org.osgi.service.component.annotations.ReferenceCardinality; import org.osgi.service.component.annotations.ReferencePolicy; import org.osgi.service.component.annotations.ReferencePolicyOption; import org.osgi.service.metatype.annotations.Designate; import org.slf4j.Logger; import org.slf4j.LoggerFactory; @Component(service = MessageService.class, property = { Constants.SERVICE_DESCRIPTION + "=Service to send messages by mail.", Constants.SERVICE_VENDOR + "=The Apache Software Foundation" }) @Designate(ocd = SimpleMailServiceConfiguration.class) public class SimpleMailService implements MessageService { @Reference(cardinality = ReferenceCardinality.MANDATORY, policy = ReferencePolicy.DYNAMIC, policyOption = ReferencePolicyOption.GREEDY) private volatile MailBuilder mailBuilder; @Reference(cardinality = ReferenceCardinality.MANDATORY, policy = ReferencePolicy.DYNAMIC, policyOption = ReferencePolicyOption.GREEDY) private volatile ThreadPoolManager threadPoolManager; // the ThreadPool used for sending mails private ThreadPool threadPool; private final Logger logger = LoggerFactory.getLogger(SimpleMailService.class); public SimpleMailService() { } @Activate private void activate(final SimpleMailServiceConfiguration configuration) { logger.debug("activate"); configure(configuration); } @Modified private void modified(final SimpleMailServiceConfiguration configuration) { logger.debug("modified"); configure(configuration); } @Deactivate protected void deactivate() { logger.info("deactivate"); threadPoolManager.release(threadPool); threadPool = null; } private void configure(final SimpleMailServiceConfiguration configuration) { threadPoolManager.release(threadPool); threadPool = threadPoolManager.get(configuration.threadpoolName()); } @Override public CompletableFuture<Result> send(@Nonnull final String message, @Nonnull final String recipient) { return send(message, recipient, Collections.emptyMap()); } @Override public CompletableFuture<Result> send(@Nonnull final String message, @Nonnull final String recipient, @Nonnull final Map data) { return CompletableFuture.supplyAsync(() -> sendMail(message, recipient, data, mailBuilder), runnable -> threadPool.submit(runnable)); } private MailResult sendMail(final String message, final String recipient, final Map data, final MailBuilder mailBuilder) { try { final Email email = mailBuilder.build(message, recipient, data); final String messageId = email.send(); logger.info("mail '{}' sent", messageId); final byte[] bytes = MailUtil.toByteArray(email); return new MailResult(bytes); } catch (EmailException | MessagingException | IOException e) { throw new CompletionException(e); } } }