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.james.webadmin.service; import java.util.Optional; import java.util.function.Consumer; import javax.inject.Inject; import javax.mail.MessagingException; import org.apache.commons.lang3.tuple.Pair; import org.apache.james.mailrepository.api.MailKey; import org.apache.james.mailrepository.api.MailRepository; import org.apache.james.mailrepository.api.MailRepositoryPath; import org.apache.james.mailrepository.api.MailRepositoryStore; import org.apache.james.queue.api.MailQueue; import org.apache.james.queue.api.MailQueueFactory; import org.apache.james.util.OptionalUtils; import org.apache.james.util.streams.Iterators; import org.apache.mailet.Mail; import com.github.fge.lambdas.Throwing; public class ReprocessingService { public static class MissingKeyException extends RuntimeException { MissingKeyException(MailKey key) { super(key.asString() + " can not be found"); } } static class Reprocessor { private final MailQueue mailQueue; private final Optional<String> targetProcessor; Reprocessor(MailQueue mailQueue, Optional<String> targetProcessor) { this.mailQueue = mailQueue; this.targetProcessor = targetProcessor; } private void reprocess(MailRepository repository, Mail mail) { try { targetProcessor.ifPresent(mail::setState); mailQueue.enQueue(mail); repository.remove(mail); } catch (Exception e) { throw new RuntimeException("Error encountered while reprocessing mail " + mail.getName(), e); } } } private final MailQueueFactory<?> mailQueueFactory; private final MailRepositoryStoreService mailRepositoryStoreService; @Inject public ReprocessingService(MailQueueFactory<?> mailQueueFactory, MailRepositoryStoreService mailRepositoryStoreService) { this.mailQueueFactory = mailQueueFactory; this.mailRepositoryStoreService = mailRepositoryStoreService; } public void reprocessAll(MailRepositoryPath path, Optional<String> targetProcessor, String targetQueue, Consumer<MailKey> keyListener) throws MailRepositoryStore.MailRepositoryStoreException, MessagingException { Reprocessor reprocessor = new Reprocessor(getMailQueue(targetQueue), targetProcessor); mailRepositoryStoreService.getRepositories(path) .forEach(Throwing.consumer( (MailRepository repository) -> Iterators.toStream(repository.list()).peek(keyListener) .map(Throwing.function(key -> Optional.ofNullable(repository.retrieve(key)))) .flatMap(OptionalUtils::toStream) .forEach(mail -> reprocessor.reprocess(repository, mail)))); } public void reprocess(MailRepositoryPath path, MailKey key, Optional<String> targetProcessor, String targetQueue) throws MailRepositoryStore.MailRepositoryStoreException, MessagingException { Reprocessor reprocessor = new Reprocessor(getMailQueue(targetQueue), targetProcessor); Pair<MailRepository, Mail> mailPair = mailRepositoryStoreService.getRepositories(path) .map(Throwing .function(repository -> Pair.of(repository, Optional.ofNullable(repository.retrieve(key))))) .filter(pair -> pair.getRight().isPresent()) .map(pair -> Pair.of(pair.getLeft(), pair.getRight().get())).findFirst() .orElseThrow(() -> new MissingKeyException(key)); reprocessor.reprocess(mailPair.getKey(), mailPair.getValue()); } private MailQueue getMailQueue(String targetQueue) { return mailQueueFactory.getQueue(targetQueue) .orElseThrow(() -> new RuntimeException("Can not find queue " + targetQueue)); } }