Java tutorial
/* * Copyright 2002-2016 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 * * 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.springframework.integration.history; import java.io.Serializable; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.Iterator; import java.util.List; import java.util.ListIterator; import java.util.Properties; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.integration.IntegrationMessageHeaderAccessor; import org.springframework.integration.message.AdviceMessage; import org.springframework.integration.support.DefaultMessageBuilderFactory; import org.springframework.integration.support.MessageBuilderFactory; import org.springframework.integration.support.MutableMessage; import org.springframework.integration.support.MutableMessageBuilderFactory; import org.springframework.integration.support.context.NamedComponent; import org.springframework.messaging.Message; import org.springframework.messaging.support.ErrorMessage; import org.springframework.messaging.support.GenericMessage; import org.springframework.util.Assert; import org.springframework.util.StringUtils; /** * @author Mark Fisher * @author Artem Bilan * @since 2.0 */ @SuppressWarnings("serial") public final class MessageHistory implements List<Properties>, Serializable { private static final Log logger = LogFactory.getLog(MessageHistory.class); public static final String HEADER_NAME = "history"; public static final String NAME_PROPERTY = "name"; public static final String TYPE_PROPERTY = "type"; public static final String TIMESTAMP_PROPERTY = "timestamp"; private static final MessageBuilderFactory MESSAGE_BUILDER_FACTORY = new DefaultMessageBuilderFactory(); private final List<Properties> components; public static MessageHistory read(Message<?> message) { return message != null ? message.getHeaders().get(HEADER_NAME, MessageHistory.class) : null; } public static <T> Message<T> write(Message<T> message, NamedComponent component) { return write(message, component, MESSAGE_BUILDER_FACTORY); } @SuppressWarnings("unchecked") public static <T> Message<T> write(Message<T> message, NamedComponent component, MessageBuilderFactory messageBuilderFactory) { Assert.notNull(message, "Message must not be null"); Assert.notNull(component, "Component must not be null"); Properties metadata = extractMetadata(component); if (!metadata.isEmpty()) { MessageHistory previousHistory = message.getHeaders().get(HEADER_NAME, MessageHistory.class); List<Properties> components = (previousHistory != null) ? new ArrayList<Properties>(previousHistory) : new ArrayList<Properties>(); components.add(metadata); MessageHistory history = new MessageHistory(components); if (message instanceof MutableMessage) { message.getHeaders().put(HEADER_NAME, history); } else if (message instanceof ErrorMessage) { IntegrationMessageHeaderAccessor headerAccessor = new IntegrationMessageHeaderAccessor(message); headerAccessor.setHeader(HEADER_NAME, history); Throwable payload = ((ErrorMessage) message).getPayload(); ErrorMessage errorMessage = new ErrorMessage(payload, headerAccessor.toMessageHeaders()); message = (Message<T>) errorMessage; } else if (message instanceof AdviceMessage) { IntegrationMessageHeaderAccessor headerAccessor = new IntegrationMessageHeaderAccessor(message); headerAccessor.setHeader(HEADER_NAME, history); message = new AdviceMessage<T>(message.getPayload(), headerAccessor.toMessageHeaders(), ((AdviceMessage<?>) message).getInputMessage()); } else { if (!(message instanceof GenericMessage) && (messageBuilderFactory instanceof DefaultMessageBuilderFactory || messageBuilderFactory instanceof MutableMessageBuilderFactory)) { if (logger.isWarnEnabled()) { logger.warn("MessageHistory rebuilds the message and produces the result of the [" + messageBuilderFactory + "], not an instance of the provided type [" + message.getClass() + "]. Consider to supply a custom MessageBuilderFactory " + "to retain custom messages during MessageHistory tracking."); } } message = messageBuilderFactory.fromMessage(message).setHeader(HEADER_NAME, history).build(); } } return message; } private MessageHistory(List<Properties> components) { Assert.notEmpty(components, "component list must not be empty"); this.components = components; } @Override public int size() { return this.components.size(); } @Override public boolean isEmpty() { return this.components.isEmpty(); } @Override public boolean contains(Object o) { return this.components.contains(o); } @Override public boolean containsAll(Collection<?> c) { return this.components.containsAll(c); } @Override public Properties get(int index) { return this.components.get(index); } @Override public Iterator<Properties> iterator() { return Collections.unmodifiableList(this.components).iterator(); } @Override public ListIterator<Properties> listIterator() { return Collections.unmodifiableList(this.components).listIterator(); } @Override public ListIterator<Properties> listIterator(int index) { return Collections.unmodifiableList(this.components).listIterator(index); } @Override public List<Properties> subList(int fromIndex, int toIndex) { return Collections.unmodifiableList(this.components).subList(fromIndex, toIndex); } @Override public Object[] toArray() { return this.components.toArray(); } @Override public <T> T[] toArray(T[] a) { return this.components.toArray(a); } @Override public int indexOf(Object o) { return this.components.indexOf(o); } @Override public int lastIndexOf(Object o) { return this.components.lastIndexOf(o); } @Override public String toString() { List<String> names = new ArrayList<String>(); for (Properties p : this.components) { String name = p.getProperty(NAME_PROPERTY); if (name != null) { names.add(name); } } return StringUtils.collectionToCommaDelimitedString(names); } /* * Unsupported Operations */ @Override public boolean add(Properties e) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public void add(int index, Properties element) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public boolean addAll(Collection<? extends Properties> c) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public boolean addAll(int index, Collection<? extends Properties> c) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public Properties set(int index, Properties element) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public Properties remove(int index) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public boolean remove(Object o) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public boolean removeAll(Collection<?> c) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public boolean retainAll(Collection<?> c) { throw new UnsupportedOperationException("MessageHistory is immutable."); } @Override public void clear() { throw new UnsupportedOperationException("MessageHistory is immutable."); } private static Properties extractMetadata(NamedComponent component) { Entry entry = new Entry(); String name = component.getComponentName(); String type = component.getComponentType(); if (name != null && !name.startsWith("org.springframework.integration")) { entry.setName(name); if (type != null) { entry.setType(type); } } if (!entry.isEmpty()) { entry.setTimestamp(Long.toString(System.currentTimeMillis())); } return entry; } /** * Inner class for each Entry in the history. */ public static class Entry extends Properties { public String getName() { return this.getProperty(NAME_PROPERTY); } private void setName(String name) { this.setProperty(NAME_PROPERTY, name); } public String getType() { return this.getProperty(TYPE_PROPERTY); } private void setType(String type) { this.setProperty(TYPE_PROPERTY, type); } public String getTimestamp() { return this.getProperty(TIMESTAMP_PROPERTY); } private void setTimestamp(String timestamp) { this.setProperty(TIMESTAMP_PROPERTY, timestamp); } } }