org.springframework.messaging.support.GenericMessage Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.messaging.support;
import java.io.Serializable;
import java.util.Map;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
/**
* An implementation of {@link Message} with a generic payload.
* Once created, a GenericMessage is immutable.
*
* @author Mark Fisher
* @since 4.0
* @param the payload type
* @see MessageBuilder
*/
public class GenericMessage implements Message, Serializable {
private static final long serialVersionUID = 4268801052358035098L;
private final T payload;
private final MessageHeaders headers;
/**
* Create a new message with the given payload.
* @param payload the message payload (never {@code null})
*/
public GenericMessage(T payload) {
this(payload, new MessageHeaders(null));
}
/**
* Create a new message with the given payload and headers.
* The content of the given header map is copied.
* @param payload the message payload (never {@code null})
* @param headers message headers to use for initialization
*/
public GenericMessage(T payload, Map headers) {
this(payload, new MessageHeaders(headers));
}
/**
* A constructor with the {@link MessageHeaders} instance to use.
* Note: the given {@code MessageHeaders} instance is used
* directly in the new message, i.e. it is not copied.
* @param payload the message payload (never {@code null})
* @param headers message headers
*/
public GenericMessage(T payload, MessageHeaders headers) {
Assert.notNull(payload, "Payload must not be null");
Assert.notNull(headers, "MessageHeaders must not be null");
this.payload = payload;
this.headers = headers;
}
@Override
public T getPayload() {
return this.payload;
}
@Override
public MessageHeaders getHeaders() {
return this.headers;
}
@Override
public boolean equals(@Nullable Object other) {
if (this == other) {
return true;
}
if (!(other instanceof GenericMessage)) {
return false;
}
GenericMessage otherMsg = (GenericMessage) other;
// Using nullSafeEquals for proper array equals comparisons
return (ObjectUtils.nullSafeEquals(this.payload, otherMsg.payload) && this.headers.equals(otherMsg.headers));
}
@Override
public int hashCode() {
// Using nullSafeHashCode for proper array hashCode handling
return (ObjectUtils.nullSafeHashCode(this.payload) * 23 + this.headers.hashCode());
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder(getClass().getSimpleName());
sb.append(" [payload=");
if (this.payload instanceof byte[]) {
sb.append("byte[").append(((byte[]) this.payload).length).append("]");
}
else {
sb.append(this.payload);
}
sb.append(", headers=").append(this.headers).append("]");
return sb.toString();
}
}