org.neo4j.cluster.com.message.Message Maven / Gradle / Ivy
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/*
* Copyright (c) 2018-2020 "Graph Foundation"
* Graph Foundation, Inc. [https://graphfoundation.org]
*
* Copyright (c) 2002-2018 "Neo4j,"
* Neo4j Sweden AB [http://neo4j.com]
*
* This file is part of ONgDB Enterprise Edition. The included source
* code can be redistributed and/or modified under the terms of the
* GNU AFFERO GENERAL PUBLIC LICENSE Version 3
* (http://www.fsf.org/licensing/licenses/agpl-3.0.html) as found
* in the associated LICENSE.txt file.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*/
package org.neo4j.cluster.com.message;
import java.io.Serializable;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
/**
* Message for state machines which can be sent out to instances in the cluster as well.
*
* These are typically produced and consumed by a {@link org.neo4j.cluster.statemachine.StateMachine}.
*/
public class Message
implements Serializable
{
private static final long serialVersionUID = 7043669983188264476L;
public static Message to( MESSAGETYPE messageType, URI to )
{
return to( messageType, to, null );
}
public static Message to( MESSAGETYPE messageType, URI to,
Object payload )
{
return new Message<>( messageType, payload ).setHeader( HEADER_TO, to.toString() );
}
public static Message respond( MESSAGETYPE messageType,
Message message, Object payload )
{
return message.hasHeader( Message.HEADER_FROM ) ? new Message<>( messageType, payload )
.setHeader( HEADER_TO, message.getHeader( Message.HEADER_FROM ) ) : internal( messageType, payload );
}
public static Message internal( MESSAGETYPE message )
{
return internal( message, null );
}
public static Message internal( MESSAGETYPE message, Object payload )
{
return new Message<>( message, payload );
}
public static Message timeout( MESSAGETYPE message,
Message causedBy )
{
return timeout( message, causedBy, null );
}
public static Message timeout( MESSAGETYPE message,
Message causedBy, Object payload )
{
Message timeout = causedBy.copyHeadersTo( new Message<>( message, payload ),
Message.HEADER_CONVERSATION_ID, Message.HEADER_CREATED_BY );
int timeoutCount = 0;
if ( causedBy.hasHeader( HEADER_TIMEOUT_COUNT ) )
{
timeoutCount = Integer.parseInt( causedBy.getHeader( HEADER_TIMEOUT_COUNT ) ) + 1;
}
timeout.setHeader( HEADER_TIMEOUT_COUNT, "" + timeoutCount );
return timeout;
}
// Standard headers
public static final String HEADER_CONVERSATION_ID = "conversation-id";
public static final String HEADER_CREATED_BY = "created-by";
public static final String HEADER_TIMEOUT_COUNT = "timeout-count";
public static final String HEADER_FROM = "from";
public static final String HEADER_TO = "to";
public static final String HEADER_INSTANCE_ID = "instance-id";
// Should be present only in configurationRequest messages. Value is a comma separated list of instance ids.
// Added in 3.0.9.
public static final String DISCOVERED = "discovered";
private MESSAGETYPE messageType;
private Object payload;
private Map headers = new HashMap<>();
protected Message( MESSAGETYPE messageType, Object payload )
{
this.messageType = messageType;
this.payload = payload;
}
public MESSAGETYPE getMessageType()
{
return messageType;
}
@SuppressWarnings( "unchecked" )
public T getPayload()
{
return (T) payload;
}
public Message setHeader( String name, String value )
{
if ( value == null )
{
throw new IllegalArgumentException( String.format( "Header %s may not be set to null", name ) );
}
headers.put( name, value );
return this;
}
public boolean hasHeader( String name )
{
return headers.containsKey( name );
}
public boolean isInternal()
{
return !headers.containsKey( Message.HEADER_TO );
}
public String getHeader( String name )
throws IllegalArgumentException
{
String value = getHeader( name, null );
if ( value == null )
{
throw new IllegalArgumentException( "No such header:" + name );
}
return value;
}
public String getHeader( String name, String defaultValue )
{
String value = headers.get( name );
if ( value == null )
{
return defaultValue;
}
return value;
}
public Message copyHeadersTo( Message message,
String... names )
{
if ( names.length == 0 )
{
for ( Map.Entry header : headers.entrySet() )
{
if ( !message.hasHeader( header.getKey() ) )
{
message.setHeader( header.getKey(), header.getValue() );
}
}
}
else
{
for ( String name : names )
{
String value = headers.get( name );
if ( value != null && !message.hasHeader( name ) )
{
message.setHeader( name, value );
}
}
}
return message;
}
@Override
public boolean equals( Object o )
{
if ( this == o )
{
return true;
}
if ( o == null || getClass() != o.getClass() )
{
return false;
}
Message message = (Message) o;
if ( headers != null ? !headers.equals( message.headers ) : message.headers != null )
{
return false;
}
if ( messageType != null ? !messageType.equals( message.messageType ) : message.messageType != null )
{
return false;
}
return payload != null ? payload.equals( message.payload ) : message.payload == null;
}
@Override
public int hashCode()
{
int result = messageType != null ? messageType.hashCode() : 0;
result = 31 * result + (payload != null ? payload.hashCode() : 0);
result = 31 * result + (headers != null ? headers.hashCode() : 0);
return result;
}
@Override
public String toString()
{
return messageType.name() + headers + (payload instanceof String ? ": " + payload : "");
}
}