Mina

Since Camel 1.0

Deprecated

This component is deprecated as the Apache Mina 1.x project is EOL. Instead use Mina 2 or Netty instead.

The mina: component is a transport for working with Apache MINA

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-mina</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI format

mina:tcp://hostname[:port][?options]
mina:udp://hostname[:port][?options]
mina:vm://hostname[:port][?options]

You can specify a codec in the Registry using the codec option. If you are using TCP and no codec is specified then the textline flag is used to determine if text line based codec or object serialization should be used instead. By default the object serialization is used.

For UDP if no codec is specified the default uses a basic ByteBuffer based codec.

The VM protocol is used as a direct forwarding mechanism in the same JVM. See the MINA VM-Pipe API documentation for details.

A Mina producer has a default timeout value of 30 seconds, while it waits for a response from the remote server.

In normal use, camel-mina only supports marshalling the body content—message headers and exchange properties are not sent.

 However, the option, *transferExchange*, does allow you to transfer the
exchange itself over the wire. See options below.

You can append query options to the URI in the following format, ?option=value&option=value&…​

Options

The Mina component supports 2 options, which are listed below.

Name Description Default Type

configuration (advanced)

To use the shared mina configuration.

MinaConfiguration

resolveProperty Placeholders (advanced)

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

boolean

The Mina endpoint is configured using URI syntax:

mina:protocol:host:port

with the following path and query parameters:

Path Parameters (3 parameters):

Name Description Default Type

protocol

Required Protocol to use

String

host

Required Hostname to use. Use localhost or 0.0.0.0 for local server as consumer. For producer use the hostname or ip address of the remote server.

String

port

Required Port number

int

Query Parameters (21 parameters):

Name Description Default Type

disconnect (common)

Whether or not to disconnect(close) from Mina session right after use. Can be used for both consumer and producer.

false

boolean

minaLogger (common)

You can enable the Apache MINA logging filter. Apache MINA uses slf4j logging at INFO level to log all input and output.

false

boolean

sync (common)

Setting to set endpoint as one-way or request-response.

true

boolean

timeout (common)

You can configure the timeout that specifies how long to wait for a response from a remote server. The timeout unit is in milliseconds, so 60000 is 60 seconds.

30000

long

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

clientMode (consumer)

If the clientMode is true, mina consumer will connect the address as a TCP client.

false

boolean

disconnectOnNoReply (consumer)

If sync is enabled then this option dictates MinaConsumer if it should disconnect where there is no reply to send back.

true

boolean

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer)

Sets the exchange pattern when the consumer creates an exchange.

ExchangePattern

noReplyLogLevel (consumer)

If sync is enabled this option dictates MinaConsumer which logging level to use when logging a there is no reply to send back.

WARN

LoggingLevel

lazySessionCreation (producer)

Sessions can be lazily created to avoid exceptions, if the remote server is not up and running when the Camel producer is started.

true

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

transferExchange (advanced)

Only used for TCP. You can transfer the exchange over the wire instead of just the body. The following fields are transferred: In body, Out body, fault body, In headers, Out headers, fault headers, exchange properties, exchange exception. This requires that the objects are serializable. Camel will exclude any non-serializable objects and log it at WARN level.

false

boolean

allowDefaultCodec (codec)

The mina component installs a default codec if both, codec is null and textline is false. Setting allowDefaultCodec to false prevents the mina component from installing a default codec as the first element in the filter chain. This is useful in scenarios where another filter must be the first in the filter chain, like the SSL filter.

true

boolean

codec (codec)

To use a custom minda codec implementation.

ProtocolCodecFactory

decoderMaxLineLength (codec)

To set the textline protocol decoder max line length. By default the default value of Mina itself is used which are 1024.

1024

int

encoderMaxLineLength (codec)

To set the textline protocol encoder max line length. By default the default value of Mina itself is used which are Integer.MAX_VALUE.

-1

int

encoding (codec)

You can configure the encoding (a charset name) to use for the TCP textline codec and the UDP protocol. If not provided, Camel will use the JVM default Charset

String

filters (codec)

You can set a list of Mina IoFilters to use.

List

textline (codec)

Only used for TCP. If no codec is specified, you can use this flag to indicate a text line based codec; if not specified or the value is false, then Object Serialization is assumed over TCP.

false

boolean

textlineDelimiter (codec)

Only used for TCP and if textline=true. Sets the text line delimiter to use. If none provided, Camel will use DEFAULT. This delimiter is used to mark the end of text.

TextLineDelimiter

Using a custom codec

See the Mina documentation how to write your own codec. To use your custom codec with camel-mina, you should register your codec in the Registry; for example, by creating a bean in the Spring XML file. Then use the codec option to specify the bean ID of your codec. See HL7 that has a custom codec.

Sample with sync=false

In this sample, Camel exposes a service that listens for TCP connections on port 6200. We use the textline codec. In our route, we create a Mina consumer endpoint that listens on port 6200:

As the sample is part of a unit test, we test it by sending some data to it on port 6200.

Sample with sync=true

In the next sample, we have a more common use case where we expose a TCP service on port 6201 also use the textline codec. However, this time we want to return a response, so we set the sync option to true on the consumer.

Then we test the sample by sending some data and retrieving the response using the template.requestBody() method. As we know the response is a String, we cast it to String and can assert that the response is, in fact, something we have dynamically set in our processor code logic.

Sample with Spring DSL

Spring DSL can, of course, also be used for Mina. In the sample below we expose a TCP server on port 5555:

   <route>
     <from uri="mina:tcp://localhost:5555?textline=true"/>
     <to uri="bean:myTCPOrderHandler"/>
  </route>

In the route above, we expose a TCP server on port 5555 using the textline codec. We let the Spring bean with ID, myTCPOrderHandler, handle the request and return a reply. For instance, the handler bean could be implemented as follows:

    public String handleOrder(String payload) {
        ...
        return "Order: OK"
   }

Configuring Mina endpoints using Spring bean style

Configuration of Mina endpoints is possible using regular Spring bean style configuration in the Spring DSL.

However, in the underlying Apache Mina toolkit, it is relatively difficult to set up the acceptor and the connector, because you can not use simple setters. To resolve this difficulty, we leverage the MinaComponent as a Spring factory bean to configure this for us. If you really need to configure this yourself, there are setters on the MinaEndpoint to set these when needed.

The sample below shows the factory approach:

And then we can refer to our endpoint directly in the route, as follows:

Closing Session When Complete

When acting as a server you sometimes want to close the session when, for example, a client conversion is finished. To instruct Camel to close the session, you should add a header with the key CamelMinaCloseSessionWhenComplete set to a boolean true value.

For instance, the example below will close the session after it has written the bye message back to the client:

        from("mina:tcp://localhost:8080?sync=true&textline=true").process(new Processor() {
            public void process(Exchange exchange) throws Exception {
                String body = exchange.getIn().getBody(String.class);
                exchange.getOut().setBody("Bye " + body);
                exchange.getOut().setHeader(MinaConstants.MINA_CLOSE_SESSION_WHEN_COMPLETE, true);
            }
        });

Get the IoSession for message

Available since Camel 2.1 You can get the IoSession from the message header with this key MinaEndpoint.HEADER_MINA_IOSESSION, and also get the local host address with the key MinaEndpoint.HEADER_LOCAL_ADDRESS and remote host address with the key MinaEndpoint.HEADER_REMOTE_ADDRESS.

Configuring Mina filters

Filters permit you to use some Mina Filters, such as SslFilter. You can also implement some customized filters. Please note that codec and logger are also implemented as Mina filters of type, IoFilter. Any filters you may define are appended to the end of the filter chain; that is, after codec and logger.

If using the SslFilter you need to add the mina-filter-ssl JAR to the classpath.

For instance, the example below will send a keep-alive message after 10 seconds of inactivity:

public class KeepAliveFilter extends IoFilterAdapter {
    @Override
    public void sessionCreated(NextFilter nextFilter, IoSession session)
            throws Exception {
        session.setIdleTime(IdleStatus.BOTH_IDLE, 10);

        nextFilter.sessionCreated(session);
    }

    @Override
    public void sessionIdle(NextFilter nextFilter, IoSession session,
            IdleStatus status) throws Exception {
        session.write("NOOP"); // NOOP is a FTP command for keep alive
        nextFilter.sessionIdle(session, status);
    }
}

As Camel Mina may use a request-reply scheme, the endpoint as a client would like to drop some message, such as greeting when the connection is established. For example, when you connect to an FTP server, you will get a 220 message with a greeting (220 Welcome to Pure-FTPd). If you don’t drop the message, your request-reply scheme will be broken.

public class DropGreetingFilter extends IoFilterAdapter {

    @Override
    public void messageReceived(NextFilter nextFilter, IoSession session,
            Object message) throws Exception {
        if (message instanceof String) {
            String ftpMessage = (String) message;
            // "220" is given as greeting. "200 Zzz" is given as a response to "NOOP" (keep alive)
            if (ftpMessage.startsWith("220") || or ftpMessage.startsWith("200 Zzz")) {
                // Dropping greeting
                return;
            }
        }
        nextFilter.messageReceived(session, message);
    }
}

Then, you can configure your endpoint using Spring DSL:

<bean id="myMinaFactory" class="org.apache.camel.component.mina.MinaComponent">
    <constructor-arg index="0" ref="camelContext" />
</bean>

<bean id="myMinaEndpoint"
      factory-bean="myMinaFactory"
      factory-method="createEndpoint">
    <constructor-arg index="0" ref="myMinaConfig"/>
</bean>

<bean id="myMinaConfig" class="org.apache.camel.component.mina.MinaConfiguration">
    <property name="protocol" value="tcp" />
    <property name="host" value="localhost" />
    <property name="port" value="2121" />
    <property name="sync" value="true" />
    <property name="minaLogger" value="true" />
    <property name="filters" ref="listFilters"/>
</bean>

<bean id="listFilters" class="java.util.ArrayList" >
    <constructor-arg>
        <list value-type="org.apache.mina.common.IoFilter">
            <bean class="com.example.KeepAliveFilter"/>
            <bean class="com.example.DropGreetingFilter"/>
        </list>
    </constructor-arg>
</bean>
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