MINA Component
Deprecated
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This component is deprecated as the Apache Mina 1.x project is EOL. Instead use MINA2 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:
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<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
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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
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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:
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{snippet:id=e1|lang=java|url=camel/trunk/components/camel-mina/src/test/java/org/apache/camel/component/mina/MinaConsumerTest.java} |
As the sample is part of a unit test, we test it by sending some data to it on port 6200.
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{snippet:id=e2|lang=java|url=camel/trunk/components/camel-mina/src/test/java/org/apache/camel/component/mina/MinaConsumerTest.java} |
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.
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{snippet:id=e3|lang=java|url=camel/trunk/components/camel-mina/src/test/java/org/apache/camel/component/mina/MinaConsumerTest.java} |
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.
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{snippet:id=e4|lang=java|url=camel/trunk/components/camel-mina/src/test/java/org/apache/camel/component/mina/MinaConsumerTest.java} |
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:
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<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:
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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:
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{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-mina/src/test/resources/org/apache/camel/component/mina/SpringMinaEndpointTest-context.xml} |
And then we can refer to our endpoint directly in the route, as follows:
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{snippet:id=e2|lang=xml|url=camel/trunk/components/camel-mina/src/test/resources/org/apache/camel/component/mina/SpringMinaEndpointTest-context.xml} |
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:
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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
.
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If using the |
For instance, the example below will send a keep-alive message after 10 seconds of inactivity:
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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.
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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:
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<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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