The mina: component is a transport for working with Apache MINA
mina:tcp://hostname[:port][?options] mina:udp://hostname[:port][?options] mina:vm://hostname[:port][?options]
From Apache Camel 1.3 onwards 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&...
Table 60 lists the Mina uri options:
Table 60. URI options
Option | Default Value | Description |
---|---|---|
codec
|
null
| As of 1.3, you can refer to a named
ProtocolCodecFactory instance
in your Registry
such as your Spring
ApplicationContext , which is
then used for the marshalling. |
codec
|
null
| Apache Camel
2.0: You must use the
# notation to look up your
codec in the Registry. For example, use
#myCodec to look up a bean
with the id value,
myCodec . |
disconnect
|
false
| Apache Camel 2.3: Whether or not to disconnect(close) from Mina session right after use. Can be used for both consumer and producer. |
textline
|
false
| Only used for TCP. If no codec is specified, you
can use this flag in 1.3 or later to indicate a text
line based codec; if not specified or the value is
false , then Object
Serialization is assumed over TCP. |
textlineDelimiter
|
DEFAULT
| Apache Camel
1.6.0/2.0 Only used for TCP and if
textline=true.
Sets the text line delimiter to use. Possible values
are: DEFAULT ,
AUTO ,
WINDOWS ,
UNIX or
MAC . If none provided,
Apache Camel will use DEFAULT . This
delimiter is used to mark the end of text. |
sync
|
true
| As of Apache Camel 1.3, you can configure the
exchange pattern to be either InOnly (default) or
InOut. Setting sync=true means a
synchronous exchange (InOut), where the client can
read the response from MINA (the exchange Out
message). The default value has changed in Apache Camel
1.5 to true . In older releases,
the default value is false . |
lazySessionCreation
| See description | As of Apache Camel 1.3, sessions can be lazily
created to avoid exceptions, if the remote server is
not up and running when the Apache Camel producer is
started. From Apache Camel 2.0 onwards, the default
is true . In Apache Camel 1.x, the
default is false . |
timeout
|
30000
| As of Apache Camel 1.3, 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. The timeout is only used for Mina producer. |
encoding
| JVM Default | As of Apache Camel 1.3, you can configure the encoding (a charset name) to use for the TCP textline codec and the UDP protocol. If not provided, Apache Camel will use the JVM default Charset. |
transferExchange
|
false
| Only used for TCP. As of 1.3, 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. Apache Camel
will exclude any non-serializable objects and log it
at WARN level. |
minaLogger
|
false
| As of Apache Camel 1.3, you can enable the
Apache MINA logging filter. Apache MINA uses
slf4j logging at
INFO level to log all input
and output. |
filters
|
null
|
As of 2.0, you can set a list of Mina IoFilters to register. The
|
encoderMaxLineLength
|
-1
| As of Apache Camel 2.1, you can set the textline
protocol encoder max line length. By default the
default value of Mina itself is used which are
Integer.MAX_VALUE . |
decoderMaxLineLength
|
-1
| As of Apache Camel 2.1, you can set the textline protocol decoder max line length. By default the default value of Mina itself is used which are 1024. |
allowDefaultCodec
|
true
| 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. |
disconnectOnNoReply
|
true
| Apache Camel 2.3: If sync is enabled then this option dictates MinaConsumer if it should disconnect where there is no reply to send back. |
noReplyLogLevel
|
WARN
| Apache Camel
2.3: If sync is enabled this option
dictates MinaConsumer which logging level to use
when logging a there is no reply to send back.
Values are: FATAL, ERROR, INFO, DEBUG,
OFF . |
In Apache Camel 2.0 the codec option must use #
notation
for lookup of the codec bean in the Registry. In Apache Camel 2.0 the lazySessionCreation option now defaults to
true
.
In Apache Camel 1.5 the sync
option has changed its default value from false
to true
, as we felt it was confusing for
end-users when they used Mina to call remote servers and Apache
Camel wouldn't wait for the response.
In Apache Camel 1.4 or later
codec=textline
is no longer supported. Use
the textline=true
option instead.
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.
In this sample, Apache 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:
from("mina:tcp://localhost:6200?textline=true&sync=false").to("mock:result");
As the sample is part of a unit test, we test it by sending some data to it on port 6200.
MockEndpoint mock = getMockEndpoint("mock:result"); mock.expectedBodiesReceived("Hello World"); template.sendBody("mina:tcp://localhost:6200?textline=true&sync=false", "Hello World"); assertMockEndpointsSatisfied();
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.
from("mina:tcp://localhost:6201?textline=true&sync=true").process(new Processor() { public void process(Exchange exchange) throws Exception { String body = exchange.getIn().getBody(String.class); exchange.getOut().setBody("Bye " + body); } });
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.
String response = (String)template.requestBody("mina:tcp://localhost:6201?textline=true&sync=true", "World"); assertEquals("Bye World", response);
XML 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" }
Available as of Apache Camel 2.0
Configuration of Mina endpoints is now 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:
<!-- Creating mina endpoints is a bit complex so we reuse MinaComponnet as a factory bean to create our endpoint, this is the easiest to do --> <bean id="myMinaFactory" class="org.apache.camel.component.mina.MinaComponent"> <!-- we must provide a camel context so we refer to it by its id --> <constructor-arg index="0" ref="myCamel"/> </bean> <!-- This is our mina endpoint configured with Spring, we will use the factory above to create it for us. The goal is to invoke the createEndpoint method with the mina configuration parameter we defined using the constructor-arg option --> <bean id="myMinaEndpoint" factory-bean="myMinaFactory" factory-method="createEndpoint"> <!-- and here we can pass it our configuration --> <constructor-arg index="0" ref="myMinaConfig"/> </bean> <!-- this is our mina configuration with plain properties --> <bean id="myMinaConfig" class="org.apache.camel.component.mina.MinaConfiguration"> <property name="protocol" value="tcp"/> <property name="host" value="localhost"/> <property name="port" value="1234"/> <property name="sync" value="false"/> </bean>
And then we can refer to our endpoint directly in the route, as follows:
<route> <!-- here we route from or mina endpoint we have defined above --> <from ref="myMinaEndpoint"/> <to uri="mock:result"/> </route>
Available as of Apache Camel 1.6.1
When acting as a server you sometimes want to close the session
when, for example, a client conversion is finished. To instruct
Apache 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(MinaConsumer.HEADER_CLOSE_SESSION_WHEN_COMPLETE, true); } });
Available since Apache 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
.
Available since Apache Camel 2.0
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
.
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 Apache Camel may use a request-reply scheme, the endpoint as a
client would like to drop some message, such as a 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 XML 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>