camel git commit: Added seda component docs to Gitbook

[ac...@apache.org]

Repository: camel
Updated Branches:
  refs/heads/master 4acb8ed7e -> 0de807d39


Added seda component docs to Gitbook


Project: http://git-wip-us.apache.org/repos/asf/camel/repo
Commit: http://git-wip-us.apache.org/repos/asf/camel/commit/0de807d3
Tree: http://git-wip-us.apache.org/repos/asf/camel/tree/0de807d3
Diff: http://git-wip-us.apache.org/repos/asf/camel/diff/0de807d3

Branch: refs/heads/master
Commit: 0de807d390d4fbea8837b958de5a258da6c494f7
Parents: 4acb8ed
Author: Andrea Cosentino <an...@gmail.com>
Authored: Fri Jun 17 11:46:53 2016 +0200
Committer: Andrea Cosentino <an...@gmail.com>
Committed: Fri Jun 17 11:46:53 2016 +0200

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 camel-core/src/main/docs/seda.adoc | 260 ++++++++++++++++++++++++++++++++
 docs/user-manual/en/SUMMARY.md     |   1 +
 2 files changed, 261 insertions(+)
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http://git-wip-us.apache.org/repos/asf/camel/blob/0de807d3/camel-core/src/main/docs/seda.adoc
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diff --git a/camel-core/src/main/docs/seda.adoc b/camel-core/src/main/docs/seda.adoc
new file mode 100644
index 0000000..6f60ec2
--- /dev/null
+++ b/camel-core/src/main/docs/seda.adoc
@@ -0,0 +1,260 @@
+[[SEDA-SEDAComponent]]
+SEDA Component
+~~~~~~~~~~~~~~
+
+The *seda:* component provides asynchronous
+http://www.eecs.harvard.edu/~mdw/proj/seda/[SEDA] behavior, so that
+messages are exchanged on a
+http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/BlockingQueue.html[BlockingQueue]
+and consumers are invoked in a separate thread from the producer.
+
+Note that queues are only visible within a _single_
+link:camelcontext.html[CamelContext]. If you want to communicate across
+`CamelContext` instances (for example, communicating between Web
+applications), see the link:vm.html[VM] component.
+
+This component does not implement any kind of persistence or recovery,
+if the VM terminates while messages are yet to be processed. If you need
+persistence, reliability or distributed SEDA, try using either
+link:jms.html[JMS] or link:activemq.html[ActiveMQ].
+
+TIP:*Synchronous*
+The link:direct.html[Direct] component provides synchronous invocation
+of any consumers when a producer sends a message exchange.
+
+[[SEDA-URIformat]]
+URI format
+^^^^^^^^^^
+
+[source,java]
+-----------------------
+seda:someName[?options]
+-----------------------
+
+Where *someName* can be any string that uniquely identifies the endpoint
+within the current link:camelcontext.html[CamelContext].
+
+You can append query options to the URI in the following format:
+`?option=value&option=value&\u2026`
+
+[[SEDA-Options]]
+Options
+^^^^^^^
+
+
+// component options: START
+The SEDA component supports 3 options which are listed below.
+
+
+
+{% raw %}
+[width="100%",cols="2s,1m,8",options="header"]
+|=======================================================================
+| Name | Java Type | Description
+| queueSize | int | Sets the default maximum capacity of the SEDA queue (i.e. the number of messages it can hold).
+| concurrentConsumers | int | Sets the default number of concurrent threads processing exchanges.
+| defaultQueueFactory | Exchange> | Sets the default queue factory.
+|=======================================================================
+{% endraw %}
+// component options: END
+
+
+
+// endpoint options: START
+The SEDA component supports 17 endpoint options which are listed below:
+
+{% raw %}
+[width="100%",cols="2s,1,1m,1m,5",options="header"]
+|=======================================================================
+| Name | Group | Default | Java Type | Description
+| name | common |  | String | *Required* Name of queue
+| size | common | 2147483647 | int | The maximum capacity of the SEDA queue (i.e. the number of messages it can hold).
+| bridgeErrorHandler | consumer | false | boolean | 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/ERROR level and ignored.
+| concurrentConsumers | consumer | 1 | int | Number of concurrent threads processing exchanges.
+| exceptionHandler | consumer (advanced) |  | ExceptionHandler | To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options is not in use. By default the consumer will deal with exceptions that will be logged at WARN/ERROR level and ignored.
+| limitConcurrentConsumers | consumer (advanced) | true | boolean | Whether to limit the number of concurrentConsumers to the maximum of 500. By default an exception will be thrown if an endpoint is configured with a greater number. You can disable that check by turning this option off.
+| multipleConsumers | consumer (advanced) | false | boolean | Specifies whether multiple consumers are allowed. If enabled you can use SEDA for Publish-Subscribe messaging. That is you can send a message to the SEDA queue and have each consumer receive a copy of the message. When enabled this option should be specified on every consumer endpoint.
+| pollTimeout | consumer (advanced) | 1000 | int | The timeout used when polling. When a timeout occurs the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.
+| purgeWhenStopping | consumer (advanced) | false | boolean | Whether to purge the task queue when stopping the consumer/route. This allows to stop faster as any pending messages on the queue is discarded.
+| blockWhenFull | producer | false | boolean | Whether a thread that sends messages to a full SEDA queue will block until the queue's capacity is no longer exhausted. By default an exception will be thrown stating that the queue is full. By enabling this option the calling thread will instead block and wait until the message can be accepted.
+| discardIfNoConsumers | producer | false | boolean | Whether the producer should discard the message (do not add the message to the queue) when sending to a queue with no active consumers. Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same time.
+| failIfNoConsumers | producer | false | boolean | Whether the producer should fail by throwing an exception when sending to a queue with no active consumers. Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same time.
+| timeout | producer | 30000 | long | Timeout (in milliseconds) before a SEDA producer will stop waiting for an asynchronous task to complete. You can disable timeout by using 0 or a negative value.
+| waitForTaskToComplete | producer | IfReplyExpected | WaitForTaskToComplete | Option to specify whether the caller should wait for the async task to complete or not before continuing. The following three options are supported: Always Never or IfReplyExpected. The first two values are self-explanatory. The last value IfReplyExpected will only wait if the message is Request Reply based. The default option is IfReplyExpected.
+| exchangePattern | advanced | InOnly | ExchangePattern | Sets the default exchange pattern when creating an exchange.
+| queue | advanced |  | BlockingQueue | Define the queue instance which will be used by the endpoint. This option is only for rare use-cases where you want to use a custom queue instance.
+| synchronous | advanced | false | boolean | Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).
+|=======================================================================
+{% endraw %}
+// endpoint options: END
+
+
+[[SEDA-ChoosingBlockingQueueimplementation]]
+Choosing BlockingQueue implementation
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*Available as of Camel 2.12*
+
+By default, the SEDA component always intantiates LinkedBlockingQueue,
+but you can use different implementation, you can reference your own
+BlockingQueue implementation, in this case the size option is not used
+
+[source,java]
+-----------------------------------------------------------
+<bean id="arrayQueue" class="java.util.ArrayBlockingQueue">
+<constructor-arg index="0" value="10" ><!-- size -->
+<constructor-arg index="1" value="true" ><!-- fairness -->
+</bean>
+<!-- ... and later -->
+<from>seda:array?queue=#arrayQueue</from>
+-----------------------------------------------------------
+
+Or you can reference a BlockingQueueFactory implementation, 3
+implementations are provided LinkedBlockingQueueFactory,
+ArrayBlockingQueueFactory and PriorityBlockingQueueFactory:
+
+[source,java]
+-----------------------------------------------------------------------------------------------------
+<bean id="priorityQueueFactory" class="org.apache.camel.component.seda.PriorityBlockingQueueFactory">
+<property name="comparator">
+<bean class="org.apache.camel.demo.MyExchangeComparator" />
+</property>
+</bean>
+<!-- ... and later -->
+<from>seda:priority?queueFactory=#priorityQueueFactory&size=100</from>
+-----------------------------------------------------------------------------------------------------
+
+[[SEDA-UseofRequestReply]]
+Use of Request Reply
+^^^^^^^^^^^^^^^^^^^^
+
+The link:seda.html[SEDA] component supports using
+link:request-reply.html[Request Reply], where the caller will wait for
+the link:async.html[Async] route to complete. For instance:
+
+[source,java]
+-------------------------------------------------------------------------
+from("mina:tcp://0.0.0.0:9876?textline=true&sync=true").to("seda:input");
+
+from("seda:input").to("bean:processInput").to("bean:createResponse");
+-------------------------------------------------------------------------
+
+In the route above, we have a TCP listener on port 9876 that accepts
+incoming requests. The request is routed to the `seda:input` queue. As
+it is a link:request-reply.html[Request Reply] message, we wait for the
+response. When the consumer on the `seda:input` queue is complete, it
+copies the response to the original message response.
+
+NOTE:*until 2.2: Works only with 2 endpoints*
+Using link:request-reply.html[Request Reply] over link:seda.html[SEDA]
+or link:vm.html[VM] only works with 2 endpoints. You *cannot* chain
+endpoints by sending to A -> B -> C etc. Only between A -> B. The reason
+is the implementation logic is fairly simple. To support 3+ endpoints
+makes the logic much more complex to handle ordering and notification
+between the waiting threads properly.
+This has been improved in *Camel 2.3* onwards, which allows you to chain
+as many endpoints as you like.
+
+[[SEDA-Concurrentconsumers]]
+Concurrent consumers
+^^^^^^^^^^^^^^^^^^^^
+
+By default, the SEDA endpoint uses a single consumer thread, but you can
+configure it to use concurrent consumer threads. So instead of thread
+pools you can use:
+
+[source,java]
+---------------------------------------------------------
+from("seda:stageName?concurrentConsumers=5").process(...)
+---------------------------------------------------------
+
+As for the difference between the two, note a _thread pool_ can
+increase/shrink dynamically at runtime depending on load, whereas the
+number of concurrent consumers is always fixed.
+
+[[SEDA-Threadpools]]
+Thread pools
+^^^^^^^^^^^^
+
+Be aware that adding a thread pool to a SEDA endpoint by doing something
+like:
+
+[source,java]
+---------------------------------------------
+from("seda:stageName").thread(5).process(...)
+---------------------------------------------
+
+Can wind up with two `BlockQueues`: one from the SEDA endpoint, and one
+from the workqueue of the thread pool, which may not be what you want.
+Instead, you might wish to configure a link:direct.html[Direct] endpoint
+with a thread pool, which can process messages both synchronously and
+asynchronously. For example:
+
+[source,java]
+-----------------------------------------------
+from("direct:stageName").thread(5).process(...)
+-----------------------------------------------
+
+You can also directly configure number of threads that process messages
+on a SEDA endpoint using the `concurrentConsumers` option.
+
+[[SEDA-Sample]]
+Sample
+^^^^^^
+
+In the route below we use the SEDA queue to send the request to this
+async queue to be able to send a fire-and-forget message for further
+processing in another thread, and return a constant reply in this thread
+to the original caller.
+
+Here we send a Hello World message and expects the reply to be OK.
+
+The "Hello World" message will be consumed from the SEDA queue from
+another thread for further processing. Since this is from a unit test,
+it will be sent to a `mock` endpoint where we can do assertions in the
+unit test.
+
+[[SEDA-UsingmultipleConsumers]]
+Using multipleConsumers
+^^^^^^^^^^^^^^^^^^^^^^^
+
+*Available as of Camel 2.2*
+
+In this example we have defined two consumers and registered them as
+spring beans.
+
+Since we have specified *multipleConsumers=true* on the seda foo
+endpoint we can have those two consumers receive their own copy of the
+message as a kind of pub-sub style messaging.
+
+As the beans are part of an unit test they simply send the message to a
+mock endpoint, but notice how we can use @Consume to consume from the
+seda queue.
+
+[[SEDA-Extractingqueueinformation.]]
+Extracting queue information.
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If needed, information such as queue size, etc. can be obtained without
+using JMX in this fashion:
+
+[source,java]
+-----------------------------------------------------
+SedaEndpoint seda = context.getEndpoint("seda:xxxx");
+int size = seda.getExchanges().size();
+-----------------------------------------------------
+
+[[SEDA-SeeAlso]]
+See Also
+^^^^^^^^
+
+* link:configuring-camel.html[Configuring Camel]
+* link:component.html[Component]
+* link:endpoint.html[Endpoint]
+* link:getting-started.html[Getting Started]
+
+* link:vm.html[VM]
+* link:disruptor.html[Disruptor]
+* link:direct.html[Direct]
+* link:async.html[Async]
+

http://git-wip-us.apache.org/repos/asf/camel/blob/0de807d3/docs/user-manual/en/SUMMARY.md
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diff --git a/docs/user-manual/en/SUMMARY.md b/docs/user-manual/en/SUMMARY.md
index 7efa196..7aa1c16 100644
--- a/docs/user-manual/en/SUMMARY.md
+++ b/docs/user-manual/en/SUMMARY.md
@@ -91,6 +91,7 @@
     * [Ref](ref.adoc)
     * [Rest](rest.adoc)
     * [Scheduler](scheduler.adoc)
+    * [Seda](seda.adoc)
 
 * Components
     * [Async Http Client (AHC)](ahc.adoc)