[[stax-component]]
== StAX Component

*Available as of Camel version 2.9*

The StAX component allows messages to be process through a SAX
http://download.oracle.com/javase/6/docs/api/org/xml/sax/ContentHandler.html[ContentHandler]. +
Another feature of this component is to allow to iterate over JAXB
records using StAX, for example using the Splitter
EIP.

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

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-stax</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

### URI format

[source,java]
--------------------------
stax:content-handler-class
--------------------------

example:

[source,java]
-----------------------------------
stax:org.superbiz.FooContentHandler
-----------------------------------

From *Camel 2.11.1* onwards you can lookup a
`org.xml.sax.ContentHandler` bean from the Registry
using the # syntax as shown:

[source,java]
---------------
stax:#myHandler
---------------

### Options


// component options: START
The StAX component has no options.
// component options: END



// endpoint options: START
The StAX endpoint is configured using URI syntax:

----
stax:contentHandlerClass
----

with the following path and query parameters:

==== Path Parameters (1 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *contentHandlerClass* | *Required* The FQN class name for the ContentHandler implementation to use. |  | String
|===


==== Query Parameters (1 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *synchronous* (advanced) | Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). | false | boolean
|===
// endpoint options: END
// spring-boot-auto-configure options: START
=== Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

[source,xml]
----
<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-stax-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>
----


The component supports 2 options, which are listed below.



[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *camel.component.stax.enabled* | Enable stax component | true | Boolean
| *camel.component.stax.resolve-property-placeholders* | Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. | true | Boolean
|===
// spring-boot-auto-configure options: END



### Usage of a content handler as StAX parser

The message body after the handling is the handler itself.

Here an example:

[source,java]
--------------------------------------------------------------------------------------------------------
from("file:target/in")
  .to("stax:org.superbiz.handler.CountingHandler") 
  // CountingHandler implements org.xml.sax.ContentHandler or extends org.xml.sax.helpers.DefaultHandler
  .process(new Processor() {
    @Override
    public void process(Exchange exchange) throws Exception {
        CountingHandler handler = exchange.getIn().getBody(CountingHandler.class);
        // do some great work with the handler
    }
  });
--------------------------------------------------------------------------------------------------------

### Iterate over a collection using JAXB and StAX

First we suppose you have JAXB objects.

For instance a list of records in a wrapper object:

[source,java]
-------------------------------------------------
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "records")
public class Records {
    @XmlElement(required = true)
    protected List<Record> record;

    public List<Record> getRecord() {
        if (record == null) {
            record = new ArrayList<Record>();
        }
        return record;
    }
}
-------------------------------------------------

and

[source,java]
---------------------------------------------------------
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "record", propOrder = { "key", "value" })
public class Record {
    @XmlAttribute(required = true)
    protected String key;

    @XmlAttribute(required = true)
    protected String value;

    public String getKey() {
        return key;
    }

    public void setKey(String key) {
        this.key = key;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}
---------------------------------------------------------

Then you get a XML file to process:

[source,xml]
-------------------------------------------------------
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<records>
  <record value="v0" key="0"/>
  <record value="v1" key="1"/>
  <record value="v2" key="2"/>
  <record value="v3" key="3"/>
  <record value="v4" key="4"/>
  <record value="v5" key="5"/>
</record>
-------------------------------------------------------

The StAX component provides an `StAXBuilder` which can be used when
iterating XML elements with the Camel Splitter

[source,java]
------------------------------------------
from("file:target/in")
    .split(stax(Record.class)).streaming()
        .to("mock:records");
------------------------------------------

Where `stax` is a static method on
`org.apache.camel.component.stax.StAXBuilder` which you can static
import in the Java code. The stax builder is by default namespace aware
on the XMLReader it uses. From *Camel 2.11.1* onwards you can turn this
off by setting the boolean parameter to false, as shown below:

[source,java]
-------------------------------------------------
from("file:target/in")
    .split(stax(Record.class, false)).streaming()
        .to("mock:records");
-------------------------------------------------

#### The previous example with XML DSL

The example above could be implemented as follows in XML DSL

### See Also

* Configuring Camel
* Component
* Endpoint
* Getting Started
