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Chapter 328. StAX Component

Available as of Camel version 2.9

The StAX component allows messages to be process through a SAX 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: 

<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>
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328.1. URI format
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stax:content-handler-class
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example: 

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

stax:#myHandler
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328.2. Options
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The StAX component has no options.

The StAX endpoint is configured using URI syntax: 

stax:contentHandlerClass
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with the following path and query parameters:

328.2.1. Path Parameters (1 parameters):
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Expand
NameDescriptionDefaultType

contentHandlerClass

Required The FQN class name for the ContentHandler implementation to use.

 

String

328.2.2. Query Parameters (1 parameters):
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Expand
NameDescriptionDefaultType

synchronous (advanced)

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

false

boolean

328.3. Spring Boot Auto-Configuration
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The component supports 2 options, which are listed below.

Expand
NameDescriptionDefaultType

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

328.4. Usage of a content handler as StAX parser
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The message body after the handling is the handler itself.

Here an example: 

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
    }
  });
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328.5. Iterate over a collection using JAXB and StAX
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First we suppose you have JAXB objects.

For instance a list of records in a wrapper object: 

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;
    }
}
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and 

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;
    }
}
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Then you get a XML file to process: 

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

from("file:target/in")
    .split(stax(Record.class)).streaming()
        .to("mock:records");
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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: 

from("file:target/in")
    .split(stax(Record.class, false)).streaming()
        .to("mock:records");
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328.5.1. The previous example with XML DSL
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The example above could be implemented as follows in XML DSL

328.6. See Also
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  • Configuring Camel
  • Component
  • Endpoint
  • Getting Started
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