Jetty/Reference/jetty.xml syntax

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{{Jetty Reference |introduction = The Jetty XML syntax is a straightforward mapping of XML elements to the Java API. Any getter, setter, or method can be invoked in the XML configuration files.

Contents

Basic Example

Here is an example of a file which uses the Jetty XML syntax (the example is extracted from etc/jetty.xml, available from your distribution, so it may look familiar):

  <?xml version="1.0"?>
  <!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://www.eclipse.org/jetty/configure.dtd">
  <!-- root element -->
  <Configure id="Server" class="org.eclipse.jetty.server.Server">
    <!-- using a setter on the server class -->
    <Set name="ThreadPool">
      <!-- creating a new object, and customizing it after creation -->
      <New class="org.eclipse.jetty.util.thread.QueuedThreadPool">
        <Set name="minThreads">10</Set>
      </New>
    </Set>
 
    <!-- calling a non-setter/non-getter class, with arguments -->
    <Call name="addConnector">
      <Arg>
          <New class="org.eclipse.jetty.server.nio.SelectChannelConnector">
            <Set name="host"><SystemProperty name="jetty.host" /></Set>
             ....
          </New>
      </Arg>
    </Call>
  </Configure>

Overview

DTD and Parsing

The document type descriptor (DTD) describes all valid elements that can be used. The first two lines must reference the DTD, and you must substitute the appropriate class for the object you are trying to configure. See the appropriate jetty-*.xml references.

Jetty XML files are parsed by the org.eclipse.jetty.xml.XmlConfiguration class using the configure.dtd descriptor.

Method Calls

Java objects are configured by a sequence of <New>, <Set>, <Put> and <Call> elements:

<Set name="Test">value</Set>
obj.setTest("value");
<Put  name="Test">value</Put>
obj.put("Test","value");
<Call name="test"><Arg>value</Arg></Call>
obj.test("value");
<New class="com.acme.MyStuff"><Arg/></New>
new com.acme.MyStuff();

Coercing Arguments to a Type

Values are coerced to match method arguments on a best effort approach, but explicit types may also be specified with the type attribute. Supported values for type are:

String, Character, Short, Byte, Integer, Long, Boolean, Float, Double, char, short, byte, int, long, boolean, float, double, URL, InetAddress, InetAddrPort, void

For Java classes, you may use either the fully qualified class name, or just the class name.

Referring to a Class

If you do not specify the classname, Jetty will assume you are calling the method on this. Otherwise, use the class attribute to specify the fully-qualified class name of an object to be configured. (You must always specify the class of the root Configure element.)

Referring to an Object

You can use the id attribute to store a reference to this object when first creating or referring to this object. You can then use the [[#[1] </source>

This is equivalent to:

foo = getXFoo();
foo.setTest("1, 2, 3");

Ref versus nested elements

Here is an example of the difference in syntax between using the Ref element, and nesting method calls. Both are exactly equivalent:

<!-- using Ref in conjunction with Get -->
<Configure id="Server" class="org.eclipse.jetty.server.Server">
  <Get id="Logger" class="org.eclipse.jetty.util.log.Log" name="log"/>
  <Ref id="Logger">
    <Set name="debugEnabled">true</Set>
  </Ref>
</Configure>
<!-- calling the setter directly on the object returned by Get -->
<Configure id="Server" class="org.eclipse.jetty.server.Server">
  <Get class="org.eclipse.jetty.util.log.Log" name="log">
    <Set name="debugEnabled">true</Set>
  </Get>
</Configure>

Here is a more practical example, taken from the handler configuration section in etc/jetty.xml:

<Set name="handler">
  <New id="Handlers" class="org.eclipse.jetty.server.handler.HandlerCollection">
    <Set name="handlers">
      <Array type="org.eclipse.jetty.server.Handler">
        <Item>
          <!-- create a new instance of a ContextHandlerCollection named "Contexts" -->
          <New id="Contexts" class="org.eclipse.jetty.server.handler.ContextHandlerCollection"/>
        </Item>
        <Item>
          <New id="DefaultHandler" class="org.eclipse.jetty.server.handler.DefaultHandler"/>
        </Item>
        <Item>
          <!-- create a new instance of a RequestLogHandler named "RequestLog"--->
          <New id="RequestLog" class="org.eclipse.jetty.server.handler.RequestLogHandler"/>
        </Item>
      </Array>
    </Set>
  </New>
</Set>
 
<Call name="addBean">
  <Arg>
    <New class="org.eclipse.jetty.deploy.ContextDeployer">
      <!-- pass in the ContextHandlerCollection object ("Contexts") that was created earlier, as an argument -->
      <Set name="contexts"><Ref id="Contexts"/></Set>
    </New>
  </Arg>
</Call>
 
<!-- configure the RequestLogHandler object ("RequestLog") that we created earlier -->
<Ref id="RequestLog">
  ....
</Ref>

<Array>

An Array element allows the creation of a new array.

Attributes

type 
(optional), specify what types of items the array can contain
id 
(optional), unique identifier you can use to refer to the array later on

Can Contain

<Item>

Examples

Basic example

 <Array type="java.lang.String">
   <Item>value0</Item>
   <Item><New class="java.lang.String"><Arg>value1</Arg></New></Item>
 </Array>

This is equivalent to:

String[] a = new String[] { "value0", new String("value1") };

<Item>

An Item element defines an entry for Array and Map elements.

Attributes

type 
(optional), force the types of value.
id 
(optional), unique identifier which can be used to refer to this item later on

Can Contain

value text, <Get>, <Call>, <New>, <Ref>, <Array>, <Map>, <SystemProperty>, <Property>

<Map>

A Map element allows the creation of a new HashMap and to populate it with (key, value) pairs.

Attributes

id 
(optional), unique identifier you can use to refer to the map later on

Can Contain

Entry

Examples

Basic example

<Map>
  <Entry>
    <Item>keyName</Item>
    <Item><New class="java.lang.String"><Arg>value1</Arg></New></Item>
  </Entry>
</Map>

This is equivalent to:

Map m = new HashMap();
m.put("keyName", new String("value1"));

<Entry>

An Entry element contains a key-value <Item> pair for a Map.

Can Contain

Item

<SystemProperty>

Attributes

Can Contain

Examples

<Property>

Attributes

Can Contain

Examples

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