Version: 9.3.16.v20170120 |

Configuring JNDI
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## Configuring JNDI

### Configuring JNDI env-entries

Sometimes it is useful to pass configuration information to a webapp at runtime that you either cannot or cannot conveniently code into a `web.xml` env-entry. In such cases, you can use the `org.eclipse.jetty.plus.jndi.EnvEntry` class, and even override an entry of the same name in `web.xml`.

    <New class="org.eclipse.jetty.plus.jndi.EnvEntry">
      <Arg></Arg>
      <Arg>mySpecialValue</Arg>
      <Arg type="java.lang.Integer">4000</Arg>
      <Arg type="boolean">true</Arg>
    </New>

This example defines a virtual `env-entry` called `mySpecialValue` with value `4000` that is scoped to the JVM. It is put into JNDI at `java:comp/env/mySpecialValue` for every web app deployed. Moreover, the boolean argument indicates that this value overrides an `env-entry` of the same name in `web.xml`. If you don’t want to override, omit this argument, or set it to `false`.

The Servlet Specification allows binding only the following object types to an `env-entry`:

- java.lang.String
- java.lang.Integer
- java.lang.Float
- java.lang.Double
- java.lang.Long
- java.lang.Short
- java.lang.Character
- java.lang.Byte
- java.lang.Boolean

That being said, Jetty is a little more flexible and allows you to also bind custom POJOs, `javax.naming.References` and `javax.naming.Referenceables`. Be aware that if you take advantage of this feature, your web application is not portable.

To use the `env-entry` configured above, use code in your `servlet/filter/etc.`, such as:

    import javax.naming.InitialContext;

    public class MyClass {

      public void myMethod() {

        InitialContext ic = new InitialContext();
        Integer mySpecialValue = (Integer)ic.lookup("java:comp/env/mySpecialValue");
        ...
      }
    }

### Configuring resource-refs and resource-env-refs

You can configure any type of resource that you want to refer to in a `web.xml` file as a `resource-ref` or `resource-env-ref`, using the `org.eclipse.jetty.plus.jndi.Resource` type of naming entry. You provide the scope, the name of the object (relative to `java:comp/env`) and a POJO instance or a `javax.naming.Reference` instance or `javax.naming.Referenceable` instance.

The J2EE Specification recommends storing DataSources in `java:comp/env/jdbc`, JMS connection factories under `java:comp/env/jms`, JavaMail connection factories under `java:comp/env/mail` and URL connection factories under `java:comp/env/url`.

For example:

Table 12.1. DataSource Declaration Conventions

Resource Type | Name in `jetty.xml` | Environment Lookup
--- | --- | ---
javax.sql.DataSource | jdbc/myDB | java:comp/env/jdbc/myDB
javax.jms.QueueConnectionFactory | jms/myQueue | java:comp/env/jms/myQueue
javax.mail.Session | mail/myMailService | java:comp/env/mail/myMailService

### Configuring DataSources

Here is an example of configuring a `javax.sql.DataSource`. Jetty can use any DataSource implementation available on its classpath. In this example, the DataSource is from the Derby relational database, but you can use any implementation of a `javax.sql.DataSource`. This example configures it as scoped to a web app with the id of wac:

    <Configure id='wac' class="org.eclipse.jetty.webapp.WebAppContext">
      <New id="myds" class="org.eclipse.jetty.plus.jndi.Resource">
        <Arg><Ref refid="wac"/></Arg>
        <Arg>jdbc/myds</Arg>
        <Arg>
          <New class="org.apache.derby.jdbc.EmbeddedDataSource">
            <Set name="DatabaseName">test</Set>
            <Set name="createDatabase">create</Set>
          </New>
        </Arg>
      </New>
    </Configure>

The code above creates an instance of `org.apache.derby.jdbc.EmbeddedDataSource`, calls the two setter methods `setDatabaseName("test"),` and `setCreateDatabase("create"),` and binds it into the JNDI scope for the web app. If you do not have the appropriate `resource-ref` set up in your `web.xml`, it is available from application lookups as `java:comp/env/jdbc/myds`.

Here’s an example `web.xml` declaration for the datasource above:

    <resource-ref>
      <res-ref-name>jdbc/myds</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
    </resource-ref>

To look up your DataSource in your `servlet/filter/etc.`:

    import javax.naming.InitialContext;
    import javax.sql.DataSource;

    public class MyClass {

      public void myMethod() {

        InitialContext ic = new InitialContext();
        DataSource myDS = (DataSource)ic.lookup("java:comp/env/jdbc/myds");

        ...
      }
    }

> ### Note

> Careful! When configuring Resources, ensure that the type of object you configure matches the type of object you expect to look up in `java:comp/env`. For database connection factories, this means that the object you register as a Resource must implement the `javax.sql.DataSource` interface.

For more examples of datasource configurations, see Datasource Examples.

### Configuring JMS Queues, Topics and ConnectionFactories

Jetty can bind any implementation of the JMS destinations and connection factories. You just need to ensure the implementation Jars are available on Jetty’s classpath. Here is an example of binding an ActiveMQ in-JVM connection factory:

    <Configure id='wac' class="org.eclipse.jetty.webapp.WebAppContext">
      <New id="cf" class="org.eclipse.jetty.plus.jndi.Resource">
        <Arg><Ref refid='wac'/></Arg>
        <Arg>jms/connectionFactory</Arg>
        <Arg>
          <New class="org.apache.activemq.ActiveMQConnectionFactory">
            <Arg>vm://localhost?broker.persistent=false</Arg>
          </New>
        </Arg>
      </New>
    </Configure>

The entry in `web.xml` would be:

    <resource-ref>
      <res-ref-name>jms/connectionFactory</res-ref-name>
      <res-type>javax.jms.ConnectionFactory</res-type>
      <res-auth>Container</res-auth>
    </resource-ref>

TODO: put in an example of a QUEUE from progress demo

### Configuring Mail

Jetty also provides infrastructure for access to `javax.mail.Sessions` from within an application:

    <Configure id='wac' class="org.eclipse.jetty.webapp.WebAppContext">
      <New id="mail" class="org.eclipse.jetty.plus.jndi.Resource">
        <Arg><Ref refid="wac"/></Arg>
        <Arg>mail/Session</Arg>
        <Arg>
          <New class="org.eclipse.jetty.jndi.factories.MailSessionReference">
            <Set name="user">fred</Set>
            <Set name="password">OBF:1xmk1w261z0f1w1c1xmq</Set>
            <Set name="properties">
              <New class="java.util.Properties">
                <Put name="mail.smtp.host">XXX</Put>
                <Put name="mail.from">me@me</Put>
                <Put name="mail.debug">true</Put>
              </New>
            </Set>
          </New>
        </Arg>
      </New>
    </Configure>

This setup creates an instance of the `org.eclipse.jetty.jndi.factories.MailSessionReference` class, calls it’s setter methods to set up the authentication for the mail system, and populates a set of Properties, setting them on the `MailSessionReference` instance. The result is that an application can look up `java:comp/env/mail/Session` at runtime and obtain access to a `javax.mail.Session` that has the necessary configuration to permit it to send email via SMTP.

> ### Tip

> You can set the password to be plain text, or use Jetty’s Secure Password Obfuscation (OBF:) mechanism to make the config file a little more secure from prying eyes. Remember that you cannot use the other Jetty encryption mechanisms of MD5 and Crypt because they do not allow you to recover the original password, which the mail system requires.

### Configuring XA Transactions

If you want to perform distributed transactions with your resources, you need a transaction manager that supports the JTA interfaces, and that you can look up as `java:comp/UserTransaction` in your webapp. Jetty does not ship with one as standard, but you can plug in the one you prefer. You can configure a transaction manager using the JNDI Transaction object in a Jetty config file. The following example configures the Atomikos transaction manager:

    <New id="tx" class="org.eclipse.jetty.plus.jndi.Transaction">
      <Arg>
        <New class="com.atomikos.icatch.jta.J2eeUserTransaction"/>
      </Arg>
    </New>

### Configuring Links

Generally, the name you set for your `Resource` should be the same name you use for it in `web.xml`. For example:

In a context xml file:

    <Configure id='wac' class="org.eclipse.jetty.webapp.WebAppContext">
      <New id="myds" class="org.eclipse.jetty.plus.jndi.Resource">
        <Arg><Ref refid="wac"/></Arg>
        <Arg>jdbc/mydatasource</Arg>
        <Arg>
          <New class="org.apache.derby.jdbc.EmbeddedDataSource">
            <Set name="DatabaseName">test</Set>
            <Set name="createDatabase">create</Set>
          </New>
        </Arg>
      </New>
    </Configure>

In a `web.xml` file:

    <resource-ref>
      <res-ref-name>jdbc/mydatasource</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
      <injection-target>
        <injection-target-class>com.acme.JNDITest</injection-target-class>
        <injection-target-name>myDatasource</injection-target-name>
      </injection-target>
    </resource-ref>

However, you can refer to it in `web.xml` by a different name, and link it to the name in your `org.eclipse.jetty.plus.jndi.Resource` by using an `org.eclipse.jetty.plus.jndi.Link`. For the example above, you can refer to the `jdbc/mydatasource` resource as `jdbc/mydatasource1` as follows:

In a context xml file declare `jdbc/mydatasource`:

    <Configure id='wac' class="org.eclipse.jetty.webapp.WebAppContext">
      <New id="myds" class="org.eclipse.jetty.plus.jndi.Resource">
        <Arg><Ref refid="wac"/></Arg>
        <Arg>jdbc/mydatasource</Arg>
        <Arg>
          <New class="org.apache.derby.jdbc.EmbeddedDataSource">
            <Set name="DatabaseName">test</Set>
            <Set name="createDatabase">create</Set>
          </New>
        </Arg>
      </New>
    </Configure>

Then in a `WEB-INF/jetty-env.xml` file, link the name `jdbc/mydatasource` to the name you want to reference it as in `web.xml`, which in this case is `jdbc/mydatasource1`:

    <New id="map1" class="org.eclipse.jetty.plus.jndi.Link">
      <Arg><Ref refid='wac'/></Arg>
      <Arg>jdbc/mydatasource1</Arg> <!-- name in web.xml -->
      <Arg>jdbc/mydatasource</Arg>  <!-- name in container environment -->
    </New>

Now you can refer to `jdbc/mydatasource1` in the `web.xml` like this:

    <resource-ref>
      <res-ref-name>jdbc/mydatasource1</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
      <injection-target>
        <injection-target-class>com.acme.JNDITest</injection-target-class>
        <injection-target-name>myDatasource</injection-target-name>
      </injection-target>
    </resource-ref>

This can be useful when you cannot change a JNDI resource directly in the `web.xml` but need to link it to a specific resource in your deployment environment.

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