How do you know which XML parameters a Spring configuration tag has?

Question

I was just reading an article that showed the following Spring Security XML configuration:

<authentication-provider>  
  <password-encoder hash="sha" />  
  <jdbc-user-service data-source-ref="dataSource" />  
</authentication-provider>

I wondered if password-encoder could take some combination of parameters that would make it use SHA-256. I easily found the Java constructor for the ShaPasswordEncoder, but how can I tell whether the password-encoder tag takes the argument for the Java object?

In general, how can one tell what the tags and parameters for Spring configuration are?

For example, how do I know which that ShaPasswordEncoder goes with "password-encoder" (if indeed it does)?

Answer 1

You look at the XML Schema. For example:

<xs:attribute name="hash">
  <xs:annotation>
    <xs:documentation>
      Defines the hashing algorithm used on user passwords. We recommend
      strongly against using MD4, as it is a very weak hashing algorithm.
    </xs:documentation>
  </xs:annotation>
  <xs:simpleType>
    <xs:restriction base="xs:token">
      <xs:enumeration value="plaintext"/>
      <xs:enumeration value="sha"/>
      <xs:enumeration value="sha-256"/>
      <xs:enumeration value="md5"/>
      <xs:enumeration value="md4"/>
      <xs:enumeration value="{sha}"/>
      <xs:enumeration value="{ssha}"/>
    </xs:restriction>
  </xs:simpleType>
</xs:attribute>

So, you should do this:

<authentication-provider>  
  <password-encoder hash="sha-256" />  
  <jdbc-user-service data-source-ref="dataSource" />  
</authentication-provider>