Tomcat application context.xml

Question

This is my problem:
I've been programming my own implementation of a Realm.
within I want to access a <Environment>-Entry situated in
a customized Context.xml :
<Context docBase="${catalina.home}/webapps/slide"
privileged="true" antiResourceLocking="false"
antiJARLocking="false" useNaming="true">
<Environment name="test" type="java.lang.String"
value="C:/user.xml"/>
          <Realm className="MyRealm"/>
</Context>
What do I need to do to gain access.
When I declare the variable in <GlobalNamingResources> there is no problem accessing it.

Answer 1

To clarify I add portions of my configuration files:
<b>hibernate.cfg.xml</b> fragment:
<property name="connection.datasource">
  java:comp/env/jdbc/cname
</property>
<property name="dialect">
  net.sf.hibernate.dialect.OracleDialect
</property>
<property name="connection.driver_class">
  oracle.jdbc.driver.OracleDriver
</property>
<property name="transaction.factory_class">
  net.sf.hibernate.transaction.JDBCTransactionFactory
</property> <b>web.xml</b> fragment:
<resource-ref>
  <description>DataSource</description>
  <res-ref-name>jdbc/cname</res-ref-name>
  <res-type>javax.sql.DataSource</res-type>
  <res-auth>Container</res-auth>
</resource-ref>What I want to put inside <b>tomcat context application definition</b>:
<Resource name="jdbc/cname" scope="Shareable" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/cname">
  <parameter>
    <name>factory</name>
    <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
  </parameter>
  <parameter>
    <name>url</name>
    <value>jdbc:oracle:thin:@server:1521:SID</value>
  </parameter>
  <parameter>
    <name>driverClassName</name>
    <value>oracle.jdbc.driver.OracleDriver</value>
  </parameter>
  <parameter>
    <name>username</name>
    <value>name</value>
  </parameter>
  <parameter>
    <name>password</name>
    <value>pass</value>
  </parameter>
  <parameter>
    <name>maxWait</name>
    <value>3000</value>
  </parameter>
  <parameter>
    <name>maxIdle</name>
    <value>100</value>
  </parameter>
  <parameter>
    <name>maxActive</name>
    <value>10</value>
  </parameter>
</ResourceParams>
<Realm className="org.apache.catalina.realm.DataSourceRealm"
   dataSourceName="jdbc/cname"
   localDataSource="true"
   digest="MD5"
   userTable="usr" userNameCol="user" userCredCol="passwd"
   userRoleTable="usrrol" roleNameCol="rol" />