Tomcat, JAAS and config file

As you know Tomcat is able to use JAAS Login Module for Realm authentication. But if you use standard implementation you should start Tomcat with parameter -Djava.security.auth.login.config==$CATALINA_HOME/conf/jaas.config, where jaas.config is your JAAS configuration file.

So I extended JAASRealm with jaasConfigFile attribute.

package my.realm;

import org.apache.catalina.realm.JAASRealm;

/**
 * This is customization of JAASRealm, created for taking ability of setting JAAS Config File via realm properties.
 * @author Sergey Vinogradov
 */
public class GDJaasRealm extends JAASRealm {
    private String jaasConfigFile;

    public void init() {
        System.setProperty("java.security.auth.login.config", jaasConfigFile);
        super.init();

    }

    public String getJaasConfigFile() {
        return jaasConfigFile;
    }

    public void setJaasConfigFile(String jaasConfigFile) {
        this.jaasConfigFile = jaasConfigFile;
    }
}

Thus you may declare this Realm at server.xml instead of org.apache.catalina.realm.JAASRealm

<Realm className="my.realm.GDJaasRealm"                 
          userClassNames="my.ldap.UserPrincipal"
          roleClassNames="my.ldap.RolePrincipal"       
          appName="my_app"
          jaasConfigFile="D:\ldap-jaas.conf"/>