API Key implementation in Apache Shiro

I have Java web application which implemented Apache shiro Authentication & Authorization.

Now i need to implement API Key to the existing project (which has apache shiro). Please help me on implementation part. Even i could not find any documentation

PS:: We have already implemented 3 different types of Custom Realm(jdbc,ldap,Pac4jRealm) but now struggling to implement the API key concept with Apache Shiro.

I resolved the above issue by extending the JDBCRealm,see the below example code

public class APIRealm extends JdbcRealm {
    @Override
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {

        SimpleAuthorizationInfo info = null;
        AuthAPIInfo authInfo = null;
        try {
        String apiKey= (String) principals.getPrimaryPrincipal();
        authInfo=fetchAPIKeyInfo(apiName);

        // Do all the other stuff like checking for Authorization and setting it to token

        } catch (Exception e) {
            insertAPILogActivity(authInfo, "User not authorized");
        }
        return info;

    }

private AuthAPIInfo fetchAPIKeyInfo(String apiKeyName) {
    //Connect to Database using JDBC connection and validate the API Key and return the AuthAPIInfo
}

}

Add the above realm in shiro.ini

apiRealm=com.example.APIRealm
securityManager.realms=$apiRealm