public void setUserArn(String userArn) {
        this.userArn = userArn;
    }
<p>
The Amazon Resource Name (ARN) of an individual environment member to get information about. If no value is
specified, information about all environment members are returned.
</p>

@param userArn
       The Amazon Resource Name (ARN) of an individual environment member to get information about. If no value
       is specified, information about all environment members are returned.
aws-java-sdk-cloud9/src/main/java/com/amazonaws/services/cloud9/model/DescribeEnvironmentMembershipsRequest.java