public PutFileSystemPolicyRequest withFileSystemId(String fileSystemId) {
        setFileSystemId(fileSystemId);
        return this;
    }
<p>
The ID of the EFS file system that you want to create or update the <code>FileSystemPolicy</code> for.
</p>

@param fileSystemId
       The ID of the EFS file system that you want to create or update the <code>FileSystemPolicy</code> for.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-efs/src/main/java/com/amazonaws/services/elasticfilesystem/model/PutFileSystemPolicyRequest.java