public static void stamp(final HasAuditableUserIdentity hasAuditableUserIdentity,
                             final HasAuditInfo hasAuditInfo) {
        final long now = System.currentTimeMillis();
        final String userIdentityForAudit = hasAuditableUserIdentity.getUserIdentityForAudit();

        if (hasAuditInfo.getCreateTimeMs() == null) {
            hasAuditInfo.setCreateTimeMs(now);
        }
        if (hasAuditInfo.getCreateUser() == null) {
            hasAuditInfo.setCreateUser(userIdentityForAudit);
        }
        hasAuditInfo.setUpdateTimeMs(now);
        hasAuditInfo.setUpdateUser(userIdentityForAudit);
    }
Stamp {@code hasAuditInfo} with the create/update user/time, with the user identity
provided by {@code hasAuditableUserIdentity}.
stroom-util/src/main/java/stroom/util/AuditUtil.java