public void setValidFrom(Date validFrom) {
        this.validFrom = validFrom;
    }
Sets the day after which this account becomes valid and usable. Account
validity begins at midnight of this day. Any time information within
the provided Date object will be ignored.

@param validFrom
    The day after which this account becomes valid and usable, or null
    if this restriction does not apply.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/user/UserModel.java