package cs$1302.$hw$06$; import java.time.LocalDate; $/**$ Represents an Email message in the cs$1302$ mock $*$ eLC application. $**$ @author Brad Barnes $*$ @version $1\mathrm{.}1$; Mar $22019*/$ public class Email $\{/**$ Email address of the recipient. $*/$ private String recipient; $/**$ Email address of the sender$.*/$ private String sender; $/**$ Date sent. $*/$ private LocalDate sendDate; $/**$ Contents of the Email message. $*/$ private String contents; $/***$ Constructs a new $\{$@code Email$\}$ object. All parameters must be specified $*$ and non$-$null. $\{$@code java.lang.String$\}$ parameters must not be empty and $*$ any $\{$@code java.lang.String$\}$ parameter representing an email address $*$ must be a valid email address. $**$ @throws NullPointerException if any argument is $\{$@code null$\}.*$ @throws IllegalArgumentException if any of the $\{$@code java.lang.String$\}*$ arguments are empty or if the email addresses are invalid. $*$ @param recipient email address of the recipient. $*$ @param sender email address of the sender$.*$ @param sendDate $\{$@code java.time.LocalDate$\}$ reference representing $*$ the date the email was sent. $*$ @param contents the message contents $($message body$).*/$ public Email$($String recipient, String sender$,$ LocalDate sendDate$,$ String contents$)\{$ checkNull$("$Email Constructor", contents, sendDate$,$ recipient, sender$)$; checkEmpty$("$Email Constructor", recipient, sender$,$ contents$)$; checkAddress$("$Email Constructor", recipient, sender$)$; this.sender $=$ sender; this.recipient $=$ recipient; this.sendDate $=$ sendDate; this.contents $=$ contents; $\}//$ Email $/***$ Returns the date that the Email was originally sent. $**$ @return the $\{$@code java.time.LocalDate$\}$ this $\{$@code Email$\}*$ was sent. $*/$ public LocalDate getDateSent$()\{$ return sendDate; $\}//$ getSendDate $/***$ Returns the email address of the recipient as a $*\{$@code java.lang.String$\}.*$ @return the email address of the recipient of this $*\{$@code Email$\}$ object. $*/$ public String getRecipient$()\{$ return recipient; $\}//$ getRecipient $/***$ Returns the email address of the sender as a $*\{$@code java.lang.String$\}.*$ @return the email address of the sender of this $*\{$@code Email$\}$ object. $*/$ public String getSender$()\{$ return sender; $\}//$ getSender $/***$ Returns the contents of this $\{$@code Email$\}$ as a $*\{$@code java.lang.String$\}.*$ @return the contents of this $\{$@code Email$\}$ object. $*/$ public String getContents$()\{$ return contents; $\}//$ getSender $/***$ Throws a $\{$@code NullPointerException$\}$ if any of the supplied values $*$ are $\{$@code null$\}.$ The method performs no actions if all values $*$ are not $\{$@code null$\}.**$ @param method The name of the calling method. $*$ @param values The values to verify. The number of values is variable $*$ and may be zero. $*$ @throws NullPointerException if any of the supplied values are $\{$@code null$\}*/$ private void checkNull$($String method, Object $...$ values$)\{$ for $($Object value: values$)\{$ if $($value $==$ null$)\{$ throw new NullPointerException$($method $+"$: Null Argument Provided"$)$; $\}//$ if $\}//$ for $\}//$ checkNull $/***$ Throws an IllegalArgumentException if any $\{$@code Strings$\}*$ in the varargs parameter, $\{$@code s$\}$ are empty. The $*$ method performs no actions if all values in $\{$@code s$\}*$ are non$-$null. $**$ @param method the name of the calling method. $*$ @param s varargs parameter containing all strings to verify $*$ @throws IllegalArgumentException if any element of parameter $*\{$@code s$\}$ is empty. $*/$ private void checkEmpty$($String method, String $...$ s$)\{$ for $($String str: s$)\{$ if $($str$.$equals$(""))\{$ throw new IllegalArgumentException$($method $+"$: Empty String Provided"$)$; $\}//$ if $\}//$ for $\}//$ checkEmpty $/***$ Throws an IllegalArgumentException if any $\{$@code Strings$\}*$ in the varargs parameter, $\{$@code s$\}$ do not contain a $*$ valid email address. This method considers an email address $*$ valid if it contains the $\{$@code @$\}$ symbol and a $\{$@code $.\}*$ somewhere after the $\{$@code @$\}.$ This method for checking $*$ validity would not hold up in a real$-$world system. For more $*$ information on accurately checking email validity, see $*$ the link below. $*$ The method performs no actions if all values in $\{$@code s$\}*$ contain