/*
 * MailManager: This implements a simple email manager.
 */

public class MailManager {
	private EmailMessage[ ] msgs;		// the messages
	private int nMsgs;					// current number of messages
	
	public MailManager( int max ) {
		msgs = new EmailMessage[max];
		nMsgs = 0;
	}
	
	public boolean isFull( ) { return (nMsgs >= msgs.length); }

	public boolean addMsg( EmailMessage m ) {
		if ( isFull( ) ) return false;
		msgs[nMsgs++] = new EmailMessage( m );
		return true;
	}
	
	public boolean deleteMsg( int d ) {
		if ( d < 0 || d > msgs.length ) return false;
		for ( int j = d+1; j < nMsgs; j++ )
			msgs[j-1] = msgs[j];
		nMsgs--;
		return true;
	}
	
	public void clear( ) {
		for ( int i = 0; i < nMsgs; i++ )		// unlink objects
			msgs[i] = null;
		nMsgs = 0;
	}
	
	public String toString( ) {
		String result = "Mailbox: ";
		if ( nMsgs == 0 ) return result + "empty";
		for ( int i = 0; i < nMsgs; i++ )
			result = result + "\n  " + msgs[i];
		return result;
	}
	
	public EmailMessage[ ] getMessages( ) {
		EmailMessage[ ] result = new EmailMessage[nMsgs];
		for (int i = 0; i < nMsgs; i++) {
			result[i] = new EmailMessage( msgs[i] );
		}
		return result;
	}
	
	public static void main( String[ ] args ) {
		
									// create a new email manager
		MailManager myMail = new MailManager( 5 );
									// initialize by adding 2 messages
		myMail.addMsg( new EmailMessage( "john@notReal.com", "Hi Everybody" ) );
		myMail.addMsg( new EmailMessage( "rose@fantasy.com", "I hate spam" ) );
		
		System.out.println( "Initial mailbox:" );
		System.out.println( myMail );
									// add a message
		myMail.addMsg( new EmailMessage( "pete@imaginary.com", "Me too" ) );
		System.out.println( "After addition:" );
		System.out.println( myMail );
		
		myMail.deleteMsg( 0 );		// delete the first message
		System.out.println( "After deletion:" );
		System.out.println( myMail );
		
									// retrieve messages
		EmailMessage[ ] myMessages = myMail.getMessages( );

		System.out.println( "Retrieved Messages:" );
		for ( int i = 0; i < myMessages.length; i++ )
			System.out.println( myMessages[i] );

		myMail.clear( );			// clear the mailbox
		System.out.println( "After clearing:" );
		System.out.println( myMail );
	}
}

class EmailMessage {
	private String addr;		// email address
	private String body;		// message body
	
	public EmailMessage( String a, String b )
	{ addr = new String( a ); body = new String( b ); }
	
	public EmailMessage( EmailMessage e)
	{ addr = new String( e.addr ); body = new String( e.body ); }
	
	public String toString( )
	{ return "From: <" + addr + "> Body: [" + body + "]"; }
}