Re: throwing exceptions on instantiation

From:
Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>
Newsgroups:
comp.lang.java.help
Date:
Fri, 09 May 2008 07:55:17 -0700
Message-ID:
<482465b7$0$3246$7836cce5@newsrazor.net>
thufir wrote:

The makeGuest is working fine, probably because the data is fine. If the
constructor of Guest throws a DataException, though, I wouldn't want
makeGuest to return a new Guest! I'm not quite sure what it should do,
if not that, though...

Should I try makeGuest first? Would it make sense to have a tryMakeGuest
() method?

Just don't catch the exception in makeGuest. Let it propagate up to
whoever calls makeGuest.

thufir@arrakis:~/bcit-comp2611-project1$
thufir@arrakis:~/bcit-comp2611-project1$
thufir@arrakis:~/bcit-comp2611-project1$ cat src/a00720398/util/
FileUtil.java
/**
 * FileUtil.java
 */

package a00720398.util;

import java.util.*;
import java.io.*;
import a00720398.data.*;

public abstract class FileUtil {

        public static Guest makeGuest(List<String> guestData)throws
DataException{
                try{
                        String[] data = guestData.toArray(new String
[guestData.size()]);
                        Guest guest = new Guest(data);
                        return guest;
                } catch (DataException e) {
                        e.printStackTrace();
                }
                return new Guest();
        }

        public static List<Guest> loadGuests(){
                List<Guest> guests = new ArrayList<Guest>();

          File file = new File("Guests.txt");

                try {
                        Scanner scanner = new Scanner(file);
                        while (scanner.hasNextLine()) {
                                List<String> guestData = new
ArrayList<String>();
                                String line = scanner.nextLine();
                                Scanner lineScanner = new Scanner(line);
                                lineScanner.useDelimiter("\t");
                                while (lineScanner.hasNext()) {
                                        String part = lineScanner.next();
                                        guestData.add(part);
                                        if (!lineScanner.hasNext()) {
                                                try{
                                                        Guest guest =
makeGuest(guestData);
                                                        guests.add(guest);
                                                } catch (DataException e){
                                                        e.printStackTrace
();
                                                }
                                        }
                                }
                        }
                }catch (FileNotFoundException e) {
                        e.printStackTrace();
                }
                return guests;
        }

}
thufir@arrakis:~/bcit-comp2611-project1$


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