Java enum for use across class

Question

I am having trouble declaring an enumeration for DB field types that I can use across all functions of a particular class. With the following code I get "cannot resolve USERNAME to a variable type":

public class SQL_access {

    public enum DBfields { BLANK, USERNAME, ID, PASSWORD, FIRSTNAME, LASTNAME }; 

    public boolean loginValidate( String username, String password ){

        String DBuser, DBpass;
        PreparedStatement table = connectToTable( "firstsql", "users");
        ResultSet row = table.executeQuery();;

        while(row.next()){
            DBuser = row.getString(USERNAME);
            if(DBuser.equals(username)){
                DBpass = row.getString(PASSWORD);
                break;
            }
        }
    }
};

jtahlborn · Accepted Answer · 2012-07-13 14:35:24Z

6

You need to use DBfields.USERNAME.

UPDATE:

in order to use with the getString(String) method, you need to use the name of the enum, like: Dbfields.USERNAME.name().

if you are using the enums only for the jdbc API access, you would be better off just using a String constant:

public static final String DBFIELD_USERNAME = "USERNAME";

edited Jul 13, 2012 at 14:35

answered Jul 13, 2012 at 14:30

jtahlborn

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3 Comments

Austin Over a year ago

I tried that, and get this error: The method getString(int) in the type ResultSet is not applicable for the arguments (SQL_access.DBfields)

Simulant Over a year ago

getString(xxx) needs an int as argument, not a String. Did it wrong in the first place, too. But updated my post now.

jtahlborn Over a year ago

@Simulant - there is both getString(int) (get by position) and getString(String) (get by column name).

bruno conde · Accepted Answer · 2012-07-13 14:46:35Z

3

You need to reference the enum Type: DBfields.USERNAME, or statically import the enum like:

import static mypackage.SQL_access.DBfields.*;

Also, in your case, this is not enough. You need to pass the column name -- a String -- or the column position -- an int -- to the ResultSet:

row.getString(DBfields.USERNAME.name());

Used like this, you loose the main advantage of enums which is it's static nature, but it can still be useful in other places in your code if you refer to these values as a "bag".

edited Jul 13, 2012 at 14:46

answered Jul 13, 2012 at 14:38

bruno conde

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Comments

Dan W · Accepted Answer · 2012-07-13 14:30:34Z

1

You should access the enum by using DBfields.USERNAME.

See the Oracle Docs for more information.

answered Jul 13, 2012 at 14:30

Dan W

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Comments

Andy Thomas · Accepted Answer · 2012-07-13 14:30:39Z

1

Try qualifying the enumerator with the enum type:

   while(row.next()){
        DBuser = row.getString( DBfields.USERNAME);
        if(DBuser.equals(username)){
            DBpass = row.getString( DBfields.PASSWORD);
            break;
        }
    }

answered Jul 13, 2012 at 14:30

Andy Thomas

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Comments

Woot4Moo · Accepted Answer · 2012-07-13 14:30:45Z

1

When you reference an enumeration it is always in this form EnumName.Field. In your example you need the following:

DBUser = row.getString(DBfields.USERNAME);  
DBpass=row.getString(DBfields.PASSWORD);

answered Jul 13, 2012 at 14:30

Woot4Moo

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Comments

Simulant · Accepted Answer · 2012-07-13 14:33:24Z

1

to access your enumbs use DBfields.USERNAME, but this will not help you, bacuse row.getString() needs an int as argument. Your Enumbs are of the Type DBFields not int. better use public static final int USERNAME = the int value here; and call with row.getString(USERNAME);.

answered Jul 13, 2012 at 14:33

Simulant

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2 Comments

Austin Over a year ago

thanks for the answer, but that's too messy =/ I'll just use the actual ints I guess

Simulant Over a year ago

with the final static int USERNAME = 1; declaration your accresscodes get a readable name.

amicngh · Accepted Answer · 2012-07-13 14:31:40Z

0

Wrong way.You need to call the enum using DBfields.PASSWORD.

answered Jul 13, 2012 at 14:31

amicngh

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Comments

zhaoyw · Accepted Answer · 2012-07-13 14:35:29Z

0

You need to call like this: DBfields.PASSWORD

answered Jul 13, 2012 at 14:35

zhaoyw

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