java - 扩展和抽象问题

Question

我创建了一个名为GeneraFriendsTable 代码的通用类，如下所示：

public abstract class GeneralFriendsTable {
    public static String TABLE_NAME;
    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_NAME = "name";

    public static void onCreate(SQLiteDatabase db) {
        String DATABASE_CREATE = "CREATE TABLE " + TABLE_NAME + "(" +
            COLUMN_ID        + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
            COLUMN_UNAME     + " TEXT, " + ");";
            db.execSQL(DATABASE_CREATE);
    }

    public static void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
    }
}

我想从此类扩展时强制初始化字段TABLE_NAME。

例如：

public class NewFriendsTable extends GeneralFriendsTable {
    public static final String TABLE_NAME = "leaved_friends";
}

主要问题是：onCreate()使用TABLE_NAME扩展类 可以正常工作吗？

Answer 1

在超类中创建一个抽象函数来获取表名：

public abstract class GeneralFriendsTable {

    public abstract String getTableName();

    public static void onCreate(SQLiteDatabase db) {
        String DATABASE_CREATE = "CREATE TABLE " + getTableName() + ...
    }
}

然后在具体的子类中实现函数：

public class NewFriendsTable extends GeneralFriendsTable {
    public String getTableName() {
        return "leaved_friends";
    }
}