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From Rainer Döbele <doeb...@esteam.de>
Subject re: svn commit: r791597 - /incubator/empire-db/trunk/empire-db/src/main/java/org/apache/empire/db/DBReader.java
Date Tue, 07 Jul 2009 08:01:37 GMT
Hi Francis,

thanks for your comment and of course you are right.
The javadoc should be adjusted and I actually haven't rethought the reuse of maxItems since
it was already in there - and I don't really want to touch this now.

Rainer

Francis De Brabandere wrote:
> Re: svn commit: r791597 - /incubator/empire-db/trunk/empire-
> db/src/main/java/org/apache/empire/db/DBReader.java
> 
> public final <T> ArrayList<T> getBeanList(Class<T> t, int maxItems)
> 
> The javadoc for this method does not indicate negative maxItems values
> as no limit. And I think it would be better to say any negative value
> instead of -1 since using other negative values is not documented at
> the moment...
> (for the generic method as well of course)
> 
> One more thing:
> I believe it is bad practice to reuse parameters in your methods. It
> is not expected that maxCount actually changes during execution. In my
> eyes this is a micro-optimization that hinders readability.
> So far my bitching :-)
> 
> On Mon, Jul 6, 2009 at 10:03 PM, <doebele@apache.org> wrote:
> > Author: doebele
> > Date: Mon Jul  6 20:03:21 2009
> > New Revision: 791597
> >
> > URL: http://svn.apache.org/viewvc?rev=791597&view=rev
> > Log:
> > EMPIREDB-42
> >
> > Modified:
> >    incubator/empire-db/trunk/empire-
> db/src/main/java/org/apache/empire/db/DBReader.java
> >
> > Modified: incubator/empire-db/trunk/empire-
> db/src/main/java/org/apache/empire/db/DBReader.java
> > URL: http://svn.apache.org/viewvc/incubator/empire-db/trunk/empire-
> db/src/main/java/org/apache/empire/db/DBReader.java?rev=791597&r1=79159
> 6&r2=791597&view=diff
> >
> =======================================================================
> =======
> > --- incubator/empire-db/trunk/empire-
> db/src/main/java/org/apache/empire/db/DBReader.java (original)
> > +++ incubator/empire-db/trunk/empire-
> db/src/main/java/org/apache/empire/db/DBReader.java Mon Jul  6 20:03:21
> 2009
> > @@ -24,6 +24,7 @@
> >  import java.sql.ResultSet;
> >  import java.sql.SQLException;
> >  import java.util.ArrayList;
> > +import java.util.Collection;
> >  import java.util.HashMap;
> >  import java.util.Iterator;
> >  import java.util.Map;
> > @@ -623,17 +624,17 @@
> >     }
> >
> >     /**
> > -     * Returns the result of a query as a list of objects resticted
> > +     * Returns the result of a query as a list of objects restricted
> >      * to a maximum number of objects (unless maxCount is -1).
> >      *
> > -     * @param c the class type of the objects in the list
> > +     * @param c the collection to add the objects to
> > +     * @param t the class type of the objects in the list
> >      * @param maxCount the maximum number of objects
> > -     * @param <T> the type of the objects in the list
> >      *
> >      * @return the list of <T>
> >      */
> >     @SuppressWarnings("unchecked")
> > -    public <T> ArrayList<T> getBeanList(Class<T> c, int maxCount)
> > +    public <C extends Collection<T>, T> C getBeanList(C c, Class<T>
> t, int maxCount)
> >     {
> >         // Check Recordset
> >         if (rset == null)
> > @@ -649,11 +650,10 @@
> >             for (int i = 0; i < colList.length; i++)
> >                 paramTypes[i] =
> DBExpr.getValueClass(colList[i].getDataType());
> >             // Find Constructor
> > -            Constructor ctor = findMatchingAccessibleConstructor(c,
> paramTypes);
> > +            Constructor ctor = findMatchingAccessibleConstructor(t,
> paramTypes);
> >             Object[] args = (ctor!=null) ? new
> Object[getFieldCount()] : null;
> >
> >             // Create a list of beans
> > -            ArrayList<T> list = new ArrayList<T>();
> >             while (moveNext() && maxCount != 0)
> >             { // Create bean an init
> >                 if (ctor!=null)
> > @@ -661,21 +661,21 @@
> >                     for (int i = 0; i < getFieldCount(); i++)
> >                         args[i] = getValue(i);
> >                     T bean = (T)ctor.newInstance(args);
> > -                    list.add(bean);
> > +                    c.add(bean);
> >                 }
> >                 else
> >                 {   // Use Property Setters
> > -                    T bean = c.newInstance();
> > +                    T bean = t.newInstance();
> >                     if (getBeanProperties(bean)==false)
> >                         return null;
> > -                    list.add(bean);
> > +                    c.add(bean);
> >                 }
> >                 // Decrease count
> >                 if (maxCount > 0)
> >                     maxCount--;
> >             }
> >             // done
> > -            return list;
> > +            return c;
> >         } catch (InvocationTargetException e)
> >         {
> >             error(e);
> > @@ -690,20 +690,30 @@
> >             return null;
> >         }
> >     }
> > -
> > +
> >     /**
> >      * Returns the result of a query as a list of objects.
> >      *
> > -     * @param c the class type of the objects in the list
> > -     * @param <T> the type of the objects in the list
> > +     * @param t the class type of the objects in the list
> > +     * @param maxCount the maximum number of objects
> >      *
> >      * @return the list of <T>
> >      */
> > -    public <T> ArrayList<T> getBeanList(Class<T> c)
> > -    {
> > -        return getBeanList(c, -1);
> > +    public final <T> ArrayList<T> getBeanList(Class<T> t, int
> maxItems) {
> > +        return getBeanList(new ArrayList<T>(), t, maxItems);
> >     }
> > -
> > +
> > +    /**
> > +     * Returns the result of a query as a list of objects.
> > +     *
> > +     * @param t the class type of the objects in the list
> > +     *
> > +     * @return the list of <T>
> > +     */
> > +    public final <T> ArrayList<T> getBeanList(Class<T> t) {
> > +        return getBeanList(t, -1);
> > +    }
> > +
> >     /**
> >      * Moves the cursor down one row from its current position.
> >      *
> >
> >
> >
> 
> 
> 
> --
> http://www.somatik.be
> Microsoft gives you windows, Linux gives you the whole house.

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