I tried Sunburn's mod to BasicFeature and it seems to work.
I looked again at Paolo's mod and it looks like it will work.
I have tested my mod and it seems to work.
Larry
On Fri, May 1, 2009 at 10:17 AM, Paolo Rizzi <g...@oicom.com> wrote:
> > An example of the standard usage pattern for JDBC can be seen in:
> > com.vividsolutions.jump.datastore.jdbc.ValueConverterFactory.
> > Regardless of whether you use ResultSet's getObject() or something like
> > getInt(), eventually you are going to need an object representation of
> > the data in order to work with it. BasicFeature.SetAttribute requires
> > an Object. So if you did something like: new
> > Integer(rs.getInt(columnIndex)) on a null column , the JavaDoc for
> > ResultSet says you'll get a zero int wrapped in an Integer.
> Zero is not equal to NULL by any means!!!
> The assumption that a zero can be used in place of a NULL is quite bad,
> IMHO. Is exactly the kind of stuff that makes legacy formats like
> shapes, mapinfo, etc. vastly inferior in respect to RDBMSs.
>
> >
> > I appreciate all of the clever solutions, but I will remain convinced
> > that BasicFeature can detect modification without any need for explicit
> > client methods to set it, until someone shows me proof that it can not.
> If you spend a moment to look at the code I attached in my previous
> message you'll see that it works in both cases. Non mod-aware client
> will get the automatic assumption that each and every attributes has to
> be set at least once before init can be considered ended. While
> mod-aware clients can, if they want, set the init status explicitely.
>
> >
> > regards,
> > Larry
> Bye
> Paolo
>
>
> >
> >
> > On Thu, Apr 30, 2009 at 6:24 AM, Paolo Rizzi <g...@oicom.com
> > <mailto:g...@oicom.com>> wrote:
> >
> > The previous sample code I posted was foolish, I'm sorry!!!
> >
> > Find attached a better version that uses a single Object reference
> > to track both initialization and modify state.
> >
> > During initialization this Object references a byte[] where each
> > element tracks the init state of the corresponding attribute.
> >
> > Init ends when all attributes has been set at least once or when the
> > client code calls a provided method.
> >
> > After init has ended the byte[] is discarded and the Object
> > references the static instance of Boolean.FALSE (so there's no
> > memory wasted beyound the single Object reference itself).
> >
> > After at least one attributes is set, the Object references the
> > static instance Boolean.TRUE.
> >
> > Client code can decide to force init end with a non-modified state
> > or even an already-modified state, if it likes to.
> >
> > The code does not check if the new value set for an attribute is
> > equal or not to the value already present. This is because a ==
> > check would not be good because two different Integer instances both
> > containing the same value are to be considered equal.
> > So the equals() method should be used, but that is not garanteed to
> > work with all class types, so I think it may be better to skip the
> > check altogether and consider an attribute modified in any case.
> >
> > Hope this is helpful!!! :-)
> >
> > Bye
> > Paolo
> >
> >
> >
> > public class BasicFeature {
> > private Object[] attributes;
> > private Object mods;
> >
> > public void forceInitEnded(boolean modified) {
> > //force init end and specified modify state
> > mods = modified ? Boolean.TRUE : Boolean.FALSE;
> > }
> >
> > public boolean isInitEnded() {
> > if( mods instanceof Boolean ) //init ended
> > return true;
> >
> > if( mods == null ) { //if
> > still null
> > mods = new byte[attributes.length]; //create it
> > Arrays.fill((byte[])mods,(byte)0); //fill with
> > zeros
> >
> > return false; //init not even started
> > }
> >
> > for(int i=0;i<((byte[])mods).length;i++)
> > if( ((byte[])mods)[i] == 0 ) //if any attribute never
> > flagged
> > return false; //init not ended
> >
> > forceInitEnded(false); //init ended, no mods done
> >
> > return true; //init ended
> > }
> >
> > public void setAttribute(Object[] newAttributes) {
> > //call setAttribute() for each element
> > }
> >
> > public void setAttribute(int attributeIndex, Object
> > newAttribute) {
> > if( isInitEnded() ) //if init ended
> > mods = Boolean.TRUE; //feature modified
> > else
> >
> > //if init not ended
> > ((byte[])mods)[attributeIndex] = 1; //flag the
> > attributes mod
> >
> > attributes[attributeIndex] = newAttribute;
> > }
> >
> > public boolean isModified() {
> > return isInitEnded() ? ((Boolean)mods).booleanValue() :
> false;
> > }
> > }
> >
> >
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