On Fri, 12 Jul 2002, Struts Newsgroup wrote:
> Date: Fri, 12 Jul 2002 18:40:02 -0700
> From: Struts Newsgroup <[EMAIL PROTECTED]>
> Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Subject: Re: DynaBeans, DynaClass, DynaMen
>
> Subject: Re: DynaBeans, DynaClass, DynaMen
> From: "Vic C." <[EMAIL PROTECTED]>
> ===
> Looks a bit like
> http://www.javaworld.com/javaworld/jw-02-2001/jw-0202-cachedrow.html
> listing #3 of disconnected row set.
>
> Can we get metaData out of it so I can write "auto" updates?
> So a DAO that has a Iterator of DynaBeans.
All DynaBean implementations support metadata. From a particular DynaBean
instance you can say something like:
DynaProperty descriptors[] = dynaBean.getDynaClass().getDynaProperties();
and iterate through the descriptors to see what is there, very similar to
what you can do with standard JavaBeans by calling:
PropertyDescriptor descriptors[] =
PropertyUtils.getPropertyDescriptors(javabean);
> Where is DynaBean? Commons?
Yep. It's part of the commons-beanutils package. Most recent nightly
builds (which are also packaged with nightly builds of Struts) are at:
http://jakarta.apache.org/builds/jakarta-commons/nightly/commons-beanutils/
The new feature discussed below will be in tomorrow's (20020713) build.
> Vic
>
Craig
> Craig R. McClanahan wrote:
> > I implemented something a little more memory-efficient than this (doesn't
> > require the entire result set to be in memory) in tonight's nightly build
> > of commons-beanutils, which will therefore be available in the 20020713
> > nightly build of Struts. You use it something like this:
> >
> > Connection conn = ...;
> > Statement stmt = conn.createStatement();
> > ResultSet rs = stmt.executeQuery("select * from customers");
> > Iterator rows = (new ResultSetDynaClass(rs)).iterator();
> > while (rows.hasNext()) {
> > DynaBean row = (DynaBean) rows.next();
> > System.out.println("Processing customer " + row.get("account_id"));
> > ... access this row as a DynaBean ...
> > }
> > rs.close();
> > stmt.close();
> >
> > I elected to avoid doing the type conversions, so the properties you get
> > back will correspond to their types in the database.
> >
> > Craig
> >
> >
> > On Fri, 12 Jul 2002 [EMAIL PROTECTED] wrote:
> >
> >
> >>Date: Fri, 12 Jul 2002 13:56:38 -0400
> >>From: [EMAIL PROTECTED]
> >>Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]>
> >>To: [EMAIL PROTECTED]
> >>Subject: RE: DynaBeans, DynaClass, DynaMen
> >>
> >>
> >>
> >>Here is what I am using... Very simple and only returns strings...
> >>
> >>
> >> /**
> >> * Converts a resultset into an ArrayList of DynaBeans
> >> *
> >> * @param resultSet SQL result set to be converted
> >> * @return ArrayList of DynaBeans with all columnnames converted to
> >> * lowercase
> >> * @throws SQLException DOCUMENT ME!
> >> */
> >> private static ArrayList getDynaBeanArrayList(ResultSet resultSet)
> >> throws SQLException {
> >>
> >> ResultSetMetaData metaData = resultSet.getMetaData();
> >> int cols = metaData.getColumnCount();
> >> ArrayList list = new ArrayList();
> >> DynaProperty[] props = new DynaProperty[cols];
> >> BasicDynaClass dClass = null;
> >>
> >> for (int i = 1; i <= cols; i++) {
> >> props[i - 1] = new
> >>DynaProperty(metaData.getColumnName(i).toLowerCase());
> >> }
> >>
> >> try {
> >> dClass = new BasicDynaClass("test",
> >> Class.forName(
> >>
> >>"org.apache.commons.beanutils.BasicDynaBean"),
> >> props);
> >> } catch (Exception e) {
> >> e.printStackTrace();
> >> }
> >>
> >> while (resultSet.next()) {
> >>
> >> HashMap map = new HashMap(cols, 1);
> >>
> >> for (int i = 1; i <= cols; i++) {
> >> map.put(metaData.getColumnName(i).toLowerCase(),
> >> resultSet.getString(i));
> >> }
> >>
> >> try {
> >>
> >> DynaBean dbean = dClass.newInstance();
> >> BeanUtils.populate(dbean, map);
> >> list.add(dbean);
> >> } catch (Exception e) {
> >> e.printStackTrace();
> >> throw new SQLException("RequestUtils.getArrayList: "
> >> + e.toString());
> >> }
> >> } // End While
> >>
> >> return (list);
> >> }
> >>
> >>
> >>-----Original Message-----
> >>From: craigmcc [mailto:[EMAIL PROTECTED]]
> >>Sent: Friday, July 12, 2002 12:07 PM
> >>To: struts-user
> >>Subject: Re: DynaBeans, DynaClass, DynaMen
> >>
> >>
> >>
> >>
> >>On Fri, 12 Jul 2002, Thorbjoern Ravn Andersen wrote:
> >>
> >>
> >>>Date: Fri, 12 Jul 2002 07:02:57 +0200
> >>>From: Thorbjoern Ravn Andersen <[EMAIL PROTECTED]>
> >>>Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]>
> >>>To: Struts Users Mailing List <[EMAIL PROTECTED]>
> >>>Subject: Re: DynaBeans, DynaClass, DynaMen
> >>>
> >>>[EMAIL PROTECTED] skrev:
> >>>
> >>>
> >>>>...anyone remember DynaMen?
> >>>>
> >>>>Anyhow... I got a Dynabean mechanism working that builds a DynaBean
> >>>>based on the metadata of a SQL result set, populates and array of the
> >>>>little buggers and passes it back to me. For displaying I have a tag
> >>>>library that does not like a call to get('name') as the field name.
> >>>>What is the best way to get around this?
> >>>>
> >>>
> >>>I wrote an AnonyBeans package which uses BCEL to generate beans on the
> >>>fly based on a ResultSet. It is alpha code but works for me, and is
> >>>usable anywhere where you need a real traditional bean, but where you
> >>
> >>do
> >>
> >>>not want to serialize it or use its type in Java source.
> >>>
> >>>Is this interesting?
> >>>
> >>
> >>I think it would be interestesting, even though it might not be
> >>universally useful (some containers won't let you introduce new classes
> >>at
> >>runtime).
> >>
> >>I'd also be interested in a mechanism that converted a ResultSet into a
> >>custom DynaClass, with a corresponding DynaBean for each row. This
> >>would
> >>be trivially simple to do -- so simple that it probably makes a
> >>worthwhile
> >>addition to commons-beanutils itself if someone wanted to take this on.
> >>
> >>This wouldn't help you create dynamic input forms, but it would make a
> >>completely flexible bean-like wrapper around a result set so you can use
> >>Struts tags to display stuff.
> >>
> >>
> >>>--
> >>> Thorbjørn Ravn Andersen http://biobase.dk/~tra
> >>
> >>Craig
> >>
> >>
> >>--
> >>To unsubscribe, e-mail:
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> >><mailto:[EMAIL PROTECTED]>
> >>
> >>
> >>
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> >>
> >>
> >
> >
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>
>
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