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.
Where is DynaBean? Commons?
Vic
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
>>
>>
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>
>
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