But you can leave it up to the caller to open the connection - meaning
you just don't open or close any connections.
public int getUserCount() {
return queryScalar(Integer.class, "select count(*) from people");
}
And then have the calling code open and close the connection:
openConnection();
try {
...
getUserCount();
...
} finally {
closeConnection();
}
(The idea is that there is a stack of connections and when you do
something you always use the connection at the top of the stack.)
On Feb 22, 7:24 pm, Robert Fischer <[email protected]>
wrote:
> The problem is this code:
>
> public int getUserCount() {
> openConnection();
> try {
> return queryScalar(Integer.class, "select count(*) from
> people");
> } finally {
> closeConnection();
> }
>
> }
>
> That's 1 semantically meaningful line surrounded by 5 lines of boilerplate
> plumbing. Which means
> that it's really 1/6th actual code, and 5/6th noise. That's a pretty poor
> signal to noise ratio.
>
> It's even worse when you're dealing with raw JDBC calls, since you have to
> think about preparing
> statements and managing connections and data sets and the like.
>
> ~~ Robert.
>
>
>
> Christian Hvid wrote:
> > I don't understand - why would that be a problem? (That you have
> > explictly open and close your database connection).
>
> > On Feb 22, 7:09 pm, Robert Fischer <[email protected]>
> > wrote:
> >> +1 for Spring JDBC: it manages all that openConnection/closeConnection
> >> noise for you, which means
> >> that your JDBC code can *also* start to be expressive.
>
> >> ~~ Robert.
>
> >> Rakesh wrote:
> >>> have you looked at Spring JDBC? It has a similar interface and manages
> >>> the connections for you.
> >>> I think if you go down a non-orm route and want to have lots of sql,
> >>> Ibatis is quite common - not used it so can't say for sure.
> >>> Spring JDBC though is very nice and have used it extensively.
> >>> Rakesh
> >>> On Sun, Feb 22, 2009 at 2:21 PM, Christian Hvid
> >>> <[email protected]> wrote:
> >>>> Hi Java people.
> >>>> I have been toying with simplier ways of doing embedded SQL in Java.
> >>>> And would like your comments on this one?
> >>>>http://code.google.com/p/chalkmine/
> >>>> It allows you to write code like this:
> >>>> openConnection();
> >>>> try {
> >>>> int count = queryScalar(Integer.class, "select count(*) from
> >>>> people");
> >>>> System.out.println("There are "+count+" people in the bin.");
> >>>> } finally {
> >>>> closeConnection();
> >>>> }
> >>>> or
> >>>> openConnection();
> >>>> try {
> >>>> List<Person> people = queryList(Person.class, "select name,
> >>>> time_in_the_bin from people");
> >>>> for (Person p : people)
> >>>> System.out.println(p.getName()+" has been "+p.getTimeInTheBin()
> >>>> +" hours in the bin.");
> >>>> } finally {
> >>>> closeConnection();
> >>>> }
> >>>> (Provided that Person has a constructor matching the types of name,
> >>>> time_in_the_bin. Probably Person(String, int).)
> >>>> Where the methods openConnection, queryScalar, queryList,
> >>>> closeConnection are statically imported.
> >>>> openConnection() figures out the name of the calling class, looks up a
> >>>> configuration, opens a connection and puts in a ThreadLocal container.
> >>>> queryScalar(Class, String, ...) performs a query with a single row
> >>>> result that is "cast" to the given class.
> >>>> queryList(Class, String, ...) performs a query and returns the result
> >>>> as a list of the given class.
> >>>> I would like to turn it into a full-fledged open source project.
> >>>> But since it is incredibly hard for a new open source project to gain
> >>>> traction I would like to figure out whether it is interesting enough
> >>>> first.
> >>>> -- Christian
> >> --
> >> ~~ Robert Fischer.
> >> Grails Training http://GroovyMag.com/training
> >> Smokejumper Consultinghttp://SmokejumperIT.com
> >> Enfranchised Mind Bloghttp://EnfranchisedMind.com/blog
>
> >> Check out my book, "Grails Persistence with GORM and
> >> GSQL"!http://www.smokejumperit.com/redirect.html
>
> --
> ~~ Robert Fischer.
> Grails Training http://GroovyMag.com/training
> Smokejumper Consultinghttp://SmokejumperIT.com
> Enfranchised Mind Bloghttp://EnfranchisedMind.com/blog
>
> Check out my book, "Grails Persistence with GORM and
> GSQL"!http://www.smokejumperit.com/redirect.html
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