[Springframework-developer] JDBC Insert functionality

[Ken K. <kk...@kk...>]

Since there seems to be a consensus in favor, I would like to go ahead 
and make these changes if there are no objections,  also adding 
columnName to AbstractDataFieldMaxValueIncrementer  and removing the 
RdmsMaxValueIncrementer class. As I don't have commit rights, someone 
will have to assist me or I will need to get those rights.

Ken

Ken Krebs wrote:

> On Friday, I was working on an HSQL version of the incrementer but had 
> not completed the work before leaving for an extended holiday. I was 
> intending to use it so as to provide support in the Petclinic demo for 
> both Mysql and Hsql. I was pleased to find it done when I got back 
> :=). I have built the demo using both db's now and the insert use case 
> works well on both versions.
>
> I would like to propose a bit of refactoring to the incrementers class 
> hierarchy to enhance pluggability. As it stands now, there is a lot of 
> common functionality that is redundant in the concrete classes and 
> could be pushed up to the AbstractDataFieldMaxValueIncrementer class:
>
> 1. cacheSize field and setter
> 2. prefixWithZero field and setter
> 3. dataSource field and setter
> 4. sequenceName (Oracle) or tableName (Mysql and Hsql) field and 
> setter, perhaps renamed to incrementerName
>
> NOTE: The interface for RdmsMaxValueIncrementer is inconsistent with 
> the others and out-of-date. As it is also unsafe, perhaps it should be 
> removed altogether. It should at least be brought up-to-date.
>
>
> I have provided an example to show how these changes can benefit the 
> user (developer):
>
>
> In Petclinic, I provide beans in applicationContext.xml to configure 
> the dataSource and incrementer for my DAO bean. At present, I only 
> have 1 insert use case, addVisit.
>
> NOTE: I have elected to show the use of pooled datasources in a later 
> iteration of the demo.
>
>
> For mysql:
>
>  <bean name="dataSource" 
> class="com.interface21.jdbc.datasource.DriverManagerDataSource" >
>    <property name="driverClassName">com.mysql.jdbc.Driver</property>
>    <property name="url">jdbc:mysql://localhost:3306/petclinic</property>
>    <property name="username">pc</property>
>    <property name="password">pc</property>
>  </bean>
>    <bean name="visitIncrementer" 
> class="com.interface21.jdbc.core.support.MySQLMaxValueIncrementer" >
>    <property name="dataSource" beanRef="true">dataSource</property>
>    <property name="tableName">visits_seq</property>
>    <property name="columnName">seq</property>
>  </bean>
>
>
> For hsql:
>
>  <bean name="dataSource" 
> class="com.interface21.jdbc.datasource.DriverManagerDataSource" >
>    <property name="driverClassName">org.hsqldb.jdbcDriver</property>
>    <property name="url">jdbc:hsqldb:hsql://localhost:9001</property>
>    <property name="username">sa</property>
>  </bean>
>    <bean name="visitIncrementer" 
> class="com.interface21.jdbc.core.support.HsqlMaxValueIncrementer" >
>    <property name="dataSource" beanRef="true">dataSource</property>
>    <property name="tableName">visits_seq</property>
>  </bean>
>
>
> My DAO bean:
>
>  <bean name="clinicDAO" class="petclinic.dao.ClinicJdbcDAO" >
>    <property name="dataSource" beanRef="true">dataSource</property>
>    <property name="visitIncrementer" 
> beanRef="true">visitIncrementer</property>
>  </bean>
>  
>
> As it stands, I need to configure a separate incrementer bean for each 
> new insert use case and add a field and setter for each one to the DAO 
> or alternatively embed code using the specific concrete class names in 
> the DAO which is now generic JDBC.
>
>
> What I would like to do is something like this:
>
>  <bean name="incrementer"
>        singleton="false"
>        
> class="com.interface21.jdbc.core.support.MySQLMaxValueIncrementer" > 
> <!-- or some other concrete incrementer -->
>    <property name="dataSource" beanRef="true">dataSource</property>
>  </bean>
>
>  <bean name="clinicDAO" class="petclinic.dao.ClinicJdbcDAO" >
>    <property name="dataSource" beanRef="true">dataSource</property>
>    <property name="incrementer" beanRef="true">incrementer</property>
>  </bean>
>  
> I could then use this as a prototype bean for each of the insert use 
> cases which would then instantiate a prototype object using getBean() 
> on an AbstractDataFieldMaxValueIncrementer  reference, subsequently 
> setting the incrementerName property for that object for the 
> particular use case in code. The code remains completely generic and 
> all the database configuration/selection is done in xml. A problem 
> remains with the Mysql version in that the columnName property needs 
> to be set. This could be accomplished without breaking genericity by 
> conventionally using a default columnName, such as "seq".
>
>
>
> What do you think ???
>
>
> Ken
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