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From "Jeff Butler" <jeffgbut...@gmail.com>
Subject Re: Problem populating a List using groupBy
Date Fri, 23 Jun 2006 15:50:02 GMT
The first thing I see is that, with iBATIS, you cannot back a List with an
array like this.  iBATIS does not group everything together and call the set
list method one time - it will repeatedly call the get list method and add
to the list.

The get list and set list methods should be simple getters and setters to an
internal ArrayList.  So fix that first, then we'll see if anything else is
broken.

Jeff Butler


On 6/23/06, Torsten Michelmann <torsten.michelmann@gmx.de> wrote:
>
> Hi folks,
>
> again me (seems that I am touching all the rather complicated topics of
> iBatis during my very first project).
> The problem is appearing while I try to avoid an N+1 select for a 1:M
> relationship (as described on p. 36 in the latest developer guide).
> I think that I may be using the groupBy attribute in an incorrect way but
> I am not sure how it has to be done correctly. (I tried using groupBy="ID"
> as well as groupBy="id" but that returned the same error).
>
> com.ibatis.common.jdbc.exception.NestedSQLException:
> --- The error occurred in global/persistence/mom/MOM_SqlMap.xml.
> --- The error occurred while applying a result map.
> --- Check the MOM.r_getCustomerOrder.
> --- The error happened while setting a property on the result object.
> --- Cause: com.ibatis.common.beans.ProbeException: Could not set property
> 'customerOrderItemsList' for global.persistence.mom.CustomerOrderMapper.  Cause:
> java.lang.NullPointerException
> Caused by: java.lang.NullPointerException
> Caused by: com.ibatis.common.beans.ProbeException: Could not set property
> 'customerOrderItemsList' for global.persistence.mom.CustomerOrderMapper.  Cause:
> java.lang.NullPointerException
> Caused by: java.lang.NullPointerException
>        at
> com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryWithCallback
> (GeneralStatement.java:188)
>        at
> com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeQueryForObject
> (GeneralStatement.java:104)
>        at
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForObject(
> SqlMapExecutorDelegate.java:561)
>        at
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForObject(
> SqlMapExecutorDelegate.java:536)
>        at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForObject(
> SqlMapSessionImpl.java:93)
>        at com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.queryForObject(
> SqlMapClientImpl.java:70)
>
>
> //The mapping
>        <resultMap id="r_getCustomerOrder" class="CustomerOrderMapper"
> groupBy="orderItemKey.articleKey.articleId">
>                <result property="objectId" column="ID" />
>                <result property="comment" column="COMMENT" />
>                <result property="mom" column="IS_MOM" />
>                <result property="kimStatus" column="KIMSTATUS" />
>                <result property="customerOrderKey.customerId"
> column="CUSTOMER_ID" />
>                <result property="customerOrderKey.orderId"
> column="ORDERID" />
>                <result property="customerOrderKey.version"
> column="VERSION" />
>                <result property="customerOrderKey.moduleKey.moduleId"
> column="MODULE_ID" />
>                <result property="customerOrderKey.collectionKey.seasonId"
> column="SAISON" />
>                <!-- <result property="
> customerOrderKey.collectionKey.collectionCategoryId" column="SEGMENT"
> />  not existant within MOM-->
>                <result property="customerOrderKey.collectionKey.segmentId"
> column="SEGMENT" />
> <!--    <result property="customerOrderItemsList" column="{id=ID}"
> select="getCustomerOrderItem" />  -->
>                <result property="customerOrderItemsList" resultMap="
> MOM.r_getCustomerOrderItem" />
>        </resultMap>
>        <resultMap id="r_getOrderItemBase" class="OrderItemBase">
>                <!-- <result property="objectId" column="" />  -->
>                <!-- <result property="salesPrice" column="" />  -->
>                <!-- <result property="recommendedRetailPrice" column=""
> />  -->
>                <!-- <result property="currency" column="" />  -->
>                <result property="orderItemKey.articleKey.articleId"
> column="ARTICLE_NUM" />
>                <result property="
> orderItemKey.articleColourKey.articleColourId" column="COLOUR" />
>
>        </resultMap>
>        <resultMap id="r_getOrderItem" class="OrderItem"
> extends="r_getOrderItemBase">
>                <result property="orderedQuantity"
> column="ORDERED_QUANTITY"/>
>        </resultMap>
>        <resultMap id="r_getCustomerOrderItem" class="CustomerOrderItem"
> extends="r_getOrderItem">
>                <result property="size" column="ARTICLE_SIZE" />
>                <result property="length" column="ARTICLE_LENGTH" />
>        </resultMap>
>
> //The query
>                        SELECT c.ID, c.COMMENT, c.KIMSTATUS, c.CUSTOMER_ID,
> c.ORDERID, c.VERSION, c.MODULE_ID, c.SAISON, c.SEGMENT, c.IS_MOM,
> a.ARTICLE_NUM, d.COLOUR, d.ORDERED_QUANTITY,e.ARTICLE_SIZE,
> e.ARTICLE_LENGTH
>                        FROM
>                                MENU.ARTICLE a inner join
> MENU.ARTICLE2MENUORDER b on a.ARTICLE_NUM=b.ARTICLE_NUM
>                    inner join MENU.MENUORDER c on b.MENUORDER_ID=c.ID
>                    left outer join MENU.COLOUR2ARTICLE d on
> d.ART2MO_ID=b.ID
>                    left outer join MENU.SIZE2ARTICLE e on d.ART2MO_ID=b.ID
>                WHERE
>                        c.ID=#objectId#
>
>
> //Customer Order is providing only methods access an Array, thus the
> Wrapper. I have provided this class in order to allow you to ensure that I
> am not missing anything in here.
> public class CustomerOrderMapper extends CustomerOrder {
>    public void setCustomerOrderItemsList(List pCustomerOrderItemList) {
>        if (pCustomerOrderItemList.size() > 0) {
>            CustomerOrderItem[] coi= (CustomerOrderItem[])
> pCustomerOrderItemList.toArray(new CustomerOrderItem[
> pCustomerOrderItemList.size()]);
>            setCustomerOrderItems(coi);
>        }
>    }
>
>    public List getCustomerOrderItemsList() {
>        if(getCustomerOrderItems()==null)
>        {
>            return new ArrayList();
>        }
>        else
>        {
>            return Arrays.asList(getCustomerOrderItems());
>        }
>    }
> }
>
>
>
>
> --
> Gruß
> Torsten Michelmann
>
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