If I get you right you could use a resultMap that itself uses other
resultMap instances to populate its subclass attributes.
Lets say, you have got a select like "SELECT * FROM mytable" that
returns a resultSet of 103 columns, several of which get mapped to the
top-level class with a resultMap like so:
<resultMap class="package.TopClass" id="TopResult">
<result column="id" property="id"/>
<result column="property1" property="property1"/>
<result column="property2" property="property2"/>
...
<result column="propertyN" property="propertyN"/>
</resultMap>
Now you create a resultMap for every subset class like so:
<resultMap class="package.SubClass1" id="SubResult1">
<result column="subProperty1" property="subProperty1"/>
<result column="subProperty2" property="subProperty2"/>
...
</resultMap>
<resultMap class="package.SubClass2" id="SubResult2">
<result column="subProperty3" property="subProperty3"/>
<result column="subProperty4" property="subProperty4"/>
...
</resultMap>
Now you can create a "composite" resultMap that uses all those
resultMaps to create a TopClass instance filled with each of its
properties and its SubClass properties:
<resultMap class="package.TopClass" extends="TopResult"
id="CompositeTopResult">
<result property="subClassProperty1" resultMap="SubResult1"/>
<result property="subClassProperty2" resultMap="SubResult2"/>
</resultMap>
Your select now can use this resultMap to populate a complete TopClass
instance with both its flat fields and its subclass instances.
Hope that helps :)
Best regards -
Ole.
Amin Ahmad wrote:
> Hello,
>
> I am working with a 103-column table that tracks a variety of
> information for a provider. Rather than modeling this as a single class
> with 103 attributes, I have defined a top-level class that contains a
> few core provider attributes, and "subject-area" classes that group
> disjoint subsets of attributes by domain ( e.g. Financial, Metrics,
> Demographics). The top level bean contains an attribute for each of
> these "subject-area" classes.
>
> My problem lies in effectively using iBatis to populate this structure
> from a table row. My current approach is to use a custom type handler to
> populate the subject area bean. The example below shows how I am
> populating the "metrics" attribute in the resultMap of the top-level
> provider class.
>
> <result property="metrics"
> column="QT_ETHR_AVLB_RSTR"
>
> typeHandler="com.cgi.wasacwis.typehandlers.ProviderMetricsTypeHandler"/>
>
> The metrics attribute is actually a "subject-area" class that holds ~20
> attributes from the row. The custom type handler,
> ProviderMetricsTypeHandler , contains code for creating and populating
> the fields. To illustrate, I have included the method "getResult" below:
>
> private ProviderMetrics getResult(ResultSet r) throws SQLException {
> ProviderMetrics result =
> WasacwisFactory.eINSTANCE.createProviderMetrics();
>
> result.setEitherAvailableRestricted
> (r.getLong("QT_ETHR_AVLB_RSTR"));
> result.setEitherProviderRestricted
> (r.getLong("QT_ETHR_PRVD_RSTR"));
> result.setFemaleAvailableRestricted
> (r.getLong("QT_FEML_AVLB_RSTR"));
> result.setFemaleProviderRestricted
> (r.getLong("QT_FEML_PRVD_RSTR"));
> result.setMaleAvailableRestricted
> (r.getLong("QT_MALE_AVLB_RSTR"));
> result.setMaleProviderRestricted
> (r.getLong("QT_MALE_PRVD_RSTR"));
> result.setProviderParticipantsUnder18
> (r.getLong("QT_PRVD_PART_UND18"));
> result.setProviderParticipantsUnder2
> (r.getLong("QT_PRVD_PART_UNDR2"));
> result.setTotalAvailableBedCapacity
> (r.getLong("QT_TOT_AVLB_BEDCAP"));
> result.setTotalAvailableRestricted
> (r.getLong("QT_TOT_AVLB_RSTR"));
> result.setTotalAvailableUnder18
> (r.getLong("QT_TOT_AVLB_UNDR18"));
> result.setTotalAvailableUnder2
> (r.getLong("QT_TOT_AVLB_UNDR2"));
> result.setTotalEitherPlaced
> (r.getLong("QT_TOT_ETHR_PLCD"));
> result.setTotalEitherReserved
> (r.getLong("QT_TOT_ETHR_RSVD"));
> result.setTotalFemalePlaced
> (r.getLong("QT_TOT_FEML_PLCD"));
> result.setTotalFemaleReserved
> (r.getLong("QT_TOT_FEML_RSVD"));
> result.setTotalMalePlaced
> (r.getLong("QT_TOT_MALE_PLCD"));
> result.setTotalMaleReserved
> (r.getLong("QT_TOT_MALE_RSVD"));
> result.setTotalPlaced
> (r.getLong("QT_TOT_PLCD"));
> result.setTotalPlacedUnder18
> (r.getLong("QT_TOT_PLCD_UNDR18"));
> result.setTotalPlacedUnder2
> (r.getLong("QT_TOT_PLCD_UNDR2"));
> result.setTotalProviderBedCapacity
> (r.getLong("QT_TOT_PRVD_BEDCAP"));
> result.setTotalProviderRestricted
> (r.getLong("QT_TOT_PRVD_RSTR"));
> result.setTotalReserved
> (r.getLong("QT_TOT_RSVD"));
> result.setTotalReservedUnder18
> (r.getLong("QT_TOT_RSVD_UNDR18"));
> result.setTotalReservedUnder2
> (r.getLong("QT_TOT_RSVD_UNDR2"));
>
> return result;
> }
>
> Needless to say, I am writing the entire mapping for the provider
> metrics class in Java, and this isn't making good use of iBatis. Can
> anyone suggest a better strategy?
>
> thank you,
> Amin
