iBatis Error with Recursive Generics

From: "andrew cooke" <andrew@...>

Date: Wed, 3 Sep 2008 13:10:01 -0400 (CLT)

I have a base class for ORM that looks something like this:

public class Keyed<KeyType extends Comparable<KeyType>>
implements Comparable<Keyed<KeyType>>
{
  private KeyType key;
  protected final void setKey(final KeyType key) {...}
  ...
}

For some reason, iBatis does not like this, even thought it was fine (as
far as I can tell) with an earlier version that was also generic (but did
not include the recursive Comparable declaration).

The error when you try to map (sublasses of) this is given below (in full
for Google).

I tried tracking what was causing this, and it seems that the type handler
is not inferred correctly while reading the configuration.  Rather than
digging further I found a simple workaround - specify the type handler by
hand.

So my maps now look like:

<sqlMap namespace="entity">
  <resultMap id="entity-result" class="...Entity">
    <result property="key" column="entity_id"
     typeHandler="com.ibatis.sqlmap.engine.type.StringTypeHandler"/>
    <result property="title" column="title"/>
    <result property="description" column="description"/>
    ...
  </resultMap>
  ...
</sqlMap>

Note the explicit typeHandler.

Andrew


03-Sep-2008 13:06:32 com.isti.kpidb.KpiDb getEntities
SEVERE: Failed to read Entities
com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred in maps/entity.xml.
--- The error occurred while applying a result map.
--- Check the entity.entity-result.
--- Check the result mapping for the 'key' property.
--- Cause: com.ibatis.sqlmap.client.SqlMapException: No type handler could
be found to map the property 'key' to the column 'entity_id'.  One or both
of the types, or the combination of types is not supported.
	at
com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryWithCallback(MappedStatement.java:204)
	at
com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryForList(MappedStatement.java:139)
	at
com.ibatis.sqlmap.engine.mapping.statement.CachingStatement.executeQueryForList(CachingStatement.java:97)
	at
com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:567)
	at
com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:541)
	at
com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForList(SqlMapSessionImpl.java:118)
	at
com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.queryForList(SqlMapClientImpl.java:94)
	at com.isti.kpidb.KpiDb.queryForList(KpiDb.java:331)
	at com.isti.kpidb.KpiDb.queryForList(KpiDb.java:311)
	at com.isti.kpidb.KpiDb.getEntities(KpiDb.java:102)
	at com.isti.kpidb.demo.ListEntities.execute(ListEntities.java:23)
	at com.isti.kpidb.demo.Demo.processInput(Demo.java:125)
	at com.isti.kpidb.demo.Demo.mainLoop(Demo.java:84)
	at com.isti.kpidb.demo.Demo.<init>(Demo.java:58)
	at com.isti.kpidb.demo.Demo.main(Demo.java:183)
Caused by: com.ibatis.sqlmap.client.SqlMapException: No type handler could
be found to map the property 'key' to the column 'entity_id'.  One or both
of the types, or the combination of types is not supported.
	at
com.ibatis.sqlmap.engine.mapping.result.ResultMap.getPrimitiveResultMappingValue(ResultMap.java:613)
	at
com.ibatis.sqlmap.engine.mapping.result.ResultMap.getResults(ResultMap.java:345)
	at
com.ibatis.sqlmap.engine.execution.SqlExecutor.handleResults(SqlExecutor.java:384)
	at
com.ibatis.sqlmap.engine.execution.SqlExecutor.handleMultipleResults(SqlExecutor.java:300)
	at
com.ibatis.sqlmap.engine.execution.SqlExecutor.executeQuery(SqlExecutor.java:189)
	at
com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.sqlExecuteQuery(MappedStatement.java:221)
	at
com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryWithCallback(MappedStatement.java:189)
	... 14 more