MyBatis - constructorArgs annotation and embedded objects - mybatis

Question

Is it possible to map embedded object with annotation using MyBatis in one query i.e.:Foo class:
public class Foo //immutable
{
private final Integer fooId;
private final String fooAttr;
private final Bar bar;
public Foo(Integer fooId, String fooAttr, Bar bar) //constructor
}
Bar class:
public class Bar { //immutable
private final Integer barId;
private final String barAttr;
public Bar(Integer barId, String barAttr) //constructor
}
Table FooBar:
- INT foo_id
- CHAR foo_attr
- INT bar_id
- CHAR bar_attr
Query:
#ConstructorArgs({
#Arg(column="foo_id", javaType=Integer.class),
#Arg(column="foo_attr", javaType=String.class),
Bar ?
})
Select("select * from FooBar where foo_id=#{fooId}"
public Foo getFooBy(#Param("fooId") Integer fooId);
How to map Bar class as Foo constructor argument (without using subqueries) ?

Answer 1

I know, this is painful, but the following will work:
#ConstructorArgs({
#Arg(column="foo_id", javaType=Integer.class),
#Arg(column="foo_attr", javaType=String.class),
#Arg(column="bar_id", javaType=Integer.class),
#Arg(column="bar_attr", javaType=String.class)
})
The constructor should then look like this:
public Foo(Integer fooId, String fooAttr, Integer barId, String barAttr)
this.fooId = fooId;
this.fooAttr = fooAttr;
this.bar = new Bar(barId, barAttr);
}
You could even leave Bar empty, if the ID is not set:
public Foo(Integer fooId, String fooAttr, Integer barId, String barAttr)
this.fooId = fooId;
this.fooAttr = fooAttr;
if (barId != null) {
this.bar = new Bar(barId, barAttr);
}
}