How to annotate an Object to String Map in Hibernate

Question

I have two objects: Entity and Secondary. The Entity contains a Map of Secondary to String. It also has a composite key.

I had the mapping working with JDO, but now it is(past) time to move to JPA.

I can't figure out how to write the annotations to make it work,

There are three tables in the DB containing data.

desc map_table
Name       Null     Type         
---------- -------- ------------ 
ENTITYID     NOT NULL VARCHAR2(12) 
ENTITYSOURCE NOT NULL NUMBER(1)    
SECONDARYID  NOT NULL VARCHAR2(20) 
VALUE        NOT NULL VARCHAR2(16) 

desc entity
Name       Null     Type         
---------- -------- ------------ 
ID     NOT NULL VARCHAR2(12) 
SOURCE NOT NULL NUMBER(1)    
.....

desc secondary
Name       Null     Type         
---------- -------- ------------ 
ID     NOT NULL VARCHAR2(12) 
name            NUMBER(1)    

I am running Hibernate 4.2.19

The main class:

@Entity
@Table(name="ENTITY")
public class Entity
{
    @EmbeddedId
    private EntityKey key;

    @SomehtingIHavntFiguredOut
    private Map<Secondary, String> domainConfig = new HashMap<Secondary, String>(); 
}

Here is the JDO mapping that I am leaving behind:

<field name="map" table="MAP_TABLE" default-fetch-group="true">
<map key-type="com.foo.Secondary" value-type="String" />
<join>
    <column name="ENTIYID" target="ID"/>
    <column name="ENTITYSOURCE" target="SOURCE"/>
</join>
<key>
    <column name="SECONDARYID"/>
</key>
<value>
    <column name="VALUE"/>
</value>

Answer 1

My solution

@ElementCollection
@CollectionTable(name="MAP_TABLE", joinColumns={
        @JoinColumn(name="entityid",referencedColumnName="id"),
        @JoinColumn(name="entitysource",referencedColumnName="source")
     })
@MapKeyJoinColumn(name="secondaryid")
@Column(name = "VALUE")
private Map<Secondary, String> domainConfig = new HashMap<Secondary, String>(); 

I was unclear on when to use @ElementCollection, and when to use @OneToMany. I think because the values are primitives The correct annotation is @ElementCollection.