[jboss-user] [JBoss Seam] - EntityQuery restriction help

[dloebbe]

Hi all,
after searching the examples, documentation and forum for a solution I can't get the following use case to work:
I like to restrict the EntityQuery for object A by a related Object B. The Entities and search-dialogue are created by seam-gen. But I like to add a simple single select list of object of class b as search criteria.

My code:

  | @Entity
  | public class A implements Serializable
  | {
  | 	@Id
  | 	@GeneratedValue(strategy = GenerationType.AUTO)
  | 	private Long				id;
  | 
  | 	@ManyToOne(fetch = FetchType.EAGER)
  | 	@JoinColumn(name = "bid", nullable = true)
  | 	private B			b;
  | }
  | 
  | @Entity
  | public class B implements Serializable
  | {
  | 	@Id
  | 	@GeneratedValue(strategy = GenerationType.AUTO)
  | 	private Long				id;
  | 
  | 	@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "b")
  | 	private Set<A> as;
  | }
  | 

I like to create an EntityQuery, which searches / returns Objects of class A related to a specific Object of class B. One of my tries looks as follows:

  | @Name("aList")
  | public class AList extends EntityQuery
  | {
  | 	private static final String[]	RESTRICTIONS	= {
  | 	        "b = #{aList.a.b}", };
  | 
  | 	@Override
  | 	public String getEjbql()
  | 	{
  | 		return "select a from A as a join a.b as b";
  | 	}
  | }
  | 
Which produces an error like:

  | Caused by: java.lang.IllegalArgumentException: argument type mismatch
  | 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  | 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  | 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  | 	at java.lang.reflect.Method.invoke(Method.java:597)
  | 	at javax.el.BeanELResolver.setValue(BeanELResolver.java:108)
  | 	... 58 more
  | 


Another one like this:

  | @Name("aList")
  | public class AList extends EntityQuery
  | {
  | 	private static final String[]	RESTRICTIONS	= {
  | 	        "a.b = #{aList.a.b}", };
  | 
  | 	@Override
  | 	public String getEjbql()
  | 	{
  | 		return "select a from A as a";
  | 	}
  | }
  | 
Resolves in the same. In both cases, the query parameter is set properly to an object of class B.


What am I doing wrong? Or can just someone provide an example on how to restrict EntityQueries by @ManyToOne-related Entities?

Thanks for help,

Daniel

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