Hello
This question was originally posted in StackOverflow (http://stackoverflow.com/questions/27016778/how-to-move-items-between-collections-in-hibernate-4-3-7-final) with no satisfactory answer so far.
I have two entities mapped in my application in order to model a
Team and its
Members. A
Team can have many
Members and a
Member can belong to no more than one
Team. Everything is fine about handling this concepts. The problem comes when I try to move a Member from one existing
Team to another.
The entities are presented below, in simplified form. The very last method,
transfer(), is the one that should perform the removal of a certain
Member from its Team and send it to another one.
Code:
@Entity
public class Member extends Person {
@ManyToOne
private Team team;
protected Member() {
super();
}
public Member(Team team, String name) {
super(name);
this.team = team;
}
// Trivial getters and setters...
public Team getTeam() {
return team;
}
protected void setTeam(Team team) {
this.team = team;
}
}
@Entity
public class Team {
@Id
private long id;
private String name;
@OneToMany(mappedBy="team", cascade=CascadeType.ALL)
private List<Member> members = new ArrayList<Member>();
protected Team() {
}
public Team(String name) {
this.name = name;
}
// trivial getters and setters...
public Member addMember(String name) {
Member member = new Member(this, name);
members.add(member);
return member;
}
protected void addMember(Member member) {
members.add(member);
member.setTeam(this);
}
public void removeMember(Member member) {
members.remove(member);
}
public Member memberByName(String memberName) {
for(Member member : members)
if(member.getName().equals(memberName))
return member;
return null;
}
public Collection<Members> getMembers() {
return Collections.unmodifiableCollection(members);
}
public void transfer(Member member, Team destination) {
members.remove(member);
destination.addMember(member);
}
}
I have this unit test code that is intended to validate the transfer service
Code:
Team teamA = teamRepository.teamById(idTeamA);
Team teamB = teamRepository.teamById(idTeamB);
Team teamC = teamRepository.teamById(idTeamC);
Member zaki = teamA.memberByName("Zaki");
Member denise = teamA.memberByName("Denise");
EntityTransaction t = teamRepository.transactionBegin();
teamA.transfer(zaki, teamB);
teamA.transferir(denise, teamC);
t.commit();
I have the following exception in the
commit() line
Code:
javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist: application.domain.Member
Any ideas?
UPDATE 1:
I decided to perform a little test and changed the code of the
transfer() method as follows
Code:
public void transfer(Member member, Team destination) {
member.setTeam(this);
}
The result was curious: no error, but also no update on the tables. Hibernate couldn't track the update and the transfer simply didn't happen.
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