Hi,
Reading the book writen by Anthony PATRICIO: Java Persistence and Hibernate, There is a ManyToMany association management that matches my needs, ie:
- With additional columns in the association table.
- The association between the parent table and the table of association is a composition.
The following example from the book:
Code:
// [Coach]<> ----> *[Season]* ----> [Team]
// Coach.java
@Entity
public class Coach {
@Id
@GeneratedValue
private int id;
@ManyToMany
@MapKey
private Map<Season,Team> teams = new HashMap<Season,Team>();
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Map<Season, Team> getTeams() {
return teams;
}
public void setTeams(Map<Season, Team> teams) {
this.teams = teams;
}
}
// Season.java
@Embeddable
public class Season {
private Date startDate;
private Date endDate;
public Date getStartDate() {
return startDate;
}
public void setStartDate(Date startDate) {
this.startDate = startDate;
}
public Date getEndDate() {
return endDate;
}
public void setEndDate(Date endDate) {
this.endDate = endDate;
}
}
// Team.java
@Entity
public class Team {
@Id
@GeneratedValue
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
The example of the book (from the source above or download here
http://www.editions-eyrolles.com/Livre/9782212122596/java-persistence-et-hibernate is a project with Eclipse Embedded JBoss.
This example works well in this environment.
But in the following environments:
- JBoss AS 5.0.1 and EJB3 (or mode TransactionManagementType.BEAN TransactionManagementType.CONTAINER)
- Spring for dependency injection and transaction management
When I call the function getKey () (in the transaction) of the property "private Map <Season,Team> teams":
Code:
[...]
for (Entry<Season, Team> entry : coach.getTeams().entrySet()) {
System.out.println(entry.getValue().getName());
System.out.println(entry.getKey().getStartDate());
System.out.println(entry.getKey().getEndDate());
}
[...]
I have the following error:
Code:
java.lang.ClassCastException: java.lang.Long cannot be cast to com.et.Season
If someone understands the problem ...
Thank you.
Alexandre.
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