Problem:
1)Given an entity Teacher where a Teacher can teach many Subjects.
2)Teacher(name,Subject) is a Composite Key.
3)A Subject can have 1 or more ParentSubject.
Solution:
1)I used the following threads Thread1 Thread2 Thread3,Thread4 to find the solution to the problem and implemented the above solution but could not write proper implementation.
2)For a Composite key I used subjectId and teacherId because I was unable to map Subject with composite key
Q)Can anyone guide me how to find solution to the above problem.
Below is the following Code:
public class OurLogic {
public static void main(String args[])
{
Configuration cfg = new Configuration();
cfg.configure("hibernate.cfg.xml");
SessionFactory factory = cfg.buildSessionFactory();
Session session = factory.openSession();
//parent object
Teacher t =new Teacher();
t.setTeacherId(101);
t.setTeacherName("Jalaj");
//creating 3 child objects
Subject s1=new Subject();
s1.setSubjectId(504);
s1.setSubjectName("JSE");
Subject s2=new Subject();
s2.setSubjectId(505);
s2.setSubjectName("JEE");
Subject s3=new Subject();
s3.setSubjectId(506);
s3.setSubjectName("Spring");
// adding child objects to set, as we taken 3rd property set in parent
Set s=new HashSet();
s.add(s1);
s.add(s2);
s.add(s3);
t.setSubjects(s);
Transaction tx = session.beginTransaction();
session.save(t);
tx.commit();
session.close();
System.out.println("One To Many is Done..!!");
factory.close();
}
}
public class Subject implements Serializable{
private int subjectId;
private String subjectName;
private int forevenId;
public int getSubjectId() {
return subjectId;
}
public void setSubjectId(int subjectId) {
this.subjectId = subjectId;
}
public String getSubjectName() {
return subjectName;
}
public void setSubjectName(String subjectName) {
this.subjectName = subjectName;
}
public int getForevenId() {
return forevenId;
}
public void setForevenId(int forevenId) {
this.forevenId = forevenId;
}
}
public class Teacher implements Serializable{
private int teacherId;
private String teacherName;
private Set subjects;
public int getTeacherId() {
return teacherId;
}
public void setTeacherId(int teacherId) {
this.teacherId = teacherId;
}
public String getTeacherName() {
return teacherName;
}
public void setTeacherName(String teacherName) {
this.teacherName = teacherName;
}
public Set getSubjects() {
return subjects;
}
public void setSubjects(Set subjects) {
this.subjects = subjects;
}
}
public class TeachSubject implements Serializable{
private Long subjectId;
private Long teacherId;
// an easy initializing constructor
public TeachSubject(Long testId, Long customerId){
this.subjectId = subjectId;
this.teacherId = teacherId;
}
public Long getSubjectId() {
return subjectId;
}
public void setSubjectId(Long subjectId) {
this.subjectId = subjectId;
}
public Long getTeacherId() {
return teacherId;
}
public void setTeacherId(Long teacherId) {
this.teacherId = teacherId;
}
@Override
public boolean equals(Object arg0) {
if(arg0 == null) return false;
if(!(arg0 instanceof TeachSubject)) return false;
TeachSubject arg1 = (TeachSubject) arg0;
return (this.subjectId.longValue() == arg1.getSubjectId().longValue()) && (this.teacherId.longValue() == arg1.getTeacherId().longValue());
}
@Override
public int hashCode() {
int hsCode;
hsCode = subjectId.hashCode();
hsCode = 19 * hsCode+ teacherId.hashCode();
return hsCode;
}
}
ERROR:
Exception in thread "main" org.hibernate.boot.InvalidMappingException: Could not parse mapping document: TeachSubject.hbm.xml (RESOURCE)
at org.hibernate.boot.jaxb.internal.InputStreamXmlSource.doBind(InputStreamXml Source.java:46)
at org.hibernate.boot.jaxb.internal.UrlXmlSource.doBind(UrlXmlSource.java:36)
at org.hibernate.boot.spi.XmlMappingBinderAccess.bind(XmlMappingBinderAccess.java:59)
at org.hibernate.boot.MetadataSources.addResource(MetadataSources.java:274)
at org.hibernate.boot.cfgxml.spi.MappingReference.apply(MappingReference.java:70)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:413)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:723)
at str.OurLogic.main(OurLogic.java:19)
Caused by: org.hibernate.boot.MappingException: Error accessing stax stream : origin(TeachSubject.hbm.xml)
at org.hibernate.boot.jaxb.internal.AbstractBinder.seekRootElementStartEvent(AbstractBinder.java:141)
at org.hibernate.boot.jaxb.internal.AbstractBinder.doBind(AbstractBinder.java:101)
at org.hibernate.boot.jaxb.internal.AbstractBinder.bind(AbstractBinder.java:57)
at org.hibernate.boot.jaxb.internal.InputStreamXmlSource.doBind(InputStreamXmlSource.java:43)
... 9 more
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[5,2]
Message: The markup in the document preceding the root element must be well-formed.
at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:601)
at com.sun.xml.internal.stream.XMLEventReaderImpl.peek(XMLEventReaderImpl.java:276)
at javax.xml.stream.util.EventReaderDelegate.peek(EventReaderDelegate.java:104)
at org.hibernate.boot.jaxb.internal.stax.BufferedXMLEventReader.peek(BufferedXMLEventReader.java:96)
at org.hibernate.boot.jaxb.internal.AbstractBinder.seekRootElementStartEvent(AbstractBinder.java:137)
... 12 more
