Transactions in JSF Netbeans 7.3.1 generated code

Question

I'm new to Java EE, following the learning by doing approach. In a very simple Mysql database with Netbeans 7.3.1 having a Patient table relates to a Person table, I'm having trouble understanding Netbeans generated code. I want to create a transaction where a Person and a Patient should be created and persisted with roll back possibility. Should i create a separate controller to handle such a transaction. Kindly help with a link to some similar example code. Code generated by Netbeans is below. (Some imports and redundant code removed)

Person.java

package entity;

import java.io.Serializable;
import java.util.Collection;
import java.util.Date;
import javax.persistence.Basic;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;

@Entity
@Table(name = "person")
@XmlRootElement

public class Person implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Integer id;
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 45)
    @Column(name = "firstname")
    private String firstname;

    @Size(max = 255)
    @Column(name = "email")
    private String email;
    @Size(max = 15)
    @Column(name = "mobile")
    private String mobile;
    @Size(max = 15)
    @Column(name = "residence")
    private String residence;
    @Size(max = 15)
    @Column(name = "office")
    private String office;
    @Size(max = 255)
    @Column(name = "address")
    private String address;
    @Size(max = 20)
    @Column(name = "nic")
    private String nic;
    @Basic(optional = false)
    @NotNull
    @Column(name = "regdate")
    @Temporal(TemporalType.DATE)
    private Date regdate;
    @Basic(optional = false)
    @NotNull
    @Column(name = "dob")
    @Temporal(TemporalType.DATE)
    private Date dob;
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 45)
    @Column(name = "lastname")
    private String lastname;
    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 25)
    @Column(name = "city")
    private String city;
    @OneToMany(cascade = CascadeType.ALL, mappedBy = "personid")
    private Collection<Patient> patientCollection;

    public Person() {
    }

    public Person(Integer id) {
        this.id = id;
    }

    public Person(Integer id, String firstname, Date regdate, Date dob, String lastname, String city) {
        this.id = id;
        this.firstname = firstname;
        this.regdate = regdate;
        this.dob = dob;
        this.lastname = lastname;
        this.city = city;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getFirstname() {
        return firstname;
    }

    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getMobile() {
        return mobile;
    }

    public void setMobile(String mobile) {
        this.mobile = mobile;
    }

    public String getResidence() {
        return residence;
    }

    public void setResidence(String residence) {
        this.residence = residence;
    }

    public String getOffice() {
        return office;
    }

    public void setOffice(String office) {
        this.office = office;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getNic() {
        return nic;
    }

    public void setNic(String nic) {
        this.nic = nic;
    }

    public Date getRegdate() {
        return regdate;
    }

    public void setRegdate(Date regdate) {
        this.regdate = regdate;
    }

    public Date getDob() {
        return dob;
    }

    public void setDob(Date dob) {
        this.dob = dob;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    @XmlTransient
    public Collection<Patient> getPatientCollection() {
        return patientCollection;
    }

    public void setPatientCollection(Collection<Patient> patientCollection) {
        this.patientCollection = patientCollection;
    }


}

Patient.java

package entity;

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;

@Entity
@Table(name = "patient")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Patient.findAll", query = "SELECT p FROM Patient p"),
@NamedQuery(name = "Patient.findById", query = "SELECT p FROM Patient p WHERE p.id = :id"),
@NamedQuery(name = "Patient.findByPatientcode", query = "SELECT p FROM Patient p WHERE p.patientcode = :patientcode"),
@NamedQuery(name = "Patient.findByHistory", query = "SELECT p FROM Patient p WHERE p.history = :history"),
@NamedQuery(name = "Patient.findByExtPatientCode", query = "SELECT p FROM Patient p    WHERE p.extPatientCode = :extPatientCode")})
public class Patient implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id")
private Integer id;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 20)
@Column(name = "patientcode")
private String patientcode;
@Size(max = 255)
@Column(name = "history")
private String history;
@Size(max = 20)
@Column(name = "ExtPatientCode")
private String extPatientCode;
@JoinColumn(name = "personid", referencedColumnName = "id")
@ManyToOne(optional = false)
private Person personid;

public Patient() {
}

public Patient(Integer id) {
    this.id = id;
}

public Patient(Integer id, String patientcode) {
    this.id = id;
    this.patientcode = patientcode;
}

public Integer getId() {
    return id;
}

public void setId(Integer id) {
    this.id = id;
}

public String getPatientcode() {
    return patientcode;
}

public void setPatientcode(String patientcode) {
    this.patientcode = patientcode;
}

public String getHistory() {
    return history;
}

public void setHistory(String history) {
    this.history = history;
}

public String getExtPatientCode() {
    return extPatientCode;
}

public void setExtPatientCode(String extPatientCode) {
    this.extPatientCode = extPatientCode;
}

public Person getPersonid() {
    return personid;
}

public void setPersonid(Person personid) {
    this.personid = personid;
}    

}

AbstractFacade.java

package session;

import java.util.List;
import javax.persistence.EntityManager;

public abstract class AbstractFacade<T> {
private Class<T> entityClass;

public AbstractFacade(Class<T> entityClass) {
    this.entityClass = entityClass;
}

protected abstract EntityManager getEntityManager();

public void create(T entity) {
    getEntityManager().persist(entity);
}

public void edit(T entity) {
    getEntityManager().merge(entity);
}

public void remove(T entity) {
    getEntityManager().remove(getEntityManager().merge(entity));
}

public T find(Object id) {
    return getEntityManager().find(entityClass, id);
}

public List<T> findAll() {
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    cq.select(cq.from(entityClass));
    return getEntityManager().createQuery(cq).getResultList();
}

public List<T> findRange(int[] range) {
    javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
    cq.select(cq.from(entityClass));
    javax.persistence.Query q = getEntityManager().createQuery(cq);
    q.setMaxResults(range[1] - range[0]);
    q.setFirstResult(range[0]);
    return q.getResultList();
}

}

PatientFacade.java

package session;

import entity.Patient;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Stateless
public class PatientFacade extends AbstractFacade<Patient> {
@PersistenceContext(unitName = "WebApplication4PU")
private EntityManager em;

@Override
protected EntityManager getEntityManager() {
    return em;
}

public PatientFacade() {
    super(Patient.class);
}

}

PersonFacade.java

package session;

import entity.Person;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;


@Stateless
public class PersonFacade extends AbstractFacade<Person> {
@PersistenceContext(unitName = "WebApplication4PU")
private EntityManager em;

@Override
protected EntityManager getEntityManager() {
    return em;
}

public PersonFacade() {
    super(Person.class);
}

}

PersonController.java

    package controllers;

import entity.Person;
import controllers.util.JsfUtil;
import controllers.util.PaginationHelper;
import session.PersonFacade;

import java.io.Serializable;
import java.util.ResourceBundle;
import javax.ejb.EJB;
import javax.inject.Named;
import javax.enterprise.context.SessionScoped;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;
import javax.faces.model.DataModel;
import javax.faces.model.ListDataModel;
import javax.faces.model.SelectItem;

@Named("personController")
@SessionScoped
public class PersonController implements Serializable {

    private Person current;
    private DataModel items = null;
    @EJB
    private session.PersonFacade ejbFacade;
    private PaginationHelper pagination;
    private int selectedItemIndex;

    public PersonController() {
    }

    public Person getSelected() {
        if (current == null) {
            current = new Person();
            selectedItemIndex = -1;
        }
        return current;
    }

    private PersonFacade getFacade() {
        return ejbFacade;
    }

    public PaginationHelper getPagination() {
        if (pagination == null) {
            pagination = new PaginationHelper(10) {
                @Override
                public int getItemsCount() {
                    return getFacade().count();
                }

                @Override
                public DataModel createPageDataModel() {
                    return new ListDataModel(getFacade().findRange(new int[]{getPageFirstItem(), getPageFirstItem() + getPageSize()}));
                }
            };
        }
        return pagination;
    }

    public String prepareList() {
        recreateModel();
        return "List";
    }

    public String prepareView() {
        current = (Person) getItems().getRowData();
        selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex();
        return "View";
    }

    public String prepareCreate() {
        current = new Person();
        selectedItemIndex = -1;
        return "Create";
    }

    public String create() {
        try {
            getFacade().create(current);
            JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("PersonCreated"));
            return prepareCreate();
        } catch (Exception e) {
            JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));
            return null;
        }
    }

    public String prepareEdit() {
        current = (Person) getItems().getRowData();
        selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex();
        return "Edit";
    }

    public String update() {
        try {
            getFacade().edit(current);
            JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("PersonUpdated"));
            return "View";
        } catch (Exception e) {
            JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));
            return null;
        }
    }

    public String destroy() {
        current = (Person) getItems().getRowData();
        selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex();
        performDestroy();
        recreatePagination();
        recreateModel();
        return "List";
    }

    public String destroyAndView() {
        performDestroy();
        recreateModel();
        updateCurrentItem();
        if (selectedItemIndex >= 0) {
            return "View";
        } else {
            // all items were removed - go back to list
            recreateModel();
            return "List";
        }
    }

    private void performDestroy() {
        try {
            getFacade().remove(current);
            JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("PersonDeleted"));
        } catch (Exception e) {
            JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));
        }
    }

    private void updateCurrentItem() {
        int count = getFacade().count();
        if (selectedItemIndex >= count) {
            // selected index cannot be bigger than number of items:
            selectedItemIndex = count - 1;
            // go to previous page if last page disappeared:
            if (pagination.getPageFirstItem() >= count) {
                pagination.previousPage();
            }
        }
        if (selectedItemIndex >= 0) {
            current = getFacade().findRange(new int[]{selectedItemIndex, selectedItemIndex + 1}).get(0);
        }
    }

    public DataModel getItems() {
        if (items == null) {
            items = getPagination().createPageDataModel();
        }
        return items;
    }

    private void recreateModel() {
        items = null;
    }

    private void recreatePagination() {
        pagination = null;
    }

    public String next() {
        getPagination().nextPage();
        recreateModel();
        return "List";
    }

    public String previous() {
        getPagination().previousPage();
        recreateModel();
        return "List";
    }

    public SelectItem[] getItemsAvailableSelectMany() {
        return JsfUtil.getSelectItems(ejbFacade.findAll(), false);
    }

    public SelectItem[] getItemsAvailableSelectOne() {
        return JsfUtil.getSelectItems(ejbFacade.findAll(), true);
    }

    public Person getPerson(java.lang.Integer id) {
        return ejbFacade.find(id);
    }

    @FacesConverter(forClass = Person.class)
    public static class PersonControllerConverter implements Converter {

        @Override
        public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
            if (value == null || value.length() == 0) {
                return null;
            }
            PersonController controller = (PersonController) facesContext.getApplication().getELResolver().
                    getValue(facesContext.getELContext(), null, "personController");
            return controller.getPerson(getKey(value));
        }

        java.lang.Integer getKey(String value) {
            java.lang.Integer key;
            key = Integer.valueOf(value);
            return key;
        }

        String getStringKey(java.lang.Integer value) {
            StringBuilder sb = new StringBuilder();
            sb.append(value);
            return sb.toString();
        }


    }
}

PatientController.java

    package controllers;

import entity.Patient;
import controllers.util.JsfUtil;
import controllers.util.PaginationHelper;
import session.PatientFacade;

import java.io.Serializable;
import java.util.ResourceBundle;
import javax.ejb.EJB;
import javax.inject.Named;
import javax.enterprise.context.SessionScoped;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;
import javax.faces.model.DataModel;
import javax.faces.model.ListDataModel;
import javax.faces.model.SelectItem;

@Named("patientController")
@SessionScoped
public class PatientController implements Serializable {

    private Patient current;
    private DataModel items = null;
    @EJB
    private session.PatientFacade ejbFacade;
    private PaginationHelper pagination;
    private int selectedItemIndex;

    public PatientController() {
    }

    public Patient getSelected() {
        if (current == null) {
            current = new Patient();
            selectedItemIndex = -1;
        }
        return current;
    }

    private PatientFacade getFacade() {
        return ejbFacade;
    }

    public PaginationHelper getPagination() {
        if (pagination == null) {
            pagination = new PaginationHelper(10) {
                @Override
                public int getItemsCount() {
                    return getFacade().count();
                }

                @Override
                public DataModel createPageDataModel() {
                    return new ListDataModel(getFacade().findRange(new int[]{getPageFirstItem(), getPageFirstItem() + getPageSize()}));
                }
            };
        }
        return pagination;
    }

    public String prepareList() {
        recreateModel();
        return "List";
    }

    public String prepareView() {
        current = (Patient) getItems().getRowData();
        selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex();
        return "View";
    }

    public String prepareCreate() {
        current = new Patient();
        selectedItemIndex = -1;
        return "Create";
    }

    public String create() {
        try {
            getFacade().create(current);
            JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("PatientCreated"));
            return prepareCreate();
        } catch (Exception e) {
            JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));
            return null;
        }
    }

    public String prepareEdit() {
        current = (Patient) getItems().getRowData();
        selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex();
        return "Edit";
    }

    public String update() {
        try {
            getFacade().edit(current);
            JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("PatientUpdated"));
            return "View";
        } catch (Exception e) {
            JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));
            return null;
        }
    }

    public String destroy() {
        current = (Patient) getItems().getRowData();
        selectedItemIndex = pagination.getPageFirstItem() + getItems().getRowIndex();
        performDestroy();
        recreatePagination();
        recreateModel();
        return "List";
    }

    public String destroyAndView() {
        performDestroy();
        recreateModel();
        updateCurrentItem();
        if (selectedItemIndex >= 0) {
            return "View";
        } else {
            // all items were removed - go back to list
            recreateModel();
            return "List";
        }
    }

    private void performDestroy() {
        try {
            getFacade().remove(current);
            JsfUtil.addSuccessMessage(ResourceBundle.getBundle("/Bundle").getString("PatientDeleted"));
        } catch (Exception e) {
            JsfUtil.addErrorMessage(e, ResourceBundle.getBundle("/Bundle").getString("PersistenceErrorOccured"));
        }
    }

    private void updateCurrentItem() {
        int count = getFacade().count();
        if (selectedItemIndex >= count) {
            // selected index cannot be bigger than number of items:
            selectedItemIndex = count - 1;
            // go to previous page if last page disappeared:
            if (pagination.getPageFirstItem() >= count) {
                pagination.previousPage();
            }
        }
        if (selectedItemIndex >= 0) {
            current = getFacade().findRange(new int[]{selectedItemIndex, selectedItemIndex + 1}).get(0);
        }
    }

    public DataModel getItems() {
        if (items == null) {
            items = getPagination().createPageDataModel();
        }
        return items;
    }

    private void recreateModel() {
        items = null;
    }

    private void recreatePagination() {
        pagination = null;
    }

    public String next() {
        getPagination().nextPage();
        recreateModel();
        return "List";
    }

    public String previous() {
        getPagination().previousPage();
        recreateModel();
        return "List";
    }

    public SelectItem[] getItemsAvailableSelectMany() {
        return JsfUtil.getSelectItems(ejbFacade.findAll(), false);
    }

    public SelectItem[] getItemsAvailableSelectOne() {
        return JsfUtil.getSelectItems(ejbFacade.findAll(), true);
    }

    public Patient getPatient(java.lang.Integer id) {
        return ejbFacade.find(id);
    }

    @FacesConverter(forClass = Patient.class)
    public static class PatientControllerConverter implements Converter {

        @Override
        public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
            if (value == null || value.length() == 0) {
                return null;
            }
            PatientController controller = (PatientController) facesContext.getApplication().getELResolver().
                    getValue(facesContext.getELContext(), null, "patientController");
            return controller.getPatient(getKey(value));
        }

        java.lang.Integer getKey(String value) {
            java.lang.Integer key;
            key = Integer.valueOf(value);
            return key;
        }

        String getStringKey(java.lang.Integer value) {
            StringBuilder sb = new StringBuilder();
            sb.append(value);
            return sb.toString();
        }

        @Override
        public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
            if (object == null) {
                return null;
            }
            if (object instanceof Patient) {
                Patient o = (Patient) object;
                return getStringKey(o.getId());
            } else {
                throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected type: " + Patient.class.getName());
            }
        }
    }
}

Thanks in advance.

Answer 1

Fact: a single @Stateless EJB method call counts as a single full transaction.

Just make use of this fact. Create a new method in the @Stateless EJB which executes all necessary queries at once and then let your JSF backing bean call exactly that single method.

That's by the way exactly one of main reasons why EJBs exist: transparent transaction management. You seem to have missed this not unimportant fact while learning Java EE.