package fr.valtech.many2many.domain;
 
import java.util.HashSet;
import java.util.Set;
 
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
 
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
 
@Entity
@Table(name = "recipe")
@EqualsAndHashCode(of = { "id", "title" }, callSuper = false)
public class Recipe extends AbstractEntity {
 
  @Id
  @Column(name = "recipe_id")
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Getter
  @Setter
  private Integer id;
 
  @Getter
  @Setter
  private String title;
 
  @Getter
  @Setter
  @OneToMany(fetch = FetchType.EAGER, mappedBy = "pk.recipe", cascade = CascadeType.ALL, orphanRemoval = true)
  private Set ingredients = new HashSet();
 
  public void addIngredient(RecipeIngredient i) {
    i.setRecipe(this);
    ingredients.add(i);
  }
}

package fr.valtech.many2many.domain;
 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
 
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
 
@Entity
@EqualsAndHashCode(of = { "id", "label" }, callSuper = false)
public class Ingredient extends AbstractEntity {
 
    @Id
    @Column(name = "ingredient_id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Getter
    @Setter
    private Integer id;
 
    @Getter
    @Setter
    private String label;
 
}

package fr.valtech.many2many.domain;
 
import java.io.Serializable;
 
import javax.persistence.AssociationOverride;
import javax.persistence.AssociationOverrides;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.JoinColumn;
import javax.persistence.Table;
import javax.persistence.Transient;
 
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
 
@Entity
@Table(name = "recipe_ingredient")
@AssociationOverrides({
        @AssociationOverride(name = "pk.recipe", joinColumns = @JoinColumn(name = "recipe_id", insertable = false, updatable = false)),
        @AssociationOverride(name = "pk.ingredient", joinColumns = @JoinColumn(name = "ingredient_id", insertable = false, updatable = false)) })
@EqualsAndHashCode(of = { "pk", "amount" }, callSuper = false)
public class RecipeIngredient implements Serializable {
 
    @Getter
    @Setter
    @Column(nullable = false)
    private String amount;
 
    @Getter
    @Setter
    @EmbeddedId
    private RecipeIngredientId pk = new RecipeIngredientId();
 
    @Transient
    public Recipe getRecipe() {
        return getPk().getRecipe();
    }
 
    public void setRecipe(Recipe recipe) {
        getPk().setRecipe(recipe);
    }
 
    @Transient
    public Ingredient getIngredient() {
        return getPk().getIngredient();
    }
 
    public void setIngredient(Ingredient ingredient) {
        getPk().setIngredient(ingredient);
    }
 
    public RecipeIngredient() {
    }
 
    public RecipeIngredient(Ingredient ingredient, String amount) {
        setIngredient(ingredient);
        this.amount = amount;
    }
 
}

package fr.valtech.many2many.domain;
 
import java.io.Serializable;
 
import javax.persistence.CascadeType;
import javax.persistence.Embeddable;
import javax.persistence.FetchType;
import javax.persistence.ManyToOne;
 
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
 
@Embeddable
@EqualsAndHashCode(of = { "recipe", "ingredient" }, callSuper = false)
public class RecipeIngredientId implements Serializable {
 
    @Getter
    @Setter
    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    private Recipe recipe;
 
    @Getter
    @Setter
    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    private Ingredient ingredient;
 
}

    /**
     * Parcourt l'ensemble des ingrédient pour voir si ils existe déjà en base ou non.
     * @param recipe
     */
    private void reatachIngredients(Recipe recipe) {
 
        for (Iterator it = recipe.getRecipeIngredients()
                .iterator(); it.hasNext();) {
            RecipeIngredient ri = it.next();
            Ingredient ingredient = ri.getIngredient();
            if (ingredient.getId() != null && ingredient.getId() != 0) {
                Ingredient reference = getEntityManager().getReference(
                        Ingredient.class, ingredient.getId());
                ri.setIngredient(reference);
            } else {
                getEntityManager().persist(ingredient);
            }
        }
    }

        Query q = getEntityManager().createQuery(
                "select r from Recipe as r "
                        + "left join fetch r.recipeIngredients as ri "
                        + "left join fetch ri.pk as pk "
                        + "left join fetch pk.ingredient "
                        + "where r.id = :recipeId");
 
        q.setParameter("recipeId", recipeId);
 
        Recipe recipe = null;
        try {
            recipe = (Recipe) q.getSingleResult();
        } catch (NoResultException nre) {
            getLogger().info("no result found");
            return null;
        }