How to construct query with null parameters in jpa 2.0

Question

Hi,
I am creating a jpa 2.0 application. I have an entity with a large number of fields
@Entity
@Table(name="notations")
public class Notation implements Serializable {
     private static final long serialVersionUID = 1L;
     @Id
     private Integer id;
     @Column(name="action_count")
     private Integer actionCount;
     @Column(name="adaptability_comment")
     private String adaptabilityComment;
     @Column(name="adaptability_score")
     private Integer adaptabilityScore;
     private String comment;
     @Column(name="compatibility_comment")
     private String compatibilityComment;
     @Column(name="compatibility_score")
     private Integer compatibilityScore;
     @Column(name="consistency_comment")
     private String consistencyComment;
     @Column(name="consistency_score")
     private Integer consistencyScore;
     @Column(name="controlpoint_name")
     private String controlpointName;
     @Column(name="device_brand")
     private String deviceBrand;
     @Column(name="device_name")
     private String deviceName;
     @Column(name="error_management_comment")
     private String errorManagementComment;
     @Column(name="error_management_score")
     private Integer errorManagementScore;
     @Column(name="explicit_control_comment")
     private String explicitControlComment;
     @Column(name="explicit_control_score")
     private Integer explicitControlScore;
     @Column(name="functionality_name")
     private String functionalityName;
     @Column(name="guidance_comment")
     private String guidanceComment;
     @Column(name="guidance_score")
     private Integer guidanceScore;
     @Column(name="is_available")
     private Boolean isAvailable;
     private String protocol;
     @Column(name="significance_comment")
     private String significanceComment;
     @Column(name="significance_score")
     private Integer significanceScore;
     @Column(name="tester_name")
     private String testerName;
     @Column(name="use_case_name")
     private String useCaseName;
     @Column(name="workload_comment")
     private String workloadComment;
     @Column(name="workload_score")
     private Integer workloadScore;
        getters, settersI am using a method to update this entity as the user changes different fields. My method takes (almost) all fields, but only one (or few) have values, the others are null.
public Notation updateNotation(Integer id, Boolean isAvailable, String protocol, String deviceBrand,
               String deviceName,String testerName, Date ratingDate, String functionalityName,
               String useCaseName,     String controlPointName, Integer actionCount, String comment,
               Integer adaptabilityScore, Integer compatibilityScore, Integer consistencyScore,
               Integer errorManagementScore, Integer explicitControlScore, Integer guidanceScore, Integer significanceScore,
               Integer workloadScore, String adaptabilityComment, String compatibilityComment,
               String consistencyComment, String errorManagementComment, String explicitControlComment,
               String guidanceComment, String significanceComment, String workloadComment) throws PersistenceException{
          String setString = "";
          if(isAvailable != null)
               setString += "n.isAvailable = '" + isAvailable + "',";
          if(!(protocol==null||protocol.isEmpty()))
               setString += "n.protocol = '" + protocol + "',";
          if(!(deviceBrand==null||deviceBrand.isEmpty()))
               setString += "n.deviceBrand = '" + deviceBrand + "',";
          if(!(deviceName==null||deviceName.isEmpty()))
               setString += "n.deviceName = '" + deviceName + "',";
          if(!(testerName==null||testerName.isEmpty()))
               setString += "n.testerName = '" + testerName + "',";
          if(!(functionalityName==null||functionalityName.isEmpty()))
               setString += "n.functionalityName = '" + functionalityName + "',";
          if(!(useCaseName==null||useCaseName.isEmpty()))
               setString += "n.useCaseName = '" + useCaseName + "',";
          if(!(controlPointName==null||controlPointName.isEmpty()))
               setString += "n.controlPointName = '" + controlPointName + "',";
          if(actionCount != null)
               setString += "n.actionCount = '" + actionCount + "',";
          if(!(comment==null||comment.isEmpty()))
               setString += "n.comment = '" + comment + "',";
          if(adaptabilityScore != null)
               setString += "n.adaptabilityScore = '" + adaptabilityScore + "',";
          if(compatibilityScore != null)
               setString += "n.compatibilityScore = '" + compatibilityScore + "',";
          if(consistencyScore != null)
               setString += "n.consistencyScore = '" + consistencyScore + "',";
          if(errorManagementScore != null)
               setString += "n.errorManagementScore = '" + errorManagementScore + "',";
          if(explicitControlScore != null)
               setString += "n.explicitControlScore = '" + explicitControlScore + "',";
          if(guidanceScore != null)
               setString += "n.guidanceScore = '" + guidanceScore + "',";
          if(significanceScore != null)
               setString += "n.significanceScore = '" + significanceScore + "',";
          if(workloadScore != null)
               setString += "n.workloadScore = '" + workloadScore + "',";
          if(!(adaptabilityComment==null||adaptabilityComment.isEmpty()))
               setString += "n.adaptabilityComment = '" + adaptabilityComment + "',";
          if(!(compatibilityComment==null||compatibilityComment.isEmpty()))
               setString += "n.compatibilityComment = '" + compatibilityComment + "',";
          if(!(consistencyComment==null||consistencyComment.isEmpty()))
               setString += "n.consistencyComment = '" + consistencyComment + "',";
          if(!(errorManagementComment==null||errorManagementComment.isEmpty()))
               setString += "n.errorManagementComment = '" + errorManagementComment + "',";
          if(!(explicitControlComment==null||explicitControlComment.isEmpty()))
               setString += "n.explicitControlComment = '" + explicitControlComment + "',";
          if(!(guidanceComment==null||guidanceComment.isEmpty()))
               setString += "n.guidanceComment = '" + guidanceComment + "',";
          if(!(significanceComment==null||significanceComment.isEmpty()))
               setString += "n.significanceComment = '" + significanceComment + "',";
          if(!(workloadComment==null||workloadComment.isEmpty()))
               setString += "n.workloadComment = '" + workloadComment + "',";
          if(setString!="") setString = setString.substring(0, setString.length()-1);
          String queryString = "UPDATE Notation n SET " + setString + " WHERE n.id = ?1";
          Query q = em.createQuery(queryString);
          q.setParameter(1, id);
          q.executeUpdate();
          return (Notation) em.createQuery("SELECT n FROM Notation n WHERE n.id = ?1").setParameter(1, id).getResultList().get(0);
     }So my question I think is somewhat obvious. What is a good way to construct my query, so that I am not forced to have such an ugly and laborious code (again, knowing that most of the arguments are null)?
Thanks in advance
Edited by: StefanC on Jan 27, 2010 3:01 AM

Answer 1

That is a good point, I will do the operations directly on the entity. However, that still doesn't save me from having to write all those if statements and having an ugly code.
Husain.AlKhamis wrote:
Exactly, this is the concept behind JPA --> you have to write zero SQL queries.It's true that you don't have to write any queries for update and remove, however you still have to write JPQL queries (pretty much like SQL) to selections.