下面是代码
@PersistenceCapable
public class Objective {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private boolean active;
@Persistent
private int corporate;
@Persistent
private String nameOfObjective;
@Persistent
private String shortDescription;
@Persistent
private int status;
@Persistent
private List<Key> scoreCardKeys; //List of Keys of Scorecards.
@PersistenceCapable
public class Scorecard {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private boolean active;
@Persistent
private int corporate; // synonymous to being public
@Persistent
private Date creationDate;
@Persistent
private String nameOfScorecard;
@Persistent
private String shortDescription;
@Persistent
private Key createdUserKey;
@Persistent
private List<Key> objectiveKeys; // List of Keys of Objectives
目的和记分卡实体是无主的多对多关系
这里是处理器的方法,其将更新记分卡。
public ScoreCardRepresentation updateScoreCard(ScoreCardRepresentation scoreCardRepresentation) {
Scorecard scoreCard = scoreCardTransformer
.transformRtoEForSave(scoreCardRepresentation);
scoreCard.setCreationDate(new Date());
Scorecard updatedScoreCard = scoreCardDAO.saveScoreCard(scoreCard); /* Update the scorecard, this already has the list of Key of Objectives in it, Hence blindly save it. */
/* Update the Key of the scorecard in the Objectives too */
updateRelatedObjectivesToScoreCard(scoreCardRepresentation,updatedScoreCard);
private void updateRelatedObjectivesToScoreCard(
ScoreCardRepresentation scoreCardRepresentation,
Scorecard updatedScoreCard) {
List<String> addedObjectivesIds = scoreCardRepresentation.getAddedObjectiveKeys();
List<String> deletedObjectivesIds = scoreCardRepresentation.getRemovedObjectiveKeys();
// Add ScoreCard to the newly added Objectives
if(addedObjectivesIds != null && addedObjectivesIds.size()>0){
Scorecard sc = scoreCardDAO.findScoreCardById(Scorecard.class, updatedScoreCard.getKey());
List<Key> objKeys = sc.getObjectiveKeys();
List<Objective> objectives = objectiveDAO.findObjectivesByKeys(Objective.class,objKeys);
//它使用查询从选择 “+ clazz.getName()+” 其中:keys.contains(键)
for(Objective obj : objectives){
List<Key> scoreCardKeys = obj.getScoreCardKeys();
if(scoreCardKeys != null){
scoreCardKeys.add(sc.getKey());
} else {
scoreCardKeys = new ArrayList<Key>();
scoreCardKeys.add(sc.getKey());
}
obj.setScoreCardKeys(scoreCardKeys);
Objective updatedObjective = objectiveDAO.saveObjective(obj);
System.out.println(new ObjectiveProcessor().viewObjective(KeyFactory.keyToString(obj.getKey())));
}
}
//Remove Scorecard entries from Objective.
if(deletedObjectivesIds != null && deletedObjectivesIds.size()>0){
List<Objective> objectives = objectiveDAO.findObjectivesByIds(Objective.class,deletedObjectivesIds);
for(Objective obj : objectives){
List<Key> scoreCardKeys = obj.getScoreCardKeys();
if(scoreCardKeys != null){
scoreCardKeys.remove(updatedScoreCard.getKey());
}
obj.setScoreCardKeys(scoreCardKeys);
}
}
}
所有我已经能够认识到的是,当我使用**findObjectivesByKeys**
取回目标我正在回到空心物体,所以我必须调用makeTransient对它们进行持久化,否则它们只会忽略makePersistent方法调用。
另外我注意到的是我回到中空状态的物体。我必须给他们打电话maketransient更新他们吗? – Hrishikesh
如果你不提供持久代码,你不能指望任何人明白这一点。而GAE v1并没有做适当的“无主”关系;它只是使用Key字段进行破解。 – DataNucleus
好的,这是我的代码... – Hrishikesh