CODEWITHSUNDEEP
google-app-enginegoogle-cloud-datastore
nightcrawler23
nightcrawler23

Reputation: 2066

java - appengnie code to get child entity from datastore not working

i have this code to check if a child entity already exists in datastore. The problem is that it works for one parent-child relation but always returns null for another relation.

i have four kind of entities in my app - ORG, Contact, Profile, ProfileOrg. Contact kind entities are children of ORG and ProfileOrg are children of Profile. The logic to add a contact to ORG is to get all childentities for the given org and then check for a property. if property matches i return the entity else null. this works perfectly for ORG-Contact relation. but the exact same logic for Profile-ProfileOrg relation doesnot work. it always returns null. Below is my code:

This is the code to get all childentities and check if its property "orgID" matches or not.

public static Entity getSingleProfileOrg(Key profileKey, String orgID) {

    Iterable<Entity> childProfileOrgs = Util.listChildren("profileOrg",profileKey);

    for (Entity e : childProfileOrgs) {
        if (e.getProperty("orgID").toString() == orgID) {
            return e;
        }
    }
    return null;
}

This is the code to query datastore.

public static Iterable<Entity> listChildren(String kind, Key ancestor) {
  logger.log(Level.INFO, "Search entities based on parent");
  Query query = new Query(kind);
  query.setAncestor(ancestor);
  query.addFilter(Entity.KEY_RESERVED_PROPERTY, FilterOperator.GREATER_THAN, ancestor);
  PreparedQuery pq = datastore.prepare(query);
  return pq.asIterable();
}

Please help. this has got me stuck.

Edit: Code for getting ChildEntities for org which works perfectly

public static Entity getSingleContact(Key orgKey, String phoneContactID) {
    Iterable<Entity> childContacts = Util.listChildren("contact", orgKey);


    for (Entity e : childContacts) {
        if (e.getProperty("contactID") == phoneContactID) {
            return e;
        }
    }
    return null;
}

Edit: Code to create or update ProfileOrg

public static void createOrUpdateProfileOrg(String profileID,
        String orgName, String ownerID) {
    String orgID = ownerID + "_" + orgName;
    Entity Profile = Product.getProfile(profileID);
    //Key profileKey = KeyFactory.createKey("Profile", profileID);
    Key profileKey = Profile.getKey();
    Entity profileOrg = getSingleProfileOrg(profileKey, orgID);
    if (profileOrg == null) {
        profileOrg = new Entity("profileOrg", profileKey);
        profileOrg.setProperty("name", orgName);
        profileOrg.setProperty("orgID", orgID);
        profileOrg.setProperty("owner", ownerID);
        profileOrg.setProperty("profileID", profileID);
        Util.persistEntity(profileOrg);
    }

}

the line

Entity Profile = Product.getProfile(profileID);

should be working fine as it is used to create profiles also and i dont see any problem there.

As i always get a null from getSingleProfileOrg(profileKey, orgID); i end up getting duplicate child entities.

Upvotes: 1

Views: 911

Answers (1)

Thanos Makris
Thanos Makris

Reputation: 3115

Since in listChildren, you want to query based an ancestor, your method is wrong. It should be like this:

public static Iterable<Entity> listChildren(String kind, Key ancestor) {
  logger.log(Level.INFO, "Search entities based on parent");
  Query query = new Query(kind);
  query.setAncestor(ancestor);
  PreparedQuery pq = datastore.prepare(query);
  return pq.asIterable();
}

Hope this helps.

Upvotes: 1

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