Hi:
Has anyone figured out the use of generated long id in @PrinaryKey to
build a complete key graph. If not possible, what is the best technique
to generate long id for a complete graph of parent-child relationship.
Following is a use case:
UserOrg is the root entity with userId = "f...@budhnet.com" which
generate a 'message' sent to a list of receivers.
public class UserOrg {
@PrimaryKey private Key rootKey;
// the key is generated as
rootKey = KeyFactory.createdKey(UserOrg.class.getSimpleName(),
userId);
public class Message { //whose instance is generated by a userId
@PrimaryKey private Key messageKey;
// can the key be generated as one of the 2 followings
messageKey = new KeyFactory.Builder(UserOrg.class.getSimpleName(),
userId).addChild(Message.class.getSimpleName(), messageKey.getId
()).getKey();
or Key rootKey = KeyFactory.createKey(UserOrg.class.getSimpleName(),
userId);
messageKey = KeyFactory.createKey(rootKey, MessageClass.getSimpleName
(), rootKey.getChild().getId());
If not, what is the best practice in generating the long id for child
message of a userId. Same thing would apply for the MessageIndex of
receiver list.
public class MessageIndex { // child of the message created by userId
Key rootKey = KeyFactory.createKey(UserOrg.class.getSimpleName(),
userId);
messageKey = KeyFactory.createKey(rootKey, MessageClass.getSimpleName
(), rootKey.getChild().getId());
@PrimaryKey private Key messageIndexKey;
messageIndexKey = KeyFactory.createKey(messageKey,
MessageIndex.class.getSimpleName(), messageKey.getChild().getId());
The exercise is getting more complex for set intersection as shown in
python in
http://code.google.com/events/io/2009/sessions/BuildingScalableComplexApps.html
Has anyone worked out the Java code of the demos? the author?
Thanks
Duong BaTien
DBGROUPS and BudhNet
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