java - Loaded Entity has parent but has no @Parent -

i have following schema, using objectify

@entity public class book{   @id   private long id;   private key<page> pages;   …  }  @entity  public class page{   @id   private string id;   …    public page(book book,int pagenumber){     this.id = book.getid()+””+pagenumber;      …   }  } 

i getting complaint

com.googlecode.objectify.loadexception: error loading book(1401058017250)/page("14010580172505639445604728832"): loaded entity has parent com.company.api.db.page has no @parent

caused by: java.lang.illegalstateexception: loaded entity has parent com.company.api.db.page has no @parent

i coming eclipse , datanucleus , in framework code was

@entity public class book{   @id   private long id;   private list<page> pages;   …  }  @entity  public class page{   @id   private key key;   …    public page(book book,int pagenumber){     this.key = createkey(book.getid(),pagenumber);      …   }  private key createkey(long bookid, long pagenumber) {     key bookkey = keyfactory.createkey(book.class.getsimplename(), bookid);     key key = keyfactory.createkey(bookkey, page.class.getsimplename(), bookid + "" + pagenumber);     return key;   }  } 

whether best code or not, used work. anyway, migrating objectify , android studio. how rewrite schema stop getting error? if know answer, please copy , paste code snippet , make appropriate edits.

in old code, you're marking bookkey parent entity. in new code, need have:

@parent key<book> parentbook; 

your new classes should be:

@entity public class book{   @id   private long id;   private list<key<page>> pages;   … }  @entity  public class page{   @id   private string id;   @parent   key<book> parentbook;   …    public page(long bookid, int pagenumber){     this.id = bookid + ”” +pagenumber;     this.parentbook = key.create(book.class, bookid);      …   }  } 

read more keys , objectify here: https://code.google.com/p/objectify-appengine/wiki/concepts#keys