How to use list properties in Google App Engine data store in Java?

Objects placed in the data store will have a set of tags

public class Model 
{
    List<String> tagList
    ...
}

In Python, Google App Engine has the concept of list attribute Equivalent concepts in Java (if any) and how to use list attributes in Java, JPA and / or JDO?

Solution

Please refer to my blog post: efficient keyword search with relation index entities and objectify for Google datastore It discusses the use of relational index entities and objectify to search list attributes

To sum up:

Query<DocumentKeywords> query = ofy.query(DocumentKeywords.class);
  for (String keyword : keywords) {
    query = query.filter("keywords",keyword);
  }

  Set<Key<Document>> keys = query.<Document>fetchParentKeys();

  Collection<Document> documents = ofy.get(keys).values();

Where documentkeywords contains the list attribute (Collection) of all keywords of its document entity, and the document entity is the parent of documentkeywords

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