google app engine - How to filter in datastore using objectify for a Date property ? -

How to filter the datestore using the object for the date property? I have an institution that looks under the piege class. At this time the stamp is a property which holds the date value.

  Public Class Travel Entry {Private String Device ID; Guadatata to the private string; Private string location; Private Deadly Timestamp; Public Travel Entry () {setTimeStamp (this.timeStamp); } Public string getDeviceId () {return deviceId; } Public Zero Set Device ID (string device id) {this.deviceId = deviceId; } Public string getPushedGeoData () {return pushGoData; } Public Zero Set PushedGeoData (string pushGeoData) {this pushgeoData = pushGeoData; } Public string getLocation () {return location; } Public Zero Set Location (string location) {this.location = location; } Public Date getTimeStamp () {Time return stamp; } Public Zero Settimestamp (Date Timestamp) {if (Timestamp == empty) {this.timeStamp = new date (); } And {this.timeStamp = timeStamp; }}}  

How do I query or filter a date property using an object? I want to retrieve all those institutions which are of those special dates and times.

It is described in all documents:

Filter by the @ index field and then the desired date value.