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1 package com.db4o.f1.chapter6;
2
3 import java.io.*;
4
5 import com.db4o.*;
6 import com.db4o.f1.*;
7 import com.db4o.f1.chapter3.*;
8 import com.db4o.query.*;
9
10 public class EvaluationExample extends Util {
11 public static void main(String  [] args) {
12 new File(Util.YAPFILENAME).delete();
13 ObjectContainer db=Db4o.openFile(Util.YAPFILENAME);
14 try {
15 storeCars(db);
16 queryWithEvaluation(db);
17 }
18 finally {
19 db.close();
20 }
21 }
22
23 public static void storeCars(ObjectContainer db) {
24 Pilot pilot1=new Pilot("Michael Schumacher",100);
25 Car car1=new Car("Ferrari");
26 car1.setPilot(pilot1);
27 car1.snapshot();
28 db.set(car1);
29 Pilot pilot2=new Pilot("Rubens Barrichello",99);
30 Car car2=new Car("BMW");
31 car2.setPilot(pilot2);
32 car2.snapshot();
33 car2.snapshot();
34 db.set(car2);
35 }
36
37 public static void queryWithEvaluation(ObjectContainer db) {
38 Query query=db.query();
39 query.constrain(Car.class);
40 query.constrain(new EvenHistoryEvaluation());
41 ObjectSet result=query.execute();
42 Util.listResult(result);
43 }
44 }
45 |
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Java API By Example, From Geeks To Geeks.