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1 package com.db4o.f1.chapter4;
2
3 import java.io.*;
4 import java.util.Arrays  ;
5
6 import com.db4o.*;
7 import com.db4o.f1.*;
8 import com.db4o.query.*;
9
10
11 public class InheritanceExample extends Util {
12 public static void main(String [] args) {
13 new File(Util.YAPFILENAME).delete();
14 ObjectContainer db=Db4o.openFile(Util.YAPFILENAME);
15 try {
16 storeFirstCar(db);
17 storeSecondCar(db);
18 retrieveTemperatureReadoutsQBE(db);
19 retrieveAllSensorReadoutsQBE(db);
20 retrieveAllSensorReadoutsQBEAlternative(db);
21 retrieveAllSensorReadoutsQuery(db);
22 retrieveAllObjectsQBE(db);
23 }
24 finally {
25 db.close();
26 }
27 }
28
29 public static void storeFirstCar(ObjectContainer db) {
30 Car car1=new Car("Ferrari");
31 Pilot pilot1=new Pilot("Michael Schumacher",100);
32 car1.setPilot(pilot1);
33 db.set(car1);
34 }
35
36 public static void storeSecondCar(ObjectContainer db) {
37 Pilot pilot2=new Pilot("Rubens Barrichello",99);
38 Car car2=new Car("BMW");
39 car2.setPilot(pilot2);
40 car2.snapshot();
41 car2.snapshot();
42 db.set(car2);
43 }
44
45 public static void retrieveAllSensorReadoutsQBE(
46 ObjectContainer db) {
47 SensorReadout proto=new SensorReadout(null,null,null);
48 ObjectSet result=db.get(proto);
49 listResult(result);
50 }
51
52 public static void retrieveTemperatureReadoutsQBE(
53 ObjectContainer db) {
54 SensorReadout proto=
55 new TemperatureSensorReadout(null,null,null,0.0);
56 ObjectSet result=db.get(proto);
57 listResult(result);
58 }
59
60 public static void retrieveAllSensorReadoutsQBEAlternative(
61 ObjectContainer db) {
62 ObjectSet result=db.get(SensorReadout.class);
63 listResult(result);
64 }
65
66 public static void retrieveAllSensorReadoutsQuery(
67 ObjectContainer db) {
68 Query query=db.query();
69 query.constrain(SensorReadout.class);
70 ObjectSet result=query.execute();
71 listResult(result);
72 }
73
74 public static void retrieveAllObjectsQBE(ObjectContainer db) {
75 ObjectSet result=db.get(new Object ());
76 listResult(result);
77 }
78
79 }
80 |
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Java API By Example, From Geeks To Geeks.