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1
2
3 package com.db4odoc.f1.identity;
4
5 import java.io.File  ;
6
7 import com.db4o.Db4o;
8 import com.db4o.ObjectContainer;
9 import com.db4o.ObjectSet;
10 import com.db4o.query.Query;
11 import com.db4odoc.f1.Util;
12
13 public class IdentityExample extends Util {
14
15
16 public static void main(String [] args) {
17 setObjects();
18 checkUniqueness();
19 checkReferenceCache();
20 checkReferenceCacheWithPurge();
21 testBind();
22
23 testCopyingWithPurge();
24 }
25
27 public static void setObjects(){
28 new File (Util.YAPFILENAME).delete();
29 ObjectContainer db = Db4o.openFile(Util.YAPFILENAME);
30 try {
31 Car car = new Car("BMW", new Pilot("Rubens Barrichello"));
32 db.set(car);
33 car = new Car("Ferrari", new Pilot("Michael Schumacher"));
34 db.set(car);
35 } finally {
36 db.close();
37 }
38 }
39
41 public static void checkUniqueness(){
42 setObjects();
43 ObjectContainer db = Db4o.openFile(Util.YAPFILENAME);
44 try {
45 ObjectSet cars = db.query(Car.class);
46 Car car = (Car)cars.get(0);
47 String pilotName = car.getPilot().getName();
48 ObjectSet pilots = db.get(new Pilot(pilotName));
49 Pilot pilot = (Pilot)pilots.get(0);
50 System.out.println("Retrieved objects are identical: " + (pilot == car.getPilot()));
51 } finally {
52 db.close();
53 }
54 }
55
57 public static void checkReferenceCache(){
58 setObjects();
59 ObjectContainer db = Db4o.openFile(Util.YAPFILENAME);
60 try {
61 ObjectSet pilots = db.query(Pilot.class);
62 Pilot pilot = (Pilot)pilots.get(0);
63 String pilotName = pilot.getName();
64 pilot.setName("new name");
65 System.out.println("Retrieving pilot by name: " + pilotName);
66 ObjectSet pilots1 = db.get(new Pilot(pilotName));
67 listResult(pilots1);
68 } finally {
69 db.close();
70 }
71 }
72
74 public static void checkReferenceCacheWithPurge(){
75 setObjects();
76 ObjectContainer db = Db4o.openFile(Util.YAPFILENAME);
77 try {
78 ObjectSet pilots = db.query(Pilot.class);
79 Pilot pilot = (Pilot)pilots.get(0);
80 String pilotName = pilot.getName();
81 pilot.setName("new name");
82 System.out.println("Retrieving pilot by name: " + pilotName);
83 long pilotID = db.ext().getID(pilot);
84 if (db.ext().isCached(pilotID)){
85 db.ext().purge(pilot);
86 }
87 ObjectSet pilots1 = db.get(new Pilot(pilotName));
88 listResult(pilots1);
89 } finally {
90 db.close();
91 }
92 }
93
95 public static void testCopyingWithPurge(){
96 setObjects();
97 ObjectContainer db = Db4o.openFile(Util.YAPFILENAME);
98 try {
99 ObjectSet pilots = db.query(Pilot.class);
100 Pilot pilot = (Pilot)pilots.get(0);
101 db.ext().purge(pilot);
102 db.set(pilot);
103 pilots = db.query(Pilot.class);
104 listResult(pilots);
105 } finally {
106 db.close();
107 }
108 }
109
111 public static void testBind(){
112 setObjects();
113 ObjectContainer db = Db4o.openFile(Util.YAPFILENAME);
114 try {
115 Query q = db.query();
116 q.constrain(Car.class);
117 q.descend("model").constrain("Ferrari");
118 ObjectSet result = q.execute();
119 Car car1 = (Car)result.get(0);
120 long IdCar1 = db.ext().getID(car1);
121 Car car2 = new Car("BMW", new Pilot("Rubens Barrichello"));
122 db.ext().bind(car2,IdCar1);
123 db.set(car2);
124
125 result = db.query(Car.class);
126 listResult(result);
127 } finally {
128 db.close();
129 }
130 }
131
133 public static void listResult(ObjectSet result) {
134 System.out.println(result.size());
135 while(result.hasNext()) {
136 System.out.println(result.next());
137 }
138 }
139 }
141 |
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