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1
2
3 package com.db4odoc.f1.metainf;
4
5 import java.io.File  ;
6
7 import com.db4o.Db4o;
8 import com.db4o.ObjectContainer;
9 import com.db4o.ext.StoredClass;
10 import com.db4o.ext.StoredField;
11 import com.db4odoc.f1.Util;
12
13 public class MetaInfExample extends Util {
14
15 public static void main(String [] args) {
16 setObjects();
17 getMetaObjects();
18 getMetaObjectsInfo();
19 }
20
22 public static void setObjects(){
23 new File (Util.YAPFILENAME).delete();
24 ObjectContainer oc = Db4o.openFile(Util.YAPFILENAME);
25 try {
26 Car car = new Car("BMW", new Pilot("Rubens Barrichello"));
27 oc.set(car);
28 car = new Car("Ferrari", new Pilot("Michael Schumacher"));
29 oc.set(car);
30 } finally {
31 oc.close();
32 }
33 }
34
36 public static void getMetaObjects(){
37 ObjectContainer oc = Db4o.openFile(Util.YAPFILENAME);
38 try {
39 System.out.println("Retrieve meta information for class: ");
40 StoredClass sc = oc.ext().storedClass(Car.class.getName());
41 System.out.println("Stored class: "+ sc.toString());
42
43 System.out.println("Retrieve meta information for all classes in database: ");
44 StoredClass sclasses[] = oc.ext().storedClasses();
45 for (int i=0; i< sclasses.length; i++){
46 System.out.println(sclasses[i].getName());
47 }
48 } finally {
49 oc.close();
50 }
51 }
52
54 public static void getMetaObjectsInfo(){
55 ObjectContainer oc = Db4o.openFile(Util.YAPFILENAME);
56 try {
57 System.out.println("Retrieve meta information for field: ");
58 StoredClass sc = oc.ext().storedClass(Car.class.getName());
59 StoredField sf = sc.storedField("pilot",Pilot.class);
60 System.out.println("Field info: "+ sf.getName()+"/"+sf.getStoredType()+"/isArray="+sf.isArray());
61
62 System.out.println("Retrieve all fields: ");
63 StoredField sfields[] = sc.getStoredFields();
64 for (int i=0; i< sfields.length; i++){
65 System.out.println("Stored field: "+ sfields[i].getName()+"/"+sfields[i].getStoredType());
66 }
67 } finally {
68 oc.close();
69 }
70 }
71 }
73 |
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Java API By Example, From Geeks To Geeks.