|
1 package com.db4o.f1.chapter3;
2
3 import java.io.*;
4 import java.util.*;
5 import com.db4o.*;
6 import com.db4o.f1.*;
7 import com.db4o.query.*;
8
9
10 public class CollectionsExample 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 storeFirstCar(db);
16 storeSecondCar(db);
17 retrieveAllSensorReadout(db);
18 retrieveSensorReadoutQBE(db);
19 retrieveCarQBE(db);
20 retrieveCollections(db);
21 retrieveArrays(db);
22 retrieveAllSensorReadoutNative(db);
23 retrieveSensorReadoutNative(db);
24 retrieveCarNative(db);
25 retrieveSensorReadoutQuery(db);
26 retrieveCarQuery(db);
27 db.close();
28 updateCarPart1();
29 db=Db4o.openFile(Util.YAPFILENAME);
30 updateCarPart2(db);
31 updateCollection(db);
32 db.close();
33 deleteAllPart1();
34 db=Db4o.openFile(Util.YAPFILENAME);
35 deleteAllPart2(db);
36 }
37 finally {
38 db.close();
39 }
40 }
41
42 public static void storeFirstCar(ObjectContainer db) {
43 Car car1=new Car("Ferrari");
44 Pilot pilot1=new Pilot("Michael Schumacher",100);
45 car1.setPilot(pilot1);
46 db.set(car1);
47 }
48
49 public static void storeSecondCar(ObjectContainer db) {
50 Pilot pilot2=new Pilot("Rubens Barrichello",99);
51 Car car2=new Car("BMW");
52 car2.setPilot(pilot2);
53 car2.snapshot();
54 car2.snapshot();
55 db.set(car2);
56 }
57
58 public static void retrieveAllSensorReadout(
59 ObjectContainer db) {
60 SensorReadout proto=new SensorReadout(null,null,null);
61 ObjectSet results=db.get(proto);
62 listResult(results);
63 }
64
65 public static void retrieveAllSensorReadoutNative(
66 ObjectContainer db) {
67 ObjectSet results = db.query(new Predicate() {
68 public boolean match(SensorReadout candidate){
69 return true;
70 }
71 });
72 listResult(results);
73 }
74
75 public static void retrieveSensorReadoutQBE(
76 ObjectContainer db) {
77 SensorReadout proto=new SensorReadout(
78 new double[]{0.3,0.1},null,null);
79 ObjectSet results=db.get(proto);
80 listResult(results);
81 }
82
83 public static void retrieveSensorReadoutNative(
84 ObjectContainer db) {
85 ObjectSet results = db.query(new Predicate() {
86 public boolean match(SensorReadout candidate){
87 return Arrays.binarySearch(candidate.getValues(), 0.3) >= 0
88 && Arrays.binarySearch(candidate.getValues(), 1.0) >= 0;
89 }
90 });
91 listResult(results);
92 }
93
94 public static void retrieveCarQBE(ObjectContainer db) {
95 SensorReadout protoreadout=new SensorReadout(
96 new double[]{0.6,0.2},null,null);
97 List protohistory=new ArrayList();
98 protohistory.add(protoreadout);
99 Car protocar=new Car(null,protohistory);
100 ObjectSet result=db.get(protocar);
101 listResult(result);
102 }
103
104 public static void retrieveCarNative(
105 ObjectContainer db) {
106 ObjectSet results = db.query(new Predicate() {
107 public boolean match(Car candidate){
108 List history = candidate.getHistory();
109 for(int i = 0; i < history.size(); i++){
110 SensorReadout readout = (SensorReadout)history.get(i);
111 if( Arrays.binarySearch(readout.getValues(), 0.6) >= 0 ||
112 Arrays.binarySearch(readout.getValues(), 0.2) >= 0)
113 return true;
114 }
115 return false;
116 }
117 });
118 listResult(results);
119 }
120
121 public static void retrieveCollections(ObjectContainer db) {
122 ObjectSet result=db.get(new ArrayList());
123 listResult(result);
124 }
125
126 public static void retrieveArrays(ObjectContainer db) {
127 ObjectSet result=db.get(new double[]{0.6,0.4});
128 listResult(result);
129 }
130
131 public static void retrieveSensorReadoutQuery(
132 ObjectContainer db) {
133 Query query=db.query();
134 query.constrain(SensorReadout.class);
135 Query valuequery=query.descend("values");
136 valuequery.constrain(new Double (0.3));
137 valuequery.constrain(new Double (0.1));
138 ObjectSet result=query.execute();
139 listResult(result);
140 }
141
142 public static void retrieveCarQuery(ObjectContainer db) {
143 Query query=db.query();
144 query.constrain(Car.class);
145 Query historyquery=query.descend("history");
146 historyquery.constrain(SensorReadout.class);
147 Query valuequery=historyquery.descend("values");
148 valuequery.constrain(new Double (0.3));
149 valuequery.constrain(new Double (0.1));
150 ObjectSet result=query.execute();
151 listResult(result);
152 }
153
154 public static void updateCarPart1() {
155 Db4o.configure().objectClass(Car.class).cascadeOnUpdate(true);
156 }
157
158 public static void updateCarPart2(ObjectContainer db) {
159 ObjectSet results = db.query(new Predicate() {
160 public boolean match(Car candidate){
161 return true;
162 }
163 });
164 Car car=(Car)results.next();
165 car.snapshot();
166 db.set(car);
167 retrieveAllSensorReadoutNative(db);
168 }
169
170 public static void updateCollection(ObjectContainer db) {
171 ObjectSet results = db.query(new Predicate() {
172 public boolean match(Car candidate){
173 return true;
174 }
175 });
176 Car car =(Car)results.next();
177 car.getHistory().remove(0);
178 db.set(car.getHistory());
179 results = db.query(new Predicate() {
180 public boolean match(Car candidate){
181 return true;
182 }
183 });
184 while(results.hasNext()) {
185 car=(Car)results.next();
186 for (int idx=0;idx<car.getHistory().size();idx++) {
187 System.out.println(car.getHistory().get(idx));
188 }
189 }
190 }
191
192 public static void deleteAllPart1() {
193 Db4o.configure().objectClass(Car.class)
194 .cascadeOnDelete(true);
195 }
196
197 public static void deleteAllPart2(ObjectContainer db) {
198 ObjectSet cars = db.query(new Predicate() {
199 public boolean match(Car candidate){
200 return true;
201 }
202 });
203 while(cars.hasNext()) {
204 db.delete(cars.next());
205 }
206 ObjectSet readouts = db.query(new Predicate() {
207 public boolean match(SensorReadout candidate){
208 return true;
209 }
210 });
211 while(readouts.hasNext()) {
212 db.delete(readouts.next());
213 }
214 }
215 }
216 |
Popular Tags |
Java API By Example, From Geeks To Geeks.