Often applications need to present query results in a
sorted order. There are several ways to achieve this with db4o.
This Pilot class will be used in the following examples:
01/* Copyright (C) 2004 - 2006 db4objects Inc. http://www.db4o.com */ 02
03
package com.db4odoc.sorting; 04
05
public class Pilot { 06
private String name; 07
private int points; 08
09
public Pilot(String name) { 10
this.name=name; 11
} 12
13
public Pilot(String name, int points) { 14
this.name=name; 15
this.points = points; 16
} 17
18
public String getName() { 19
return name; 20
} 21
22
public int getPoints() { 23
return points; 24
} 25
26
public String toString() { 27
if (points == 0) { 28
return name; 29
} else { 30
return name + "/" + points; 31
} 32
} 33
}
The database will be filled with the following Pilot objects:
01public static void setObjects(){ 02
new File(YAPFILENAME).delete(); 03
ObjectContainer db = Db4o.openFile(YAPFILENAME); 04
try { 05
for (int i = 0; i< 10; i++){ 06
for (int j = 0; j < 5; j++){ 07
Pilot pilot = new Pilot("Pilot #"+i, j+1); 08
db.set(pilot); 09
} 10
} 11
} finally { 12
db.close(); 13
} 14
}
The following
topics discuss some of the possible methods and point out their advantages and
disadvantages.