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 - 2007 db4objects Inc. http://www.db4o.com */ 02
03
package com.db4odoc.sorting; 04
05
public class Pilot { 06
private String name; 07
08
private int points; 09
10
public Pilot(String name) { 11
this.name = name; 12
} 13
14
public Pilot(String name, int points) { 15
this.name = name; 16
this.points = points; 17
} 18
19
public String getName() { 20
return name; 21
} 22
23
public int getPoints() { 24
return points; 25
} 26
27
public String toString() { 28
if (points == 0) { 29
return name; 30
} else { 31
return name + "/" + points; 32
} 33
} 34
}
The database will be filled with the following Pilot objects:
01public static void setObjects() { 02
new File(DB4O_FILE_NAME).delete(); 03
ObjectContainer container = Db4o.openFile(DB4O_FILE_NAME); 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
container.set(pilot); 09
} 10
} 11
} finally { 12
container.close(); 13
} 14
}
The following
topics discuss some of the possible methods and point out their advantages and
disadvantages.