Inheritance in Spring - spring

Question

I have parent class with a long variable. I do an initialization in the init() method (#PostConstruct) and want to pass a new value into the sub-class. How to do this in Spring?
Here is a snippet of my code:
#Component
public class Track implements Serializable {
protected long trackId;
#PostConstruct
public void init() {
this.trackId = sequencesDao.getNext("TRACK_SEQ");
}
}
#Component("trackPoint")
#Scope("prototype")
public class TrackPoint extends Track implements Serializable, Cloneable {
...
}
somewhere in the code:
Track trk = context.getBean("track", Track.class);
...
TrackPoint trkpt = (TrackPoint)context.getBean("trackPoint",
new Object[]{new Double(eElement.getAttributes().item(0).getNodeValue()),
new Double(eElement.getAttributes().item(1).getNodeValue()),
0.0,
date});
In the debug I see the trackId = 0, but it has to be initialized by sequence value. In other words, trackId <> 0 after the initialization of Track, but it =0 after the initialization of TrackPoint. What is missing?
P.S. Spring 3.2.10.RELEASE

Answer 1

I created something similar as you have and I have no problem...
Track
package betlista.tests.so.spring;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;
public class Track {
#Resource
SequencesDao sequencesDao;
protected long trackId;
#PostConstruct
public void init() {
this.trackId = sequencesDao.getNext("TRACK_SEQ");
}
#Override
public String toString() {
return "Track(" + hashCode() + "): " + trackId;
}
}
TrackPoint
package betlista.tests.so.spring;
public class TrackPoint extends Track {
#Override
public String toString() {
return "TrackPoint(" + hashCode() + "): " + trackId;
}
}
JavaConfig
package betlista.tests.so.spring;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;
#Configuration
public class JavaConfig {
#Bean()
public SequencesDao getSequencesDao() {
return new SequencesDao();
}
#Bean(name="track")
public Track getTrack() {
return new Track();
}
#Bean(name="trackPoint")
#Scope("prototype")
public TrackPoint getTrackPoint() {
return new TrackPoint();
}
}
SequencesDao
package betlista.tests.so.spring;
public class SequencesDao {
int cur = 0;
public int getNext(String s) {
return cur++;
}
}
Runner
package betlista.tests.so.spring;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class Runner {
public static void main(String[] args) {
ApplicationContext ctx =
new AnnotationConfigApplicationContext(JavaConfig.class);
Track track1 = ctx.getBean("track", Track.class);
System.out.println(track1);
Track track2 = ctx.getBean("track", Track.class);
System.out.println(track2);
System.out.println(track1 == track2);
TrackPoint trackPoint1 = ctx.getBean(TrackPoint.class);
System.out.println(trackPoint1);
TrackPoint trackPoint2 = ctx.getBean(TrackPoint.class);
System.out.println(trackPoint2);
System.out.println(trackPoint1 == trackPoint2);
}
}
and the output from Runner is as expected
Track(1542629621): 0
Track(1542629621): 0
true
TrackPoint(991593213): 1
TrackPoint(1234030171): 2
false
just for completeness, my pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>betlista-tests</groupId>
<artifactId>so-spring-inheritance</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>3.2.10.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.2.10.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>jsr250-api</artifactId>
<version>1.0</version>
</dependency>
</dependencies>
</project>
So I still see only two options, you DAO is not working well, or TrackPoint is, because of some reason, singleton...
Add similar logging to you code as I have to compare...

Answer 2

The problem is resolved - I've made trackId static and TrackPoint keeps it initialized.