class AbstractTrack implements Track {
    String name;
    List<Edit> edits = new ArrayList<Edit>();
    Map<GroupEntry, long[]> sampleGroups = new HashMap<GroupEntry, long[]>();

    public AbstractTrack(String name) {
        this.name = name;
    }

    public List<CompositionTimeToSample.Entry> getCompositionTimeEntries() {
        return null;
    }

    public long[] getSyncSamples() {
        return null;
    }

    public List<SampleDependencyTypeBox.Entry> getSampleDependencies() {
        return null;
    }

    public SubSampleInformationBox getSubsampleInformationBox() {
        return null;
    }

    public long getDuration() {<FILL_FUNCTION_BODY>}

    public String getName() {
        return this.name;
    }

    public List<Edit> getEdits() {
        return edits;
    }

    public Map<GroupEntry, long[]> getSampleGroups() {
        return sampleGroups;
    }
}

        long duration = 0;
        for (long delta : getSampleDurations()) {
            duration += delta;
        }
        return duration;
    
<no_super_class>