com.viaoa.hub.HubSample Maven / Gradle / Ivy

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package com.viaoa.hub;

/**
 * This will populate a Hub with the top N objects in another Hub.
 * @author vvia
 *
 */
public class HubSample {
    protected final Hub hubMaster;
    protected final Hub hubSample;
    protected final int amtSample;
    protected HubListener hubListener;

    /**
     * Create a hubSample instance.
     * @param hubMaster
     * @param hubSample will always be populated with hubMaster<0> .. 
     * @param sampleAmount number of objects in hubMaster to have in hubSample
     */
    public HubSample(Hub hubMaster, Hub hubSample, int sampleAmount) {
        this.hubMaster = hubMaster;
        this.hubSample = hubSample;
        this.amtSample = sampleAmount;
        setup();
    }
    
    protected void setup() {
        if (hubMaster == null && hubSample == null) return;
        hubListener = new HubListenerAdapter() {
            @Override
            public void afterAdd(HubEvent e) {
                int pos = hubMaster.getPos();
                if (e.getPos() < amtSample) refresh();
            }
            @Override
            public void afterInsert(HubEvent e) {
                if (e.getPos() < amtSample) refresh();
            }
            @Override
            public void afterNewList(HubEvent e) {
                refresh();
            }
            @Override
            public void afterRemove(HubEvent e) {
                if (e.getPos() < amtSample) refresh();
            }
            @Override
            public void afterRemoveAll(HubEvent e) {
                refresh();
            }
            @Override
            public void afterSort(HubEvent e) {
                refresh();
            }
        };
        hubMaster.addHubListener(hubListener);
        refresh();
    }
    
    protected void refresh() {
        for (int i=0; i amtSample) ; ) {
            hubSample.remove(amtSample);
        }
    }
    
    public void close() {
        if (hubListener != null) {
            hubMaster.removeListener(hubListener);
            hubListener = null;
        }
    }
    
    @Override
    protected void finalize() throws Throwable {
        close();
        super.finalize();
    }
    
}