org.jvnet.hk2.component.InhabitantTracker Maven / Gradle / Ivy
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package org.jvnet.hk2.component;
import java.util.Collection;
/**
* Tracks an inhabitant, or set of inhabitants.
*
* @see Habitat#track(InhabitantTrackerContext, Callback)
* @see Habitat#trackFuture(InhabitantTrackerContext, Boolean)
*
* @author Jeff Trent
*
* @since 3.1
*/
public interface InhabitantTracker {
/**
* Returns a single inhabitant. If multiple inhabitants qualify,
* the one selected is based upon the implementation.
*
* @return an inhabitant, or null if no inhabitants match tracker criteria
*/
public Inhabitant getInhabitant() throws ComponentException;
/**
* Returns the set of inhabitants qualifying.
*
* @return the collection of inhabitants matching tracker criteria
*/
public Collection> getInhabitants() throws ComponentException;
/**
* Releases / closes this tracker. This MUST be called for performance reasons,
* to cleanup resources.
*/
public void release();
/**
* The callback is called when there is an event changing one of the tracked
* inhabitants. The callback may occur on a different thread than the one
* that originated the change in the habitat.
*/
public static interface Callback {
/**
* Called when there is a modification to the set of inhabitants of some kind.
*
* @param t the tracker
* @param h the habitat
* @param initial
* true if the updated even happens during initial tracker creation taking
* inventory of starting matches
*/
public void updated(InhabitantTracker t, Habitat h, boolean initial);
}
}