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 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
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package org.eclipse.jgit.lib;

import java.io.IOException;

import org.eclipse.jgit.errors.MissingObjectException;

Queue to examine object sizes asynchronously.
A queue may perform background lookup of object sizes and supply them
(possibly out-of-order) to the application.
Type parameters:
<T> – 
           type of identifier supplied to the call that made the queue./**
 * Queue to examine object sizes asynchronously.
 *
 * A queue may perform background lookup of object sizes and supply them
 * (possibly out-of-order) to the application.
 *
 * @param <T>
 *            type of identifier supplied to the call that made the queue.
 */
public interface AsyncObjectSizeQueue<T extends ObjectId> extends
		AsyncOperation {

	
Position this queue onto the next available result.
Throws:
MissingObjectException –  the object does not exist. If the implementation is retaining the application's objects getCurrent() will be the current object that is missing. There may be more results still available, so the caller should continue invoking next to examine another result.
IOException – 
            the object store cannot be accessed.
Returns:
true if there is a result available; false if the queue has
        finished its input iteration./**
	 * Position this queue onto the next available result.
	 *
	 * @return true if there is a result available; false if the queue has
	 *         finished its input iteration.
	 * @throws org.eclipse.jgit.errors.MissingObjectException
	 *             the object does not exist. If the implementation is retaining
	 *             the application's objects {@link #getCurrent()} will be the
	 *             current object that is missing. There may be more results
	 *             still available, so the caller should continue invoking next
	 *             to examine another result.
	 * @throws java.io.IOException
	 *             the object store cannot be accessed.
	 */
	boolean next() throws MissingObjectException, IOException;

	
getCurrent.
Returns:
the current object, null if the implementation lost track. Implementations may for performance reasons discard the caller's ObjectId and provider their own through getObjectId()./**
	 * <p>getCurrent.</p>
	 *
	 * @return the current object, null if the implementation lost track.
	 *         Implementations may for performance reasons discard the caller's
	 *         ObjectId and provider their own through {@link #getObjectId()}.
	 */
	T getCurrent();

	
Get the ObjectId of the current object. Never null.
Returns:
the ObjectId of the current object. Never null./**
	 * Get the ObjectId of the current object. Never null.
	 *
	 * @return the ObjectId of the current object. Never null.
	 */
	ObjectId getObjectId();

	
Get the size of the current object.
Returns:
the size of the current object./**
	 * Get the size of the current object.
	 *
	 * @return the size of the current object.
	 */
	long getSize();
}