org.eclipse.jgit.storage.dht/src/org/eclipse/jgit/storage/dht/spi/WriteBuffer.java

/*
 * Copyright (C) 2011, Google Inc.
 * and other copyright owners as documented in the project's IP log.
 *
 * 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
 * available at http://www.eclipse.org/org/documents/edl-v10.php
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package org.eclipse.jgit.storage.dht.spi;

import org.eclipse.jgit.storage.dht.DhtException;

/** Potentially buffers writes until full, or until flush. */
public interface WriteBuffer {
	/**
	 * Flush any pending writes, and wait for them to complete.
	 *
	 * @throws DhtException
	 *             one or more writes failed. As writes may occur in any order,
	 *             the exact state of the database is unspecified.
	 */
	public void flush() throws DhtException;

	/**
	 * Abort pending writes, and wait for acknowledgment.
	 * <p>
	 * Once a buffer has been aborted, it cannot be reused. Application code
	 * must discard the buffer instance and use a different buffer to issue
	 * subsequent operations.
	 * <p>
	 * If writes have not been started yet, they should be discarded and not
	 * submitted to the storage system.
	 * <p>
	 * If writes have already been started asynchronously in the background,
	 * this method may try to cancel them, but must wait for the operation to
	 * either complete or abort before returning. This allows callers to clean
	 * up by scanning the storage system and making corrections to clean up any
	 * partial writes.
	 *
	 * @throws DhtException
	 *             one or more already started writes failed.
	 */
	public void abort() throws DhtException;
}