| /* |
| * Copyright (C) 2016, 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 |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * - Neither the name of the Eclipse Foundation, Inc. nor the |
| * names of its contributors may be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
| * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package org.eclipse.jgit.internal.ketch; |
| |
| import java.io.IOException; |
| import java.util.List; |
| |
| import org.eclipse.jgit.lib.AnyObjectId; |
| import org.eclipse.jgit.transport.ReceiveCommand; |
| |
| /** |
| * One round-trip to all replicas proposing a log entry. |
| * <p> |
| * In Raft a log entry represents a state transition at a specific index in the |
| * replicated log. The leader can only append log entries to the log. |
| * <p> |
| * In Ketch a log entry is recorded under the {@code refs/txn} namespace. This |
| * occurs when: |
| * <ul> |
| * <li>a replica wants to establish itself as a new leader by proposing a new |
| * term (see {@link ElectionRound}) |
| * <li>an established leader wants to gain consensus on new {@link Proposal}s |
| * (see {@link ProposalRound}) |
| * </ul> |
| */ |
| abstract class Round { |
| final KetchLeader leader; |
| final LogIndex acceptedOldIndex; |
| LogIndex acceptedNewIndex; |
| List<ReceiveCommand> stageCommands; |
| |
| Round(KetchLeader leader, LogIndex head) { |
| this.leader = leader; |
| this.acceptedOldIndex = head; |
| } |
| |
| KetchSystem getSystem() { |
| return leader.getSystem(); |
| } |
| |
| /** |
| * Creates a commit for {@code refs/txn/accepted} and calls |
| * {@link #runAsync(AnyObjectId)} to begin execution of the round across |
| * the system. |
| * <p> |
| * If references are being updated (such as in a {@link ProposalRound}) the |
| * RefTree may be modified. |
| * <p> |
| * Invoked without {@link KetchLeader#lock} to build objects. |
| * |
| * @throws IOException |
| * the round cannot build new objects within the leader's |
| * repository. The leader may be unable to execute. |
| */ |
| abstract void start() throws IOException; |
| |
| /** |
| * Asynchronously distribute the round's new value for |
| * {@code refs/txn/accepted} to all replicas. |
| * <p> |
| * Invoked by {@link #start()} after new commits have been created for the |
| * log. The method passes {@code newId} to {@link KetchLeader} to be |
| * distributed to all known replicas. |
| * |
| * @param newId |
| * new value for {@code refs/txn/accepted}. |
| */ |
| void runAsync(AnyObjectId newId) { |
| acceptedNewIndex = acceptedOldIndex.nextIndex(newId); |
| leader.runAsync(this); |
| } |
| |
| /** |
| * Notify the round it was accepted by a majority of the system. |
| * <p> |
| * Invoked by the leader with {@link KetchLeader#lock} held by the caller. |
| */ |
| abstract void success(); |
| } |