| /* |
| * Copyright (C) 2016, Google Inc. and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.internal.ketch; |
| |
| import java.net.URISyntaxException; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| import org.eclipse.jgit.internal.storage.dfs.DfsRepository; |
| import org.eclipse.jgit.lib.Repository; |
| |
| /** |
| * A cache of live leader instances, keyed by repository. |
| * <p> |
| * Ketch only assigns a leader to a repository when needed. If |
| * {@link #get(Repository)} is called for a repository that does not have a |
| * leader, the leader is created and added to the cache. |
| */ |
| public class KetchLeaderCache { |
| private final KetchSystem system; |
| private final ConcurrentMap<String, KetchLeader> leaders; |
| private final Lock startLock; |
| |
| /** |
| * Initialize a new leader cache. |
| * |
| * @param system |
| * system configuration for the leaders |
| */ |
| public KetchLeaderCache(KetchSystem system) { |
| this.system = system; |
| leaders = new ConcurrentHashMap<>(); |
| startLock = new ReentrantLock(true /* fair */); |
| } |
| |
| /** |
| * Lookup the leader instance for a given repository. |
| * |
| * @param repo |
| * repository to get the leader for. |
| * @return the leader instance for the repository. |
| * @throws java.net.URISyntaxException |
| * remote configuration contains an invalid URL. |
| */ |
| public KetchLeader get(Repository repo) |
| throws URISyntaxException { |
| String key = computeKey(repo); |
| KetchLeader leader = leaders.get(key); |
| if (leader != null) { |
| return leader; |
| } |
| return startLeader(key, repo); |
| } |
| |
| private KetchLeader startLeader(String key, Repository repo) |
| throws URISyntaxException { |
| startLock.lock(); |
| try { |
| KetchLeader leader = leaders.get(key); |
| if (leader != null) { |
| return leader; |
| } |
| leader = system.createLeader(repo); |
| leaders.put(key, leader); |
| return leader; |
| } finally { |
| startLock.unlock(); |
| } |
| } |
| |
| private static String computeKey(Repository repo) { |
| if (repo instanceof DfsRepository) { |
| DfsRepository dfs = (DfsRepository) repo; |
| return dfs.getDescription().getRepositoryName(); |
| } |
| |
| if (repo.getDirectory() != null) { |
| return repo.getDirectory().toURI().toString(); |
| } |
| |
| throw new IllegalArgumentException(); |
| } |
| } |