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1   /*
2    * Copyright (C) 2016 Ericsson and others
3    *
4    * This program and the accompanying materials are made available under the
5    * terms of the Eclipse Distribution License v. 1.0 which is available at
6    * https://www.eclipse.org/org/documents/edl-v10.php.
7    *
8    * SPDX-License-Identifier: BSD-3-Clause
9    */
10  package org.eclipse.jgit.lib;
11  
12  import java.util.concurrent.TimeUnit;
13  
14  /**
15   * Configuration parameters for JVM-wide repository cache used by JGit.
16   *
17   * @since 4.4
18   */
19  public class RepositoryCacheConfig {
20  
21  	/**
22  	 * Set cleanupDelayMillis to this value in order to switch off time-based
23  	 * cache eviction. Expired cache entries will only be evicted when
24  	 * RepositoryCache.clearExpired or RepositoryCache.clear are called.
25  	 */
26  	public static final long NO_CLEANUP = 0;
27  
28  	/**
29  	 * Set cleanupDelayMillis to this value in order to auto-set it to minimum
30  	 * of 1/10 of expireAfterMillis and 10 minutes
31  	 */
32  	public static final long AUTO_CLEANUP_DELAY = -1;
33  
34  	private long expireAfterMillis;
35  
36  	private long cleanupDelayMillis;
37  
38  	/**
39  	 * Create a default configuration.
40  	 */
41  	public RepositoryCacheConfig() {
42  		expireAfterMillis = TimeUnit.HOURS.toMillis(1);
43  		cleanupDelayMillis = AUTO_CLEANUP_DELAY;
44  	}
45  
46  	/**
47  	 * Get the time an unused repository should be expired and be evicted from
48  	 * the RepositoryCache in milliseconds.
49  	 *
50  	 * @return the time an unused repository should be expired and be evicted
51  	 *         from the RepositoryCache in milliseconds. <b>Default is 1
52  	 *         hour.</b>
53  	 */
54  	public long getExpireAfter() {
55  		return expireAfterMillis;
56  	}
57  
58  	/**
59  	 * Set the time an unused repository should be expired and be evicted from
60  	 * the RepositoryCache in milliseconds.
61  	 *
62  	 * @param expireAfterMillis
63  	 *            the time an unused repository should be expired and be evicted
64  	 *            from the RepositoryCache in milliseconds.
65  	 */
66  	public void setExpireAfter(long expireAfterMillis) {
67  		this.expireAfterMillis = expireAfterMillis;
68  	}
69  
70  	/**
71  	 * Get the delay between the periodic cleanup of expired repository in
72  	 * milliseconds.
73  	 *
74  	 * @return the delay between the periodic cleanup of expired repository in
75  	 *         milliseconds. <b>Default is minimum of 1/10 of expireAfterMillis
76  	 *         and 10 minutes</b>
77  	 */
78  	public long getCleanupDelay() {
79  		if (cleanupDelayMillis < 0) {
80  			return Math.min(expireAfterMillis / 10,
81  					TimeUnit.MINUTES.toMillis(10));
82  		}
83  		return cleanupDelayMillis;
84  	}
85  
86  	/**
87  	 * Set the delay between the periodic cleanup of expired repository in
88  	 * milliseconds.
89  	 *
90  	 * @param cleanupDelayMillis
91  	 *            the delay between the periodic cleanup of expired repository
92  	 *            in milliseconds. Set it to {@link #AUTO_CLEANUP_DELAY} to
93  	 *            automatically derive cleanup delay from expireAfterMillis.
94  	 *            <p>
95  	 *            Set it to {@link #NO_CLEANUP} in order to switch off cache
96  	 *            expiration.
97  	 *            <p>
98  	 *            If cache expiration is switched off the JVM still can evict
99  	 *            cache entries when the JVM is running low on available heap
100 	 *            memory.
101 	 */
102 	public void setCleanupDelay(long cleanupDelayMillis) {
103 		this.cleanupDelayMillis = cleanupDelayMillis;
104 	}
105 
106 	/**
107 	 * Update properties by setting fields from the configuration.
108 	 * <p>
109 	 * If a property is not defined in the configuration, then it is left
110 	 * unmodified.
111 	 *
112 	 * @param config
113 	 *            configuration to read properties from.
114 	 * @return {@code this}.
115 	 */
116 	public RepositoryCacheConfig fromConfig(Config config) {
117 		setExpireAfter(
118 				config.getTimeUnit("core", null, "repositoryCacheExpireAfter", //$NON-NLS-1$//$NON-NLS-2$
119 						getExpireAfter(), TimeUnit.MILLISECONDS));
120 		setCleanupDelay(
121 				config.getTimeUnit("core", null, "repositoryCacheCleanupDelay", //$NON-NLS-1$ //$NON-NLS-2$
122 						AUTO_CLEANUP_DELAY, TimeUnit.MILLISECONDS));
123 		return this;
124 	}
125 
126 	/**
127 	 * Install this configuration as the live settings.
128 	 * <p>
129 	 * The new configuration is applied immediately.
130 	 */
131 	public void install() {
132 		RepositoryCache.reconfigure(this);
133 	}
134 }