Java tutorial
/* * Copyright (C) 2009, 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.storage.file; import org.eclipse.jgit.internal.storage.file.WindowCache; import org.eclipse.jgit.lib.Config; import org.eclipse.jgit.storage.pack.PackConfig; /** * Configuration parameters for JVM-wide buffer cache used by JGit. */ public class WindowCacheConfig { /** 1024 (number of bytes in one kibibyte/kilobyte) */ public static final int KB = 1024; /** 1024 {@link #KB} (number of bytes in one mebibyte/megabyte) */ public static final int MB = 1024 * KB; private int packedGitOpenFiles; private long packedGitLimit; private int packedGitWindowSize; private boolean packedGitMMAP; private int deltaBaseCacheLimit; private int streamFileThreshold; /** * Create a default configuration. */ public WindowCacheConfig() { packedGitOpenFiles = 128; packedGitLimit = 10 * MB; packedGitWindowSize = 8 * KB; packedGitMMAP = false; deltaBaseCacheLimit = 10 * MB; streamFileThreshold = PackConfig.DEFAULT_BIG_FILE_THRESHOLD; } /** * Get maximum number of streams to open at a time. * * @return maximum number of streams to open at a time. Open packs count * against the process limits. <b>Default is 128.</b> */ public int getPackedGitOpenFiles() { return packedGitOpenFiles; } /** * Set maximum number of streams to open at a time. * * @param fdLimit * maximum number of streams to open at a time. Open packs count * against the process limits */ public void setPackedGitOpenFiles(int fdLimit) { packedGitOpenFiles = fdLimit; } /** * Get maximum number bytes of heap memory to dedicate to caching pack file * data. * * @return maximum number bytes of heap memory to dedicate to caching pack * file data. <b>Default is 10 MB.</b> */ public long getPackedGitLimit() { return packedGitLimit; } /** * Set maximum number bytes of heap memory to dedicate to caching pack file * data. * * @param newLimit * maximum number bytes of heap memory to dedicate to caching * pack file data. */ public void setPackedGitLimit(long newLimit) { packedGitLimit = newLimit; } /** * Get size in bytes of a single window mapped or read in from the pack * file. * * @return size in bytes of a single window mapped or read in from the pack * file. <b>Default is 8 KB.</b> */ public int getPackedGitWindowSize() { return packedGitWindowSize; } /** * Set size in bytes of a single window read in from the pack file. * * @param newSize * size in bytes of a single window read in from the pack file. */ public void setPackedGitWindowSize(int newSize) { packedGitWindowSize = newSize; } /** * Whether to use Java NIO virtual memory mapping for windows * * @return {@code true} enables use of Java NIO virtual memory mapping for * windows; false reads entire window into a byte[] with standard * read calls. <b>Default false.</b> */ public boolean isPackedGitMMAP() { return packedGitMMAP; } /** * Set whether to enable use of Java NIO virtual memory mapping for windows * * @param usemmap * {@code true} enables use of Java NIO virtual memory mapping * for windows; false reads entire window into a byte[] with * standard read calls. */ public void setPackedGitMMAP(boolean usemmap) { packedGitMMAP = usemmap; } /** * Get maximum number of bytes to cache in delta base cache for inflated, * recently accessed objects, without delta chains. * * @return maximum number of bytes to cache in delta base cache for * inflated, recently accessed objects, without delta chains. * <b>Default 10 MB.</b> */ public int getDeltaBaseCacheLimit() { return deltaBaseCacheLimit; } /** * Set maximum number of bytes to cache in delta base cache for inflated, * recently accessed objects, without delta chains. * * @param newLimit * maximum number of bytes to cache in delta base cache for * inflated, recently accessed objects, without delta chains. */ public void setDeltaBaseCacheLimit(int newLimit) { deltaBaseCacheLimit = newLimit; } /** * Get the size threshold beyond which objects must be streamed. * * @return the size threshold beyond which objects must be streamed. */ public int getStreamFileThreshold() { return streamFileThreshold; } /** * Set new byte limit for objects that must be streamed. * * @param newLimit * new byte limit for objects that must be streamed. Objects * smaller than this size can be obtained as a contiguous byte * array, while objects bigger than this size require using an * {@link org.eclipse.jgit.lib.ObjectStream}. */ public void setStreamFileThreshold(int newLimit) { streamFileThreshold = newLimit; } /** * Update properties by setting fields from the configuration. * <p> * If a property is not defined in the configuration, then it is left * unmodified. * * @param rc * configuration to read properties from. * @return {@code this}. * @since 3.0 */ public WindowCacheConfig fromConfig(Config rc) { setPackedGitOpenFiles(rc.getInt("core", null, "packedgitopenfiles", getPackedGitOpenFiles())); //$NON-NLS-1$ //$NON-NLS-2$ setPackedGitLimit(rc.getLong("core", null, "packedgitlimit", getPackedGitLimit())); //$NON-NLS-1$ //$NON-NLS-2$ setPackedGitWindowSize(rc.getInt("core", null, "packedgitwindowsize", getPackedGitWindowSize())); //$NON-NLS-1$ //$NON-NLS-2$ setPackedGitMMAP(rc.getBoolean("core", null, "packedgitmmap", isPackedGitMMAP())); //$NON-NLS-1$ //$NON-NLS-2$ setDeltaBaseCacheLimit(rc.getInt("core", null, "deltabasecachelimit", getDeltaBaseCacheLimit())); //$NON-NLS-1$ //$NON-NLS-2$ long maxMem = Runtime.getRuntime().maxMemory(); long sft = rc.getLong("core", null, "streamfilethreshold", getStreamFileThreshold()); //$NON-NLS-1$ //$NON-NLS-2$ sft = Math.min(sft, maxMem / 4); // don't use more than 1/4 of the heap sft = Math.min(sft, Integer.MAX_VALUE); // cannot exceed array length setStreamFileThreshold((int) sft); return this; } /** * Install this configuration as the live settings. * <p> * The new configuration is applied immediately. If the new limits are * smaller than what is currently cached, older entries will be purged * as soon as possible to allow the cache to meet the new limit. * * @since 3.0 */ @SuppressWarnings("deprecation") public void install() { WindowCache.reconfigure(this); } }