Java tutorial
/* * 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 * * 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.storage.dfs; import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_CORE_SECTION; import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_DFS_SECTION; import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_DELTA_BASE_CACHE_LIMIT; import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_STREAM_BUFFER; import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_STREAM_FILE_TRESHOLD; import org.eclipse.jgit.lib.Config; import org.eclipse.jgit.storage.pack.PackConfig; /** * Options controlling how objects are read from a DFS stored repository. */ public class DfsReaderOptions { /** 1024 (number of bytes in one kibibyte/kilobyte) */ public static final int KiB = 1024; /** 1024 {@link #KiB} (number of bytes in one mebibyte/megabyte) */ public static final int MiB = 1024 * KiB; private int deltaBaseCacheLimit; private int streamFileThreshold; private int streamPackBufferSize; /** * Create a default reader configuration. */ public DfsReaderOptions() { setDeltaBaseCacheLimit(10 * MiB); setStreamFileThreshold(PackConfig.DEFAULT_BIG_FILE_THRESHOLD); } /** * Get maximum number of bytes to hold in per-reader DeltaBaseCache. * * @return maximum number of bytes to hold in per-reader DeltaBaseCache. */ public int getDeltaBaseCacheLimit() { return deltaBaseCacheLimit; } /** * Set the maximum number of bytes in the DeltaBaseCache. * * @param maxBytes * the new limit. * @return {@code this} */ public DfsReaderOptions setDeltaBaseCacheLimit(int maxBytes) { deltaBaseCacheLimit = Math.max(0, maxBytes); return this; } /** * 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}. * @return {@code this} */ public DfsReaderOptions setStreamFileThreshold(int newLimit) { streamFileThreshold = Math.max(0, newLimit); return this; } /** * Get number of bytes to use for buffering when streaming a pack file * during copying. * * @return number of bytes to use for buffering when streaming a pack file * during copying. If 0 the block size of the pack is used. */ public int getStreamPackBufferSize() { return streamPackBufferSize; } /** * Set new buffer size in bytes for buffers used when streaming pack files * during copying. * * @param bufsz * new buffer size in bytes for buffers used when streaming pack * files during copying. * @return {@code this} */ public DfsReaderOptions setStreamPackBufferSize(int bufsz) { streamPackBufferSize = Math.max(0, bufsz); return this; } /** * 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} */ public DfsReaderOptions fromConfig(Config rc) { setDeltaBaseCacheLimit(rc.getInt(CONFIG_CORE_SECTION, CONFIG_DFS_SECTION, CONFIG_KEY_DELTA_BASE_CACHE_LIMIT, getDeltaBaseCacheLimit())); long maxMem = Runtime.getRuntime().maxMemory(); long sft = rc.getLong(CONFIG_CORE_SECTION, CONFIG_DFS_SECTION, CONFIG_KEY_STREAM_FILE_TRESHOLD, getStreamFileThreshold()); 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); setStreamPackBufferSize(rc.getInt(CONFIG_CORE_SECTION, CONFIG_DFS_SECTION, CONFIG_KEY_STREAM_BUFFER, getStreamPackBufferSize())); return this; } }