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| 1 | /* | ||
| 2 | * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package java.nio.file; | ||
| 27 | |||
| 28 | import java.nio.file.attribute.*; | ||
| 29 | import java.io.IOException; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * Storage for files. A {@code FileStore} represents a storage pool, device, | ||
| 33 | * partition, volume, concrete file system or other implementation specific means | ||
| 34 | * of file storage. The {@code FileStore} for where a file is stored is obtained | ||
| 35 | * by invoking the {@link Files#getFileStore getFileStore} method, or all file | ||
| 36 | * stores can be enumerated by invoking the {@link FileSystem#getFileStores | ||
| 37 | * getFileStores} method. | ||
| 38 | * | ||
| 39 | * <p> In addition to the methods defined by this class, a file store may support | ||
| 40 | * one or more {@link FileStoreAttributeView FileStoreAttributeView} classes | ||
| 41 | * that provide a read-only or updatable view of a set of file store attributes. | ||
| 42 | * | ||
| 43 | * @since 1.7 | ||
| 44 | */ | ||
| 45 | |||
| 46 | public abstract class FileStore { | ||
| 47 | |||
| 48 | /** | ||
| 49 | * Initializes a new instance of this class. | ||
| 50 | */ | ||
| 51 | protected FileStore() { | ||
| 52 | } | ||
| 53 | |||
| 54 | /** | ||
| 55 | * Returns the name of this file store. The format of the name is highly | ||
| 56 | * implementation specific. It will typically be the name of the storage | ||
| 57 | * pool or volume. | ||
| 58 | * | ||
| 59 | * <p> The string returned by this method may differ from the string | ||
| 60 | * returned by the {@link Object#toString() toString} method. | ||
| 61 | * | ||
| 62 | * @return the name of this file store | ||
| 63 | */ | ||
| 64 | public abstract String name(); | ||
| 65 | |||
| 66 | /** | ||
| 67 | * Returns the <em>type</em> of this file store. The format of the string | ||
| 68 | * returned by this method is highly implementation specific. It may | ||
| 69 | * indicate, for example, the format used or if the file store is local | ||
| 70 | * or remote. | ||
| 71 | * | ||
| 72 | * @return a string representing the type of this file store | ||
| 73 | */ | ||
| 74 | public abstract String type(); | ||
| 75 | |||
| 76 | /** | ||
| 77 | * Tells whether this file store is read-only. A file store is read-only if | ||
| 78 | * it does not support write operations or other changes to files. Any | ||
| 79 | * attempt to create a file, open an existing file for writing etc. causes | ||
| 80 | * an {@code IOException} to be thrown. | ||
| 81 | * | ||
| 82 | * @return {@code true} if, and only if, this file store is read-only | ||
| 83 | */ | ||
| 84 | public abstract boolean isReadOnly(); | ||
| 85 | |||
| 86 | /** | ||
| 87 | * Returns the size, in bytes, of the file store. | ||
| 88 | * | ||
| 89 | * @return the size of the file store, in bytes | ||
| 90 | * | ||
| 91 | * @throws IOException | ||
| 92 | * if an I/O error occurs | ||
| 93 | */ | ||
| 94 | public abstract long getTotalSpace() throws IOException; | ||
| 95 | |||
| 96 | /** | ||
| 97 | * Returns the number of bytes available to this Java virtual machine on the | ||
| 98 | * file store. | ||
| 99 | * | ||
| 100 | * <p> The returned number of available bytes is a hint, but not a | ||
| 101 | * guarantee, that it is possible to use most or any of these bytes. The | ||
| 102 | * number of usable bytes is most likely to be accurate immediately | ||
| 103 | * after the space attributes are obtained. It is likely to be made inaccurate | ||
| 104 | * by any external I/O operations including those made on the system outside | ||
| 105 | * of this Java virtual machine. | ||
| 106 | * | ||
| 107 | * @return the number of bytes available | ||
| 108 | * | ||
| 109 | * @throws IOException | ||
| 110 | * if an I/O error occurs | ||
| 111 | */ | ||
| 112 | public abstract long getUsableSpace() throws IOException; | ||
| 113 | |||
| 114 | /** | ||
| 115 | * Returns the number of unallocated bytes in the file store. | ||
| 116 | * | ||
| 117 | * <p> The returned number of unallocated bytes is a hint, but not a | ||
| 118 | * guarantee, that it is possible to use most or any of these bytes. The | ||
| 119 | * number of unallocated bytes is most likely to be accurate immediately | ||
| 120 | * after the space attributes are obtained. It is likely to be | ||
| 121 | * made inaccurate by any external I/O operations including those made on | ||
| 122 | * the system outside of this virtual machine. | ||
| 123 | * | ||
| 124 | * @return the number of unallocated bytes | ||
| 125 | * | ||
| 126 | * @throws IOException | ||
| 127 | * if an I/O error occurs | ||
| 128 | */ | ||
| 129 | public abstract long getUnallocatedSpace() throws IOException; | ||
| 130 | |||
| 131 | /** | ||
| 132 | * Tells whether or not this file store supports the file attributes | ||
| 133 | * identified by the given file attribute view. | ||
| 134 | * | ||
| 135 | * <p> Invoking this method to test if the file store supports {@link | ||
| 136 | * BasicFileAttributeView} will always return {@code true}. In the case of | ||
| 137 | * the default provider, this method cannot guarantee to give the correct | ||
| 138 | * result when the file store is not a local storage device. The reasons for | ||
| 139 | * this are implementation specific and therefore unspecified. | ||
| 140 | * | ||
| 141 | * @param type | ||
| 142 | * the file attribute view type | ||
| 143 | * | ||
| 144 | * @return {@code true} if, and only if, the file attribute view is | ||
| 145 | * supported | ||
| 146 | */ | ||
| 147 | public abstract boolean supportsFileAttributeView(Class<? extends FileAttributeView> type); | ||
| 148 | |||
| 149 | /** | ||
| 150 | * Tells whether or not this file store supports the file attributes | ||
| 151 | * identified by the given file attribute view. | ||
| 152 | * | ||
| 153 | * <p> Invoking this method to test if the file store supports {@link | ||
| 154 | * BasicFileAttributeView}, identified by the name "{@code basic}" will | ||
| 155 | * always return {@code true}. In the case of the default provider, this | ||
| 156 | * method cannot guarantee to give the correct result when the file store is | ||
| 157 | * not a local storage device. The reasons for this are implementation | ||
| 158 | * specific and therefore unspecified. | ||
| 159 | * | ||
| 160 | * @param name | ||
| 161 | * the {@link FileAttributeView#name name} of file attribute view | ||
| 162 | * | ||
| 163 | * @return {@code true} if, and only if, the file attribute view is | ||
| 164 | * supported | ||
| 165 | */ | ||
| 166 | public abstract boolean supportsFileAttributeView(String name); | ||
| 167 | |||
| 168 | /** | ||
| 169 | * Returns a {@code FileStoreAttributeView} of the given type. | ||
| 170 | * | ||
| 171 | * <p> This method is intended to be used where the file store attribute | ||
| 172 | * view defines type-safe methods to read or update the file store attributes. | ||
| 173 | * The {@code type} parameter is the type of the attribute view required and | ||
| 174 | * the method returns an instance of that type if supported. | ||
| 175 | * | ||
| 176 | * @param type | ||
| 177 | * the {@code Class} object corresponding to the attribute view | ||
| 178 | * | ||
| 179 | * @return a file store attribute view of the specified type or | ||
| 180 | * {@code null} if the attribute view is not available | ||
| 181 | */ | ||
| 182 | public abstract <V extends FileStoreAttributeView> V | ||
| 183 | getFileStoreAttributeView(Class<V> type); | ||
| 184 | |||
| 185 | /** | ||
| 186 | * Reads the value of a file store attribute. | ||
| 187 | * | ||
| 188 | * <p> The {@code attribute} parameter identifies the attribute to be read | ||
| 189 | * and takes the form: | ||
| 190 | * <blockquote> | ||
| 191 | * <i>view-name</i><b>:</b><i>attribute-name</i> | ||
| 192 | * </blockquote> | ||
| 193 | * where the character {@code ':'} stands for itself. | ||
| 194 | * | ||
| 195 | * <p> <i>view-name</i> is the {@link FileStoreAttributeView#name name} of | ||
| 196 | * a {@link FileStore AttributeView} that identifies a set of file attributes. | ||
| 197 | * <i>attribute-name</i> is the name of the attribute. | ||
| 198 | * | ||
| 199 | * <p> <b>Usage Example:</b> | ||
| 200 | * Suppose we want to know if ZFS compression is enabled (assuming the "zfs" | ||
| 201 | * view is supported): | ||
| 202 | * <pre> | ||
| 203 | * boolean compression = (Boolean)fs.getAttribute("zfs:compression"); | ||
| 204 | * </pre> | ||
| 205 | * | ||
| 206 | * @param attribute | ||
| 207 | * the attribute to read | ||
| 208 | |||
| 209 | * @return the attribute value; {@code null} may be a valid valid for some | ||
| 210 | * attributes | ||
| 211 | * | ||
| 212 | * @throws UnsupportedOperationException | ||
| 213 | * if the attribute view is not available or it does not support | ||
| 214 | * reading the attribute | ||
| 215 | * @throws IOException | ||
| 216 | * if an I/O error occurs | ||
| 217 | */ | ||
| 218 | public abstract Object getAttribute(String attribute) throws IOException; | ||
| 219 | } | ||