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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.spi.FileSystemProvider; | |
| 29 | +import java.net.URI; | |
| 30 | + | |
| 31 | +/** | |
| 32 | + * This class consists exclusively of static methods that return a {@link Path} | |
| 33 | + * by converting a path string or {@link URI}. | |
| 34 | + * | |
| 35 | + * @since 1.7 | |
| 36 | + */ | |
| 37 | + | |
| 38 | +public final class Paths { | |
| 39 | + private Paths() { } | |
| 40 | + | |
| 41 | + /** | |
| 42 | + * Converts a path string, or a sequence of strings that when joined form | |
| 43 | + * a path string, to a {@code Path}. If {@code more} does not specify any | |
| 44 | + * elements then the value of the {@code first} parameter is the path string | |
| 45 | + * to convert. If {@code more} specifies one or more elements then each | |
| 46 | + * non-empty string, including {@code first}, is considered to be a sequence | |
| 47 | + * of name elements (see {@link Path}) and is joined to form a path string. | |
| 48 | + * The details as to how the Strings are joined is provider specific but | |
| 49 | + * typically they will be joined using the {@link FileSystem#getSeparator | |
| 50 | + * name-separator} as the separator. For example, if the name separator is | |
| 51 | + * "{@code /}" and {@code getPath("/foo","bar","gus")} is invoked, then the | |
| 52 | + * path string {@code "/foo/bar/gus"} is converted to a {@code Path}. | |
| 53 | + * A {@code Path} representing an empty path is returned if {@code first} | |
| 54 | + * is the empty string and {@code more} does not contain any non-empty | |
| 55 | + * strings. | |
| 56 | + * | |
| 57 | + * <p> The {@code Path} is obtained by invoking the {@link FileSystem#getPath | |
| 58 | + * getPath} method of the {@link FileSystems#getDefault default} {@link | |
| 59 | + * FileSystem}. | |
| 60 | + * | |
| 61 | + * <p> Note that while this method is very convenient, using it will imply | |
| 62 | + * an assumed reference to the default {@code FileSystem} and limit the | |
| 63 | + * utility of the calling code. Hence it should not be used in library code | |
| 64 | + * intended for flexible reuse. A more flexible alternative is to use an | |
| 65 | + * existing {@code Path} instance as an anchor, such as: | |
| 66 | + * <pre> | |
| 67 | + * Path dir = ... | |
| 68 | + * Path path = dir.resolve("file"); | |
| 69 | + * </pre> | |
| 70 | + * | |
| 71 | + * @param first | |
| 72 | + * the path string or initial part of the path string | |
| 73 | + * @param more | |
| 74 | + * additional strings to be joined to form the path string | |
| 75 | + * | |
| 76 | + * @return the resulting {@code Path} | |
| 77 | + * | |
| 78 | + * @throws InvalidPathException | |
| 79 | + * if the path string cannot be converted to a {@code Path} | |
| 80 | + * | |
| 81 | + * @see FileSystem#getPath | |
| 82 | + */ | |
| 83 | + public static Path get(String first, String... more) { | |
| 84 | + return FileSystems.getDefault().getPath(first, more); | |
| 85 | + } | |
| 86 | + | |
| 87 | + /** | |
| 88 | + * Converts the given URI to a {@link Path} object. | |
| 89 | + * | |
| 90 | + * <p> This method iterates over the {@link FileSystemProvider#installedProviders() | |
| 91 | + * installed} providers to locate the provider that is identified by the | |
| 92 | + * URI {@link URI#getScheme scheme} of the given URI. URI schemes are | |
| 93 | + * compared without regard to case. If the provider is found then its {@link | |
| 94 | + * FileSystemProvider#getPath getPath} method is invoked to convert the | |
| 95 | + * URI. | |
| 96 | + * | |
| 97 | + * <p> In the case of the default provider, identified by the URI scheme | |
| 98 | + * "file", the given URI has a non-empty path component, and undefined query | |
| 99 | + * and fragment components. Whether the authority component may be present | |
| 100 | + * is platform specific. The returned {@code Path} is associated with the | |
| 101 | + * {@link FileSystems#getDefault default} file system. | |
| 102 | + * | |
| 103 | + * <p> The default provider provides a similar <em>round-trip</em> guarantee | |
| 104 | + * to the {@link java.io.File} class. For a given {@code Path} <i>p</i> it | |
| 105 | + * is guaranteed that | |
| 106 | + * <blockquote><tt> | |
| 107 | + * Paths.get(</tt><i>p</i><tt>.{@link Path#toUri() toUri}()).equals(</tt> | |
| 108 | + * <i>p</i><tt>.{@link Path#toAbsolutePath() toAbsolutePath}())</tt> | |
| 109 | + * </blockquote> | |
| 110 | + * so long as the original {@code Path}, the {@code URI}, and the new {@code | |
| 111 | + * Path} are all created in (possibly different invocations of) the same | |
| 112 | + * Java virtual machine. Whether other providers make any guarantees is | |
| 113 | + * provider specific and therefore unspecified. | |
| 114 | + * | |
| 115 | + * @param uri | |
| 116 | + * the URI to convert | |
| 117 | + * | |
| 118 | + * @return the resulting {@code Path} | |
| 119 | + * | |
| 120 | + * @throws IllegalArgumentException | |
| 121 | + * if preconditions on the {@code uri} parameter do not hold. The | |
| 122 | + * format of the URI is provider specific. | |
| 123 | + * @throws FileSystemNotFoundException | |
| 124 | + * The file system, identified by the URI, does not exist and | |
| 125 | + * cannot be created automatically, or the provider identified by | |
| 126 | + * the URI's scheme component is not installed | |
| 127 | + * @throws SecurityException | |
| 128 | + * if a security manager is installed and it denies an unspecified | |
| 129 | + * permission to access the file system | |
| 130 | + */ | |
| 131 | + public static Path get(URI uri) { | |
| 132 | + String scheme = uri.getScheme(); | |
| 133 | + if (scheme == null) | |
| 134 | + throw new IllegalArgumentException("Missing scheme"); | |
| 135 | + | |
| 136 | + // check for default provider to avoid loading of installed providers | |
| 137 | + if (scheme.equalsIgnoreCase("file")) | |
| 138 | + return FileSystems.getDefault().provider().getPath(uri); | |
| 139 | + | |
| 140 | + // try to find provider | |
| 141 | + for (FileSystemProvider provider: FileSystemProvider.installedProviders()) { | |
| 142 | + if (provider.getScheme().equalsIgnoreCase(scheme)) { | |
| 143 | + return provider.getPath(uri); | |
| 144 | + } | |
| 145 | + } | |
| 146 | + | |
| 147 | + throw new FileSystemNotFoundException("Provider \"" + scheme + "\" not installed"); | |
| 148 | + } | |
| 149 | +} | |