1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | |
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19 | package org.apache.hadoop.fs; |
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20 | |
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21 | import java.net.*; |
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22 | import java.io.*; |
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23 | |
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24 | import org.apache.hadoop.conf.Configuration; |
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25 | |
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26 | /** Names a file or directory in a {@link FileSystem}. |
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27 | * Path strings use slash as the directory separator. A path string is |
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28 | * absolute if it begins with a slash. |
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29 | */ |
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30 | public class Path implements Comparable { |
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31 | |
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32 | /** The directory separator, a slash. */ |
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33 | public static final String SEPARATOR = "/"; |
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34 | public static final char SEPARATOR_CHAR = '/'; |
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35 | |
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36 | public static final String CUR_DIR = "."; |
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37 | |
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38 | static final boolean WINDOWS |
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39 | = System.getProperty("os.name").startsWith("Windows"); |
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40 | |
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41 | private URI uri; // a hierarchical uri |
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42 | |
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43 | /** Resolve a child path against a parent path. */ |
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44 | public Path(String parent, String child) { |
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45 | this(new Path(parent), new Path(child)); |
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46 | } |
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47 | |
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48 | /** Resolve a child path against a parent path. */ |
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49 | public Path(Path parent, String child) { |
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50 | this(parent, new Path(child)); |
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51 | } |
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52 | |
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53 | /** Resolve a child path against a parent path. */ |
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54 | public Path(String parent, Path child) { |
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55 | this(new Path(parent), child); |
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56 | } |
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57 | |
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58 | /** Resolve a child path against a parent path. */ |
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59 | public Path(Path parent, Path child) { |
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60 | // Add a slash to parent's path so resolution is compatible with URI's |
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61 | URI parentUri = parent.uri; |
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62 | String parentPath = parentUri.getPath(); |
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63 | if (!(parentPath.equals("/") || parentPath.equals(""))) |
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64 | try { |
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65 | parentUri = new URI(parentUri.getScheme(), parentUri.getAuthority(), |
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66 | parentUri.getPath()+"/", null, null); |
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67 | } catch (URISyntaxException e) { |
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68 | throw new IllegalArgumentException(e); |
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69 | } |
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70 | URI resolved = parentUri.resolve(child.uri); |
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71 | initialize(resolved.getScheme(), resolved.getAuthority(), |
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72 | normalizePath(resolved.getPath())); |
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73 | } |
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74 | |
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75 | private void checkPathArg( String path ) { |
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76 | // disallow construction of a Path from an empty string |
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77 | if ( path == null ) { |
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78 | throw new IllegalArgumentException( |
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79 | "Can not create a Path from a null string"); |
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80 | } |
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81 | if( path.length() == 0 ) { |
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82 | throw new IllegalArgumentException( |
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83 | "Can not create a Path from an empty string"); |
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84 | } |
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85 | } |
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86 | |
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87 | /** Construct a path from a String. Path strings are URIs, but with |
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88 | * unescaped elements and some additional normalization. */ |
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89 | public Path(String pathString) { |
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90 | checkPathArg( pathString ); |
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91 | |
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92 | // We can't use 'new URI(String)' directly, since it assumes things are |
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93 | // escaped, which we don't require of Paths. |
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94 | |
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95 | // add a slash in front of paths with Windows drive letters |
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96 | if (hasWindowsDrive(pathString, false)) |
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97 | pathString = "/"+pathString; |
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98 | |
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99 | // parse uri components |
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100 | String scheme = null; |
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101 | String authority = null; |
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102 | |
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103 | int start = 0; |
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104 | |
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105 | // parse uri scheme, if any |
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106 | int colon = pathString.indexOf(':'); |
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107 | int slash = pathString.indexOf('/'); |
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108 | if ((colon != -1) && |
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109 | ((slash == -1) || (colon < slash))) { // has a scheme |
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110 | scheme = pathString.substring(0, colon); |
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111 | start = colon+1; |
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112 | } |
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113 | |
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114 | // parse uri authority, if any |
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115 | if (pathString.startsWith("//", start) && |
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116 | (pathString.length()-start > 2)) { // has authority |
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117 | int nextSlash = pathString.indexOf('/', start+2); |
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118 | int authEnd = nextSlash > 0 ? nextSlash : pathString.length(); |
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119 | authority = pathString.substring(start+2, authEnd); |
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120 | start = authEnd; |
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121 | } |
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122 | |
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123 | // uri path is the rest of the string -- query & fragment not supported |
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124 | String path = pathString.substring(start, pathString.length()); |
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125 | |
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126 | initialize(scheme, authority, path); |
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127 | } |
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128 | |
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129 | /** Construct a Path from components. */ |
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130 | public Path(String scheme, String authority, String path) { |
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131 | checkPathArg( path ); |
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132 | initialize(scheme, authority, path); |
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133 | } |
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134 | |
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135 | private void initialize(String scheme, String authority, String path) { |
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136 | try { |
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137 | this.uri = new URI(scheme, authority, normalizePath(path), null, null) |
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138 | .normalize(); |
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139 | } catch (URISyntaxException e) { |
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140 | throw new IllegalArgumentException(e); |
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141 | } |
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142 | } |
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143 | |
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144 | private String normalizePath(String path) { |
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145 | // remove double slashes & backslashes |
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146 | path = path.replace("//", "/"); |
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147 | path = path.replace("\\", "/"); |
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148 | |
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149 | // trim trailing slash from non-root path (ignoring windows drive) |
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150 | int minLength = hasWindowsDrive(path, true) ? 4 : 1; |
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151 | if (path.length() > minLength && path.endsWith("/")) { |
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152 | path = path.substring(0, path.length()-1); |
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153 | } |
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154 | |
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155 | return path; |
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156 | } |
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157 | |
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158 | private boolean hasWindowsDrive(String path, boolean slashed) { |
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159 | if (!WINDOWS) return false; |
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160 | int start = slashed ? 1 : 0; |
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161 | return |
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162 | path.length() >= start+2 && |
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163 | (slashed ? path.charAt(0) == '/' : true) && |
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164 | path.charAt(start+1) == ':' && |
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165 | ((path.charAt(start) >= 'A' && path.charAt(start) <= 'Z') || |
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166 | (path.charAt(start) >= 'a' && path.charAt(start) <= 'z')); |
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167 | } |
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168 | |
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169 | |
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170 | /** Convert this to a URI. */ |
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171 | public URI toUri() { return uri; } |
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172 | |
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173 | /** Return the FileSystem that owns this Path. */ |
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174 | public FileSystem getFileSystem(Configuration conf) throws IOException { |
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175 | return FileSystem.get(this.toUri(), conf); |
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176 | } |
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177 | |
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178 | /** True if the directory of this path is absolute. */ |
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179 | public boolean isAbsolute() { |
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180 | int start = hasWindowsDrive(uri.getPath(), true) ? 3 : 0; |
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181 | return uri.getPath().startsWith(SEPARATOR, start); |
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182 | } |
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183 | |
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184 | /** Returns the final component of this path.*/ |
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185 | public String getName() { |
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186 | String path = uri.getPath(); |
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187 | int slash = path.lastIndexOf(SEPARATOR); |
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188 | return path.substring(slash+1); |
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189 | } |
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190 | |
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191 | /** Returns the parent of a path or null if at root. */ |
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192 | public Path getParent() { |
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193 | String path = uri.getPath(); |
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194 | int lastSlash = path.lastIndexOf('/'); |
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195 | int start = hasWindowsDrive(path, true) ? 3 : 0; |
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196 | if ((path.length() == start) || // empty path |
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197 | (lastSlash == start && path.length() == start+1)) { // at root |
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198 | return null; |
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199 | } |
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200 | String parent; |
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201 | if (lastSlash==-1) { |
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202 | parent = CUR_DIR; |
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203 | } else { |
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204 | int end = hasWindowsDrive(path, true) ? 3 : 0; |
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205 | parent = path.substring(0, lastSlash==end?end+1:lastSlash); |
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206 | } |
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207 | return new Path(uri.getScheme(), uri.getAuthority(), parent); |
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208 | } |
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209 | |
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210 | /** Adds a suffix to the final name in the path.*/ |
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211 | public Path suffix(String suffix) { |
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212 | return new Path(getParent(), getName()+suffix); |
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213 | } |
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214 | |
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215 | public String toString() { |
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216 | // we can't use uri.toString(), which escapes everything, because we want |
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217 | // illegal characters unescaped in the string, for glob processing, etc. |
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218 | StringBuffer buffer = new StringBuffer(); |
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219 | if (uri.getScheme() != null) { |
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220 | buffer.append(uri.getScheme()); |
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221 | buffer.append(":"); |
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222 | } |
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223 | if (uri.getAuthority() != null) { |
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224 | buffer.append("//"); |
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225 | buffer.append(uri.getAuthority()); |
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226 | } |
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227 | if (uri.getPath() != null) { |
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228 | String path = uri.getPath(); |
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229 | if (path.indexOf('/')==0 && |
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230 | hasWindowsDrive(path, true) && // has windows drive |
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231 | uri.getScheme() == null && // but no scheme |
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232 | uri.getAuthority() == null) // or authority |
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233 | path = path.substring(1); // remove slash before drive |
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234 | buffer.append(path); |
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235 | } |
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236 | return buffer.toString(); |
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237 | } |
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238 | |
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239 | public boolean equals(Object o) { |
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240 | if (!(o instanceof Path)) { |
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241 | return false; |
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242 | } |
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243 | Path that = (Path)o; |
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244 | return this.uri.equals(that.uri); |
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245 | } |
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246 | |
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247 | public int hashCode() { |
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248 | return uri.hashCode(); |
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249 | } |
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250 | |
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251 | public int compareTo(Object o) { |
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252 | Path that = (Path)o; |
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253 | return this.uri.compareTo(that.uri); |
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254 | } |
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255 | |
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256 | /** Return the number of elements in this path. */ |
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257 | public int depth() { |
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258 | String path = uri.getPath(); |
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259 | int depth = 0; |
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260 | int slash = path.length()==1 && path.charAt(0)=='/' ? -1 : 0; |
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261 | while (slash != -1) { |
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262 | depth++; |
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263 | slash = path.indexOf(SEPARATOR, slash+1); |
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264 | } |
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265 | return depth; |
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266 | } |
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267 | |
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268 | /** Returns a qualified path object. */ |
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269 | public Path makeQualified(FileSystem fs) { |
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270 | Path path = this; |
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271 | if (!isAbsolute()) { |
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272 | path = new Path(fs.getWorkingDirectory(), this); |
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273 | } |
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274 | |
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275 | URI pathUri = path.toUri(); |
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276 | URI fsUri = fs.getUri(); |
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277 | |
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278 | String scheme = pathUri.getScheme(); |
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279 | String authority = pathUri.getAuthority(); |
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280 | |
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281 | if (scheme != null && |
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282 | (authority != null || fsUri.getAuthority() == null)) |
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283 | return path; |
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284 | |
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285 | if (scheme == null) { |
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286 | scheme = fsUri.getScheme(); |
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287 | } |
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288 | |
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289 | if (authority == null) { |
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290 | authority = fsUri.getAuthority(); |
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291 | if (authority == null) { |
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292 | authority = ""; |
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293 | } |
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294 | } |
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295 | |
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296 | return new Path(scheme+":"+"//"+authority + pathUri.getPath()); |
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297 | } |
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298 | } |
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