Mercurial > jdk8-mips64-public > langtools / file comparison

comparison: src/share/classes/javax/annotation/processing/Filer.java

src/share/classes/javax/annotation/processing/Filer.java

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1 /*
2 * Copyright (c) 2005, 2006, 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 javax.annotation.processing;
27
28 import javax.tools.JavaFileManager;
29 import javax.tools.*;
30 import javax.lang.model.element.Element;
31 import java.io.IOException;
32
33 /**
34 * This interface supports the creation of new files by an annotation
35 * processor. Files created in this way will be known to the
36 * annotation processing tool implementing this interface, better
37 * enabling the tool to manage them. Source and class files so
38 * created will be {@linkplain RoundEnvironment#getRootElements
39 * considered for processing} by the tool in a subsequent {@linkplain
40 * RoundEnvironment round of processing} after the {@code close}
41 * method has been called on the {@code Writer} or {@code
42 * OutputStream} used to write the contents of the file.
43 *
44 * Three kinds of files are distinguished: source files, class files,
45 * and auxiliary resource files.
46 *
47 * <p> There are two distinguished supported locations (subtrees
48 * within the logical file system) where newly created files are
49 * placed: one for {@linkplain
50 * javax.tools.StandardLocation#SOURCE_OUTPUT new source files}, and
51 * one for {@linkplain javax.tools.StandardLocation#CLASS_OUTPUT new
52 * class files}. (These might be specified on a tool's command line,
53 * for example, using flags such as {@code -s} and {@code -d}.) The
54 * actual locations for new source files and new class files may or
55 * may not be distinct on a particular run of the tool. Resource
56 * files may be created in either location. The methods for reading
57 * and writing resources take a relative name argument. A relative
58 * name is a non-null, non-empty sequence of path segments separated
59 * by {@code '/'}; {@code '.'} and {@code '..'} are invalid path
60 * segments. A valid relative name must match the
61 * &quot;path-rootless&quot; rule of <a
62 * href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986</a>, section
63 * 3.3.
64 *
65 * <p>The file creation methods take a variable number of arguments to
66 * allow the <em>originating elements</em> to be provided as hints to
67 * the tool infrastructure to better manage dependencies. The
68 * originating elements are the types or packages (representing {@code
69 * package-info} files) which caused an annotation processor to
70 * attempt to create a new file. For example, if an annotation
71 * processor tries to create a source file, {@code
72 * GeneratedFromUserSource}, in response to processing
73 *
74 * <blockquote><pre>
75 * &#64;Generate
76 * public class UserSource {}
77 * </pre></blockquote>
78 *
79 * the type element for {@code UserSource} should be passed as part of
80 * the creation method call as in:
81 *
82 * <blockquote><pre>
83 * filer.createSourceFile("GeneratedFromUserSource",
84 * eltUtils.getTypeElement("UserSource"));
85 * </pre></blockquote>
86 *
87 * If there are no originating elements, none need to be passed. This
88 * information may be used in an incremental environment to determine
89 * the need to rerun processors or remove generated files.
90 * Non-incremental environments may ignore the originating element
91 * information.
92 *
93 * <p> During each run of an annotation processing tool, a file with a
94 * given pathname may be created only once. If that file already
95 * exists before the first attempt to create it, the old contents will
96 * be deleted. Any subsequent attempt to create the same file during
97 * a run will throw a {@link FilerException}, as will attempting to
98 * create both a class file and source file for the same type name or
99 * same package name. The {@linkplain Processor initial inputs} to
100 * the tool are considered to be created by the zeroth round;
101 * therefore, attempting to create a source or class file
102 * corresponding to one of those inputs will result in a {@link
103 * FilerException}.
104 *
105 * <p> In general, processors must not knowingly attempt to overwrite
106 * existing files that were not generated by some processor. A {@code
107 * Filer} may reject attempts to open a file corresponding to an
108 * existing type, like {@code java.lang.Object}. Likewise, the
109 * invoker of the annotation processing tool must not knowingly
110 * configure the tool such that the discovered processors will attempt
111 * to overwrite existing files that were not generated.
112 *
113 * <p> Processors can indicate a source or class file is generated by
114 * including an {@link javax.annotation.Generated @Generated}
115 * annotation.
116 *
117 * <p> Note that some of the effect of overwriting a file can be
118 * achieved by using a <i>decorator</i>-style pattern. Instead of
119 * modifying a class directly, the class is designed so that either
120 * its superclass is generated by annotation processing or subclasses
121 * of the class are generated by annotation processing. If the
122 * subclasses are generated, the parent class may be designed to use
123 * factories instead of public constructors so that only subclass
124 * instances would be presented to clients of the parent class.
125 *
126 * @author Joseph D. Darcy
127 * @author Scott Seligman
128 * @author Peter von der Ah&eacute;
129 * @since 1.6
130 */
131 public interface Filer {
132 /**
133 * Creates a new source file and returns an object to allow
134 * writing to it. The file's name and path (relative to the
135 * {@linkplain StandardLocation#SOURCE_OUTPUT root output location
136 * for source files}) are based on the type to be declared in that
137 * file. If more than one type is being declared, the name of the
138 * principal top-level type (the public one, for example) should
139 * be used. A source file can also be created to hold information
140 * about a package, including package annotations. To create a
141 * source file for a named package, have {@code name} be the
142 * package's name followed by {@code ".package-info"}; to create a
143 * source file for an unnamed package, use {@code "package-info"}.
144 *
145 * <p> Note that to use a particular {@linkplain
146 * java.nio.charset.Charset charset} to encode the contents of the
147 * file, an {@code OutputStreamWriter} with the chosen charset can
148 * be created from the {@code OutputStream} from the returned
149 * object. If the {@code Writer} from the returned object is
150 * directly used for writing, its charset is determined by the
151 * implementation. An annotation processing tool may have an
152 * {@code -encoding} flag or analogous option for specifying this;
153 * otherwise, it will typically be the platform's default
154 * encoding.
155 *
156 * <p>To avoid subsequent errors, the contents of the source file
157 * should be compatible with the {@linkplain
158 * ProcessingEnvironment#getSourceVersion source version} being used
159 * for this run.
160 *
161 * @param name canonical (fully qualified) name of the principal type
162 * being declared in this file or a package name followed by
163 * {@code ".package-info"} for a package information file
164 * @param originatingElements type or package elements causally
165 * associated with the creation of this file, may be elided or
166 * {@code null}
167 * @return a {@code JavaFileObject} to write the new source file
168 * @throws FilerException if the same pathname has already been
169 * created, the same type has already been created, or the name is
170 * not valid for a type
171 * @throws IOException if the file cannot be created
172 */
173 JavaFileObject createSourceFile(CharSequence name,
174 Element... originatingElements) throws IOException;
175
176 /**
177 * Creates a new class file, and returns an object to allow
178 * writing to it. The file's name and path (relative to the
179 * {@linkplain StandardLocation#CLASS_OUTPUT root output location
180 * for class files}) are based on the name of the type being
181 * written. A class file can also be created to hold information
182 * about a package, including package annotations. To create a
183 * class file for a named package, have {@code name} be the
184 * package's name followed by {@code ".package-info"}; creating a
185 * class file for an unnamed package is not supported.
186 *
187 * <p>To avoid subsequent errors, the contents of the class file
188 * should be compatible with the {@linkplain
189 * ProcessingEnvironment#getSourceVersion source version} being used
190 * for this run.
191 *
192 * @param name binary name of the type being written or a package name followed by
193 * {@code ".package-info"} for a package information file
194 * @param originatingElements type or package elements causally
195 * associated with the creation of this file, may be elided or
196 * {@code null}
197 * @return a {@code JavaFileObject} to write the new class file
198 * @throws FilerException if the same pathname has already been
199 * created, the same type has already been created, or the name is
200 * not valid for a type
201 * @throws IOException if the file cannot be created
202 */
203 JavaFileObject createClassFile(CharSequence name,
204 Element... originatingElements) throws IOException;
205
206 /**
207 * Creates a new auxiliary resource file for writing and returns a
208 * file object for it. The file may be located along with the
209 * newly created source files, newly created binary files, or
210 * other supported location. The locations {@link
211 * StandardLocation#CLASS_OUTPUT CLASS_OUTPUT} and {@link
212 * StandardLocation#SOURCE_OUTPUT SOURCE_OUTPUT} must be
213 * supported. The resource may be named relative to some package
214 * (as are source and class files), and from there by a relative
215 * pathname. In a loose sense, the full pathname of the new file
216 * will be the concatenation of {@code location}, {@code pkg}, and
217 * {@code relativeName}.
218 *
219 * <p>Files created via this method are not registered for
220 * annotation processing, even if the full pathname of the file
221 * would correspond to the full pathname of a new source file
222 * or new class file.
223 *
224 * @param location location of the new file
225 * @param pkg package relative to which the file should be named,
226 * or the empty string if none
227 * @param relativeName final pathname components of the file
228 * @param originatingElements type or package elements causally
229 * associated with the creation of this file, may be elided or
230 * {@code null}
231 * @return a {@code FileObject} to write the new resource
232 * @throws IOException if the file cannot be created
233 * @throws FilerException if the same pathname has already been
234 * created
235 * @throws IllegalArgumentException for an unsupported location
236 * @throws IllegalArgumentException if {@code relativeName} is not relative
237 */
238 FileObject createResource(JavaFileManager.Location location,
239 CharSequence pkg,
240 CharSequence relativeName,
241 Element... originatingElements) throws IOException;
242
243 /**
244 * Returns an object for reading an existing resource. The
245 * locations {@link StandardLocation#CLASS_OUTPUT CLASS_OUTPUT}
246 * and {@link StandardLocation#SOURCE_OUTPUT SOURCE_OUTPUT} must
247 * be supported.
248 *
249 * @param location location of the file
250 * @param pkg package relative to which the file should be searched,
251 * or the empty string if none
252 * @param relativeName final pathname components of the file
253 * @return an object to read the file
254 * @throws FilerException if the same pathname has already been
255 * opened for writing
256 * @throws IOException if the file cannot be opened
257 * @throws IllegalArgumentException for an unsupported location
258 * @throws IllegalArgumentException if {@code relativeName} is not relative
259 */
260 FileObject getResource(JavaFileManager.Location location,
261 CharSequence pkg,
262 CharSequence relativeName) throws IOException;
263 }

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