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

 /*

  * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 package javax.annotation.processing;

 import javax.tools.JavaFileManager;

 import javax.tools.*;

 import javax.lang.model.element.Element;

 import java.io.IOException;

 /**

  * This interface supports the creation of new files by an annotation

  * processor.  Files created in this way will be known to the

  * annotation processing tool implementing this interface, better

  * enabling the tool to manage them.  Source and class files so

  * created will be {@linkplain RoundEnvironment#getRootElements

  * considered for processing} by the tool in a subsequent {@linkplain

  * RoundEnvironment round of processing} after the {@code close}

  * method has been called on the {@code Writer} or {@code

  * OutputStream} used to write the contents of the file.

  *

  * Three kinds of files are distinguished: source files, class files,

  * and auxiliary resource files.

  *

  * <p> There are two distinguished supported locations (subtrees

  * within the logical file system) where newly created files are

  * placed: one for {@linkplain

  * javax.tools.StandardLocation#SOURCE_OUTPUT new source files}, and

  * one for {@linkplain javax.tools.StandardLocation#CLASS_OUTPUT new

  * class files}.  (These might be specified on a tool's command line,

  * for example, using flags such as {@code -s} and {@code -d}.)  The

  * actual locations for new source files and new class files may or

  * may not be distinct on a particular run of the tool.  Resource

  * files may be created in either location.  The methods for reading

  * and writing resources take a relative name argument.  A relative

  * name is a non-null, non-empty sequence of path segments separated

  * by {@code '/'}; {@code '.'} and {@code '..'} are invalid path

  * segments.  A valid relative name must match the

  * &quot;path-rootless&quot; rule of <a

  * href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986</a>, section

  * 3.3.

  *

  * <p>The file creation methods take a variable number of arguments to

  * allow the <em>originating elements</em> to be provided as hints to

  * the tool infrastructure to better manage dependencies.  The

  * originating elements are the types or packages (representing {@code

  * package-info} files) which caused an annotation processor to

  * attempt to create a new file.  For example, if an annotation

  * processor tries to create a source file, {@code

  * GeneratedFromUserSource}, in response to processing

  *

  * <blockquote><pre>

  *  @Generate

  *  public class UserSource {}

  * </pre></blockquote>

  *

  * the type element for {@code UserSource} should be passed as part of

  * the creation method call as in:

  *

  * <blockquote><pre>

  *      filer.createSourceFile("GeneratedFromUserSource",

  *                             eltUtils.getTypeElement("UserSource"));

  * </pre></blockquote>

  *

  * If there are no originating elements, none need to be passed.  This

  * information may be used in an incremental environment to determine

  * the need to rerun processors or remove generated files.

  * Non-incremental environments may ignore the originating element

  * information.

  *

  * <p> During each run of an annotation processing tool, a file with a

  * given pathname may be created only once.  If that file already

  * exists before the first attempt to create it, the old contents will

  * be deleted.  Any subsequent attempt to create the same file during

  * a run will throw a {@link FilerException}, as will attempting to

  * create both a class file and source file for the same type name or

  * same package name.  The {@linkplain Processor initial inputs} to

  * the tool are considered to be created by the zeroth round;

  * therefore, attempting to create a source or class file

  * corresponding to one of those inputs will result in a {@link

  * FilerException}.

  *

  * <p> In general, processors must not knowingly attempt to overwrite

  * existing files that were not generated by some processor.  A {@code

  * Filer} may reject attempts to open a file corresponding to an

  * existing type, like {@code java.lang.Object}.  Likewise, the

  * invoker of the annotation processing tool must not knowingly

  * configure the tool such that the discovered processors will attempt

  * to overwrite existing files that were not generated.

  *

  * <p> Processors can indicate a source or class file is generated by

  * including an {@link javax.annotation.Generated @Generated}

  * annotation.

  *

  * <p> Note that some of the effect of overwriting a file can be

  * achieved by using a <i>decorator</i>-style pattern.  Instead of

  * modifying a class directly, the class is designed so that either

  * its superclass is generated by annotation processing or subclasses

  * of the class are generated by annotation processing.  If the

  * subclasses are generated, the parent class may be designed to use

  * factories instead of public constructors so that only subclass

  * instances would be presented to clients of the parent class.

  *

  * @author Joseph D. Darcy

  * @author Scott Seligman

  * @author Peter von der Ahé

  * @since 1.6

  */

 public interface Filer {

     /**

      * Creates a new source file and returns an object to allow

      * writing to it.  The file's name and path (relative to the

      * {@linkplain StandardLocation#SOURCE_OUTPUT root output location

      * for source files}) are based on the type to be declared in that

      * file.  If more than one type is being declared, the name of the

      * principal top-level type (the public one, for example) should

      * be used.  A source file can also be created to hold information

      * about a package, including package annotations.  To create a

      * source file for a named package, have {@code name} be the

      * package's name followed by {@code ".package-info"}; to create a

      * source file for an unnamed package, use {@code "package-info"}.

      *

      * <p> Note that to use a particular {@linkplain

      * java.nio.charset.Charset charset} to encode the contents of the

      * file, an {@code OutputStreamWriter} with the chosen charset can

      * be created from the {@code OutputStream} from the returned

      * object. If the {@code Writer} from the returned object is

      * directly used for writing, its charset is determined by the

      * implementation.  An annotation processing tool may have an

      * {@code -encoding} flag or analogous option for specifying this;

      * otherwise, it will typically be the platform's default

      * encoding.

      *

      * <p>To avoid subsequent errors, the contents of the source file

      * should be compatible with the {@linkplain

      * ProcessingEnvironment#getSourceVersion source version} being used

      * for this run.

      *

      * @param name  canonical (fully qualified) name of the principal type

      *          being declared in this file or a package name followed by

      *          {@code ".package-info"} for a package information file

      * @param originatingElements type or package elements causally

      * associated with the creation of this file, may be elided or

      * {@code null}

      * @return a {@code JavaFileObject} to write the new source file

      * @throws FilerException if the same pathname has already been

      * created, the same type has already been created, or the name is

      * not valid for a type

      * @throws IOException if the file cannot be created

      */

     JavaFileObject createSourceFile(CharSequence name,

                                     Element... originatingElements) throws IOException;

     /**

      * Creates a new class file, and returns an object to allow

      * writing to it.  The file's name and path (relative to the

      * {@linkplain StandardLocation#CLASS_OUTPUT root output location

      * for class files}) are based on the name of the type being

      * written.  A class file can also be created to hold information

      * about a package, including package annotations.  To create a

      * class file for a named package, have {@code name} be the

      * package's name followed by {@code ".package-info"}; creating a

      * class file for an unnamed package is not supported.

      *

      * <p>To avoid subsequent errors, the contents of the class file

      * should be compatible with the {@linkplain

      * ProcessingEnvironment#getSourceVersion source version} being used

      * for this run.

      *

      * @param name binary name of the type being written or a package name followed by

      *          {@code ".package-info"} for a package information file

      * @param originatingElements type or package elements causally

      * associated with the creation of this file, may be elided or

      * {@code null}

      * @return a {@code JavaFileObject} to write the new class file

      * @throws FilerException if the same pathname has already been

      * created, the same type has already been created, or the name is

      * not valid for a type

      * @throws IOException if the file cannot be created

      */

     JavaFileObject createClassFile(CharSequence name,

                                    Element... originatingElements) throws IOException;

     /**

      * Creates a new auxiliary resource file for writing and returns a

      * file object for it.  The file may be located along with the

      * newly created source files, newly created binary files, or

      * other supported location.  The locations {@link

      * StandardLocation#CLASS_OUTPUT CLASS_OUTPUT} and {@link

      * StandardLocation#SOURCE_OUTPUT SOURCE_OUTPUT} must be

      * supported.  The resource may be named relative to some package

      * (as are source and class files), and from there by a relative

      * pathname.  In a loose sense, the full pathname of the new file

      * will be the concatenation of {@code location}, {@code pkg}, and

      * {@code relativeName}.

      *

      * <p>Files created via this method are not registered for

      * annotation processing, even if the full pathname of the file

      * would correspond to the full pathname of a new source file

      * or new class file.

      *

      * @param location location of the new file

      * @param pkg package relative to which the file should be named,

      *          or the empty string if none

      * @param relativeName final pathname components of the file

      * @param originatingElements type or package elements causally

      * associated with the creation of this file, may be elided or

      * {@code null}

      * @return a {@code FileObject} to write the new resource

      * @throws IOException if the file cannot be created

      * @throws FilerException if the same pathname has already been

      * created

      * @throws IllegalArgumentException for an unsupported location

      * @throws IllegalArgumentException if {@code relativeName} is not relative

      */

    FileObject createResource(JavaFileManager.Location location,

                              CharSequence pkg,

                              CharSequence relativeName,

                              Element... originatingElements) throws IOException;

     /**

      * Returns an object for reading an existing resource.  The

      * locations {@link StandardLocation#CLASS_OUTPUT CLASS_OUTPUT}

      * and {@link StandardLocation#SOURCE_OUTPUT SOURCE_OUTPUT} must

      * be supported.

      *

      * @param location location of the file

      * @param pkg package relative to which the file should be searched,

      *          or the empty string if none

      * @param relativeName final pathname components of the file

      * @return an object to read the file

      * @throws FilerException if the same pathname has already been

      * opened for writing

      * @throws IOException if the file cannot be opened

      * @throws IllegalArgumentException for an unsupported location

      * @throws IllegalArgumentException if {@code relativeName} is not relative

      */

     FileObject getResource(JavaFileManager.Location location,

                            CharSequence pkg,

                            CharSequence relativeName) throws IOException;

 }