src.java.compiler.share.classes.javax.annotation.processing.Filer Maven / Gradle / Ivy
Show all versions of nb-javac Show documentation
/*
* Copyright (c) 2005, 2023, 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.annotation.processing;
import javax.tools.JavaFileManager;
import javax.tools.*;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.lang.model.util.Elements;
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.
*
* 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
* "path-rootless" rule of RFC 3986, section
* 3.3.
*
*
The file creation methods take a variable number of arguments to
* allow the originating elements to be provided as hints to
* the tool infrastructure to better manage dependencies. The
* originating elements are the classes or interfaces or packages
* (representing {@code package-info} files) or modules (representing
* {@code module-info} files) which caused an annotation processor to
* attempt to create a new file.
* In other words, the originating elements are intended to have the
* granularity of compilation units (JLS section {@jls 7.3}),
* essentially file-level granularity, rather than finer-scale
* granularity of, say, a method or field declaration.
*
*
For example, if an annotation
* processor tries to create a source file, {@code
* GeneratedFromUserSource}, in response to processing
*
*
* @Generate
* public class UserSource {}
*
*
* the type element for {@code UserSource} should be passed as part of
* the creation method call as in:
*
*
* filer.createSourceFile("GeneratedFromUserSource",
* eltUtils.getTypeElement("UserSource"));
*
*
* 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.
*
* 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}.
*
*
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 class or interface, 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.
*
*
Processors can indicate a source or class file is generated by
* including a {@link javax.annotation.processing.Generated}
* annotation if the environment is configured so that that class or
* interface is accessible.
*
* @spec https://www.rfc-editor.org/info/rfc3986
* RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
* @apiNote Some of the effect of overwriting a file can be
* achieved by using a decorator-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.
*
* @since 1.6
*/
public interface Filer {
// Maintenance note: if the ability to create module-info files
// through the Filer is added, add link to this method from
// ModuleElement interface-level discussion.
/**
* Creates a new source file and returns an object to allow
* writing to it. A source file for a class, interface, or a
* package can be created.
*
* The file's name and path (relative to the {@linkplain
* StandardLocation#SOURCE_OUTPUT root output location for source
* files}) are based on the name of the item to be declared in
* that file as well as the specified module for the item (if
* any).
*
* If more than one class or interface is being declared in a single file (that
* is, a single compilation unit), the name of the file should
* correspond to the name of the principal top-level class or interface (the
* public one, for example).
*
*
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 the {@code name} argument be the
* package's name followed by {@code ".package-info"}; to create a
* source file for an unnamed package, use {@code "package-info"}.
*
*
The optional module name is prefixed to the type name or
* package name and separated using a "{@code /}" character. For
* example, to create a source file for class {@code a.B} in module
* {@code foo}, use a {@code name} argument of {@code "foo/a.B"}.
*
*
If no explicit module prefix is given and modules are supported
* in the environment, a suitable module is inferred. If a suitable
* module cannot be inferred {@link FilerException} is thrown.
* An implementation may use information about the configuration of
* the annotation processing tool as part of the inference.
*
*
Creating a source file in or for an unnamed package in a named
* module is not supported.
*
*
If the environment is configured to support implicitly declared
* classes, the name argument is used to provide the leading component of the
* name used for the output file. For example {@code filer.createSourceFile("Foo")}
* to create an implicitly declared class hosted in {@code Foo.java}. All
* implicitly declared classes must be in an unnamed package.
*
* @apiNote 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.
*
*
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.
*
* @implNote In the reference implementation, if the annotation
* processing tool is processing a single module M,
* then M is used as the module for files created without
* an explicit module prefix. If the tool is processing multiple
* modules, and {@link
* Elements#getPackageElement(java.lang.CharSequence)
* Elements.getPackageElement(package-of(name))}
* returns a package, the module that owns the returned package is used
* as the target module. A separate option may be used to provide the target
* module if it cannot be determined using the above rules.
*
* @param name canonical (fully qualified) name of the principal class or interface
* being declared in this file or a package name followed by
* {@code ".package-info"} for a package information file
* @param originatingElements class, interface, package, or module
* 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 class or interface has already been created, the name is
* otherwise not valid for the entity requested to being created,
* if the target module cannot be determined, if the target
* module is not writable, or a module is specified when the environment
* doesn't support modules.
* @throws IOException if the file cannot be created
* @jls 7.3 Compilation Units
*/
JavaFileObject createSourceFile(CharSequence name,
Element... originatingElements) throws IOException;
// Maintenance note: if the ability to create module-info files
// through the Filer is added, add link to this method from
// ModuleElement interface-level discussion.
/**
* Creates a new class file, and returns an object to allow
* writing to it. A class file for a class, interface, or a package can
* be created.
*
* 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 item to be declared as
* well as the specified module for the item (if any).
*
*
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 the {@code name} argument be the
* package's name followed by {@code ".package-info"}; creating a
* class file for an unnamed package is not supported.
*
*
The optional module name is prefixed to the type name or
* package name and separated using a "{@code /}" character. For
* example, to create a class file for class {@code a.B} in module
* {@code foo}, use a {@code name} argument of {@code "foo/a.B"}.
*
*
If no explicit module prefix is given and modules are supported
* in the environment, a suitable module is inferred. If a suitable
* module cannot be inferred {@link FilerException} is thrown.
* An implementation may use information about the configuration of
* the annotation processing tool as part of the inference.
*
*
Creating a class file in or for an unnamed package in a named
* module is not supported.
*
*
If the environment is configured to support implicitly declared
* classes, the name argument is used to provide the leading component of the
* name used for the output file. For example {@code filer.createSourceFile("Foo")}
* to create an implicitly declared class hosted in {@code Foo.java}. All
* implicitly declared classes must be in an unnamed package.
*
* @apiNote 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.
*
* @implNote In the reference implementation, if the annotation
* processing tool is processing a single module M,
* then M is used as the module for files created without
* an explicit module prefix. If the tool is processing multiple
* modules, and {@link
* Elements#getPackageElement(java.lang.CharSequence)
* Elements.getPackageElement(package-of(name))}
* returns a package, the module that owns the returned package is used
* as the target module. A separate option may be used to provide the target
* module if it cannot be determined using the above rules.
*
* @param name binary name of the class or interface being written
* or a package name followed by {@code ".package-info"} for a
* package information file
* @param originatingElements class or interface or package or
* module 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 class or interface has already been created, the name is
* not valid for a class or interface, if the target module cannot be determined,
* if the target module is not writable, or a module is specified when
* the environment doesn't support modules.
* @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 module
* and/or 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 moduleAndPkg}, and {@code relativeName}.
*
* If {@code moduleAndPkg} contains a "{@code /}" character, the
* prefix before the "{@code /}" character is the module name and
* the suffix after the "{@code /}" character is the package
* name. The package suffix may be empty. If {@code moduleAndPkg}
* does not contain a "{@code /}" character, the entire argument
* is interpreted as a package name.
*
*
If the given location is neither a {@linkplain
* JavaFileManager.Location#isModuleOrientedLocation()
* module oriented location}, nor an {@linkplain
* JavaFileManager.Location#isOutputLocation()
* output location containing multiple modules}, and the explicit
* module prefix is given, {@link FilerException} is thrown.
*
*
If the given location is either a module oriented location,
* or an output location containing multiple modules, and no explicit
* modules prefix is given, a suitable module is
* inferred. If a suitable module cannot be inferred {@link
* FilerException} is thrown. An implementation may use information
* about the configuration of the annotation processing tool
* as part of the inference.
*
*
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.
*
* @implNote In the reference implementation, if the annotation
* processing tool is processing a single module M,
* then M is used as the module for files created without
* an explicit module prefix. If the tool is processing multiple
* modules, and {@link
* Elements#getPackageElement(java.lang.CharSequence)
* Elements.getPackageElement(package-of(name))}
* returns a package, the module that owns the returned package is used
* as the target module. A separate option may be used to provide the target
* module if it cannot be determined using the above rules.
*
* @param location location of the new file
* @param moduleAndPkg module and/or 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 class or interface or package or
* module 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, if the target module cannot be determined,
* or if the target module is not writable, or if an explicit
* target module is specified and the location does not support it.
* @throws IllegalArgumentException for an unsupported location
* @throws IllegalArgumentException if {@code moduleAndPkg} is ill-formed
* @throws IllegalArgumentException if {@code relativeName} is not relative
*/
FileObject createResource(JavaFileManager.Location location,
CharSequence moduleAndPkg,
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.
*
*
If {@code moduleAndPkg} contains a "{@code /}" character, the
* prefix before the "{@code /}" character is the module name and
* the suffix after the "{@code /}" character is the package
* name. The package suffix may be empty; however, if a module
* name is present, it must be nonempty. If {@code moduleAndPkg}
* does not contain a "{@code /}" character, the entire argument
* is interpreted as a package name.
*
*
If the given location is neither a {@linkplain
* JavaFileManager.Location#isModuleOrientedLocation()
* module oriented location}, nor an {@linkplain
* JavaFileManager.Location#isOutputLocation()
* output location containing multiple modules}, and the explicit
* module prefix is given, {@link FilerException} is thrown.
*
*
If the given location is either a module oriented location,
* or an output location containing multiple modules, and no explicit
* modules prefix is given, a suitable module is
* inferred. If a suitable module cannot be inferred {@link
* FilerException} is thrown. An implementation may use information
* about the configuration of the annotation processing tool
* as part of the inference.
*
* @implNote In the reference implementation, if the annotation
* processing tool is processing a single module M,
* then M is used as the module for files read without
* an explicit module prefix. If the tool is processing multiple
* modules, and {@link
* Elements#getPackageElement(java.lang.CharSequence)
* Elements.getPackageElement(package-of(name))}
* returns a package, the module that owns the returned package is used
* as the source module. A separate option may be used to provide the target
* module if it cannot be determined using the above rules.
*
* @param location location of the file
* @param moduleAndPkg module and/or package relative to which the file
* should be searched for, 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, if the source module cannot be determined,
* or if the target module is not writable, or if an explicit target
* module is specified and the location does not support it.
* @throws IOException if the file cannot be opened
* @throws IllegalArgumentException for an unsupported location
* @throws IllegalArgumentException if {@code moduleAndPkg} is ill-formed
* @throws IllegalArgumentException if {@code relativeName} is not relative
*/
FileObject getResource(JavaFileManager.Location location,
CharSequence moduleAndPkg,
CharSequence relativeName) throws IOException;
}