Interface Filer


  • public interface Filer
    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. Four kinds of files are distinguished: source files, class files, other text files, and other binary files. The latter two are collectively referred to as auxiliary files.

    There are two distinguished locations (subtrees within the file system) where newly created files are placed: one for new source files, and one for new class files. (These might be specified on a tool's command line, for example, using flags such as -s and -d.) Auxiliary files may be created in either location.

    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 fail.

    Since:
    1.5
    • Method Detail

      • createSourceFile

        PrintWriter createSourceFile​(String name)
                              throws IOException
        Creates a new source file and returns a writer for it. The file's name and path (relative to the root of all newly created source files) is 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.

        The charset used to encode the file is determined by the implementation. An annotation processing tool may have an -encoding flag or the like for specifying this. It will typically use the platform's default encoding if none is specified.

        Parameters:
        name - canonical (fully qualified) name of the principal type being declared in this file
        Returns:
        a writer for the new file
        Throws:
        IOException - if the file cannot be created
      • createClassFile

        OutputStream createClassFile​(String name)
                              throws IOException
        Creates a new class file, and returns a stream for writing to it. The file's name and path (relative to the root of all newly created class files) is based on the name of the type being written.
        Parameters:
        name - canonical (fully qualified) name of the type being written
        Returns:
        a stream for writing to the new file
        Throws:
        IOException - if the file cannot be created
      • createTextFile

        PrintWriter createTextFile​(Filer.Location loc,
                                   String pkg,
                                   File relPath,
                                   String charsetName)
                            throws IOException
        Creates a new text file, and returns a writer for it. The file is located along with either the newly created source or newly created binary files. It may be named relative to some package (as are source and binary files), and from there by an arbitrary pathname. In a loose sense, the pathname of the new file will be the concatenation of loc, pkg, and relPath.

        A charset for encoding the file may be provided. If none is given, the charset used to encode source files (see createSourceFile(String)) will be used.

        Parameters:
        loc - location of the new file
        pkg - package relative to which the file should be named, or the empty string if none
        relPath - final pathname components of the file
        charsetName - the name of the charset to use, or null if none is being explicitly specified
        Returns:
        a writer for the new file
        Throws:
        IOException - if the file cannot be created
      • createBinaryFile

        OutputStream createBinaryFile​(Filer.Location loc,
                                      String pkg,
                                      File relPath)
                               throws IOException
        Creates a new binary file, and returns a stream for writing to it. The file is located along with either the newly created source or newly created binary files. It may be named relative to some package (as are source and binary files), and from there by an arbitrary pathname. In a loose sense, the pathname of the new file will be the concatenation of loc, pkg, and relPath.
        Parameters:
        loc - location of the new file
        pkg - package relative to which the file should be named, or the empty string if none
        relPath - final pathname components of the file
        Returns:
        a stream for writing to the new file
        Throws:
        IOException - if the file cannot be created