/*
 * @(#)Filer.java	1.1 04/01/26
 *
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL.  Use is subject to license terms.
 */

package com.sun.mirror.apt;


import java.io.*;


/**
 * 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 <i>auxiliary</i> files.
 *
 * <p> 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 <tt>-s</tt> and <tt>-d</tt>.)
 * Auxiliary files may be created in either location.
 *
 * <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 fail.
 *
 * @author Joseph D. Darcy
 * @author Scott Seligman
 * @version 1.1 04/01/26
 * @since 1.5
 */

public interface Filer {

    /**
     * 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.
     *
     * <p> The {@linkplain java.nio.charset.Charset charset} used to
     * encode the file is determined by the implementation.
     * An annotation processing tool may have an <tt>-encoding</tt>
     * flag or the like for specifying this.  It will typically use
     * the platform's default encoding if none is specified.
     *
     * @param name  canonical (fully qualified) name of the principal type
     *		being declared in this file
     * @return a writer for the new file
     * @throws IOException if the file cannot be created
     */
    PrintWriter createSourceFile(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.
     *
     * @param name canonical (fully qualified) name of the type being written
     * @return a stream for writing to the new file
     * @throws IOException if the file cannot be created
     */
    OutputStream createClassFile(String name) 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
     * <tt>loc</tt>, <tt>pkg</tt>, and <tt>relPath</tt>.
     *
     * <p> A {@linkplain java.nio.charset.Charset charset} for
     * encoding the file may be provided.  If none is given, the
     * charset used to encode source files
     * (see {@link #createSourceFile(String)}) will be used.
     *
     * @param loc location of the new file
     * @param pkg package relative to which the file should be named,
     *		or the empty string if none
     * @param relPath final pathname components of the file
     * @param charsetName the name of the charset to use, or null if none
     *		is being explicitly specified
     * @return a writer for the new file
     * @throws IOException if the file cannot be created
     */
    PrintWriter createTextFile(Location loc,
			       String pkg,
			       File relPath,
			       String charsetName) 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
     * <tt>loc</tt>, <tt>pkg</tt>, and <tt>relPath</tt>.
     *
     * @param loc location of the new file
     * @param pkg package relative to which the file should be named,
     *		or the empty string if none
     * @param relPath final pathname components of the file
     * @return a stream for writing to the new file
     * @throws IOException if the file cannot be created
     */
    OutputStream createBinaryFile(Location loc,
				  String pkg,
				  File relPath) throws IOException;


    /**
     * Locations (subtrees within the file system) where new files are created.
     */
    enum Location {
	/** The location of new source files. */
	SOURCE_TREE,
	/** The location of new class files. */
	CLASS_TREE
    }
}