import java.nio.file.Paths;

import java.util.LinkedHashSet;

import java.util.Set;

/**

 * Builder for module declarations.

 */

    private String comment = "";

    private List<String> requires = new ArrayList<>();

    private List<String> exports = new ArrayList<>();

    private List<String> uses = new ArrayList<>();

    private List<String> provides = new ArrayList<>();

    private Set<Path> modulePath = new LinkedHashSet<>();

    /**

     * Creates a builder for a module.

     * @param tb a Toolbox that can be used to compile the module declaration.

     * @param name the name of the module to be built

     */

    /**

     * Sets the doc comment for the declaration.

     * @param comment the content of the comment, excluding the initial

     *  '/**', leading whitespace and asterisks, and the final trailing '&#02a;/'.

     * @return this builder

     */

    public ModuleBuilder comment(String comment) {

        this.comment = comment;

        return this;

    /**

     * Adds a "requires public" directive to the declaration.

     * @param requires the name of the module that is required

     * @param modulePath a path in which to locate the modules

     *    if the declaration is compiled

     * @return this builder

     */

    public ModuleBuilder requiresPublic(String requires, Path... modulePath) {

        this.requires.add("requires public " + requires + ";");

        this.modulePath.addAll(Arrays.asList(modulePath));

        return this;

    }

    /**

     * Adds a "requires" directive to the declaration.

     * @param requires the name of the module that is required

     * @param modulePath a path in while to locate the modules

     *    if the declaration is compiled

     * @return this builder

     */

        this.requires.add("requires " + requires + ";");

        this.modulePath.addAll(Arrays.asList(modulePath));

    /**

     * Adds a qualified "exports" directive to the declaration.

     * @param pkg the name of the package to be exported

     * @param module the name of the module to which it is to be exported

     * @return this builder

     */

        this.exports.add("exports " + pkg + " to " + module + ";");

        return this;

    /**

     * Adds an unqualified "exports" directive to the declaration.

     * @param pkg the name of the package to be exported

     * @param module the name of the module to which it is to be exported

     * @return this builder

     */

        this.exports.add("exports " + pkg + ";");

    /**

     * Adds a "uses" directive to the declaration.

     * @param service the name of the service type

     * @return this builder

     */

    public ModuleBuilder uses(String service) {

        this.uses.add("uses " + service + ";");

    /**

     * Adds a "provides" directive to the declaration.

     * @param service the name of the service type

     * @param implementation the name of the implementation type

     * @return this builder

     */

        this.provides.add("provides " + service + " with " + implementation + ";");

    /**

     * Adds type definitions to the module.

     * @param content a series of strings, each representing the content of

     *  a compilation unit to be included with the module

     * @return this builder

     */

    /**

     * Writes the module declaration and associated additional compilation

     * units to a module directory within a given directory.

     * @param srcDir the directory in which a directory will be created

     *  to contain the source files for the module

     * @return the directory containing the source files for the module

     */

    public Path write(Path srcDir) throws IOException {

        Files.createDirectories(srcDir);

        StringBuilder sb = new StringBuilder();

        if (!comment.isEmpty()) {

            sb.append("/**\n").append(comment.replace("\n", " *")).append(" */\n");

        }

        sb.append("module ").append(name).append(" {");

        requires.forEach(r -> sb.append("    " + r + "\n"));

        exports.forEach(e -> sb.append("    " + e + "\n"));

        uses.forEach(u -> sb.append("    " + u + "\n"));

        provides.forEach(p -> sb.append("    " + p + "\n"));

        sb.append("}");

        sources.add(sb.toString());

        Path moduleSrc = srcDir.resolve(name);

    /**

     * Writes the source files for the module to an interim directory,

     * and then compiles them to a given directory.

     * @param modules the directory in which a directory will be created

     *    to contain the compiled class files for the module

     * @throws IOException if an error occurs while compiling the files

     */

    public void build(Path modules) throws IOException {

        build(Paths.get(modules + "Src"), modules);

    }

    /**

     * Writes the source files for the module to a specified directory,

     * and then compiles them to a given directory.

     * @param srcDir the directory in which a directory will be created

     *  to contain the source files for the module

     * @param modules the directory in which a directory will be created

     *    to contain the compiled class files for the module

     * @throws IOException if an error occurs while compiling the files

     */

    public void build(Path src, Path modules) throws IOException {

        Path moduleSrc = write(src);

        String mp = modulePath.stream()

                .map(Path::toString)

                .collect(Collectors.joining(File.pathSeparator));

                .outdir(Files.createDirectories(modules.resolve(name)))

                .options("-mp", mp)