xref: /openjdk10/langtools/src/jdk.javadoc/share/classes/com/sun/javadoc/Doclet.java

/*
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 * 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.
 *
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package com.sun.javadoc;

/**
 * This is an example of a starting class for a doclet,
 * showing the entry-point methods.  A starting class must
 * import com.sun.javadoc.* and implement the
 * {@code start(RootDoc)} method, as described in the
 * <a href="package-summary.html#package_description">package
 * description</a>.  If the doclet takes command line options,
 * it must also implement {@code optionLength} and
 * {@code validOptions}.
 *
 * <p> A doclet supporting the language features added since 1.1
 * (such as generics and annotations) should indicate this
 * by implementing {@code languageVersion}.  In the absence of
 * this the doclet should not invoke any of the Doclet API methods
 * added since 1.5, and
 * the results of several other methods are modified so as
 * to conceal the new constructs (such as type parameters) from
 * the doclet.
 *
 * <p> To start the doclet, pass
 * {@code -doclet} followed by the fully-qualified
 * name of the starting class on the javadoc tool command line.
 */
public abstract class Doclet {

    /**
     * Generate documentation here.
     * This method is required for all doclets.
     *
     * @param root Supply the RootDoc to the method.
     * @return true on success.
     */
    public static boolean start(RootDoc root) {
        return true;
    }

    /**
     * Check for doclet-added options.  Returns the number of
     * arguments you must specify on the command line for the
     * given option.  For example, "-d docs" would return 2.
     * <P>
     * This method is required if the doclet contains any options.
     * If this method is missing, Javadoc will print an invalid flag
     * error for every option.
     *
     * @param option the option for which the number of arguements is returned.
     * @return number of arguments on the command line for an option
     *         including the option name itself.  Zero return means
     *         option not known.  Negative value means error occurred.
     */
    public static int optionLength(String option) {
        return 0;  // default is option unknown
    }

    /**
     * Check that options have the correct arguments.
     * <P>
     * This method is not required, but is recommended,
     * as every option will be considered valid if this method
     * is not present.  It will default gracefully (to true)
     * if absent.
     * <P>
     * Printing option related error messages (using the provided
     * DocErrorReporter) is the responsibility of this method.
     *
     * @param options Supply valid options as an array of Strings.
     * @param reporter The DocErrorReporter responsible for these options.
     * @return true if the options are valid.
     */
    public static boolean validOptions(String options[][],
                                       DocErrorReporter reporter) {
        return true;  // default is options are valid
    }

    /**
     * Return the version of the Java Programming Language supported
     * by this doclet.
     * <p>
     * This method is required by any doclet supporting a language version
     * newer than 1.1.
     *
     * @return  the language version supported by this doclet.
     * @since 1.5
     */
    public static LanguageVersion languageVersion() {
        return LanguageVersion.JAVA_1_1;
    }
}