/*

 * Copyright 2005-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.tools.javac.util;

import java.util.HashSet;

import java.util.Set;

import javax.tools.JavaFileObject;

import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;

/**

 * A handler to process mandatory warnings, setting up a deferred diagnostic

 * to be printed at the end of the compilation if some warnings get suppressed

 * because too many warnings have already been generated.

 *

 * Note that the SuppressWarnings annotation can be used to suppress warnings

 * about conditions that would otherwise merit a warning. Such processing

 * is done when the condition is detected, and in those cases, no call is

 * made on any API to generate a warning at all. In consequence, this handler only

 * gets to handle those warnings that JLS says must be generated.

 *

 *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If

 *  you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class MandatoryWarningHandler {

    /**

     * The kinds of different deferred diagnostics that might be generated

     * if a mandatory warning is suppressed because too many warnings have

     * already been output.

     *

     * The parameter is a fragment used to build an I18N message key for Log.

     */

    private enum DeferredDiagnosticKind {

        /**

         * This kind is used when a single specific file is found to have warnings

         * and no similar warnings have already been given.

         * It generates a message like:

         *      FILE has ISSUES

         */

        IN_FILE(".filename"),

        /**

         * This kind is used when a single specific file is found to have warnings

         * and when similar warnings have already been reported for the file.

         * It generates a message like:

         *      FILE has additional ISSUES

         */

        ADDITIONAL_IN_FILE(".filename.additional"),

        /**

         * This kind is used when multiple files have been found to have warnings,

         * and none of them have had any similar warnings.

         * It generates a message like:

         *      Some files have ISSUES

         */

        IN_FILES(".plural"),

        /**

         * This kind is used when multiple files have been found to have warnings,

         * and some of them have had already had specific similar warnings.

         * It generates a message like:

         *      Some files have additional ISSUES

         */

        ADDITIONAL_IN_FILES(".plural.additional");

        DeferredDiagnosticKind(String v) { value = v; }

        String getKey(String prefix) { return prefix + value; }

        private String value;

    }

    /**

     * Create a handler for mandatory warnings.

     * @param log     The log on which to generate any diagnostics

     * @param verbose Specify whether or not detailed messages about

     *                individual instances should be given, or whether an aggregate

     *                message should be generated at the end of the compilation.

     *                Typically set via  -Xlint:option.

     * @param prefix  A common prefix for the set of message keys for

     *                the messages that may be generated.

     */

    public MandatoryWarningHandler(Log log, boolean verbose, String prefix) {

        this.log = log;

        this.verbose = verbose;

        this.prefix = prefix;

    }

    /**

     * Report a mandatory warning.

     */

    public void report(DiagnosticPosition pos, String msg, Object... args) {

        JavaFileObject currentSource = log.currentSource();

        if (verbose) {

            if (sourcesWithReportedWarnings == null)

                sourcesWithReportedWarnings = new HashSet<JavaFileObject>();

            if (log.nwarnings < log.MaxWarnings) {

                // generate message and remember the source file

                log.mandatoryWarning(pos, msg, args);

                sourcesWithReportedWarnings.add(currentSource);

            } else if (deferredDiagnosticKind == null) {

                // set up deferred message

                if (sourcesWithReportedWarnings.contains(currentSource)) {

                    // more errors in a file that already has reported warnings

                    deferredDiagnosticKind = DeferredDiagnosticKind.ADDITIONAL_IN_FILE;

                } else {

                    // warnings in a new source file

                    deferredDiagnosticKind = DeferredDiagnosticKind.IN_FILE;

                }

                deferredDiagnosticSource = currentSource;

                deferredDiagnosticArg = currentSource;

            } else if ((deferredDiagnosticKind == DeferredDiagnosticKind.IN_FILE

                        || deferredDiagnosticKind == DeferredDiagnosticKind.ADDITIONAL_IN_FILE)

                       && !equal(deferredDiagnosticSource, currentSource)) {

                // additional errors in more than one source file

                deferredDiagnosticKind = DeferredDiagnosticKind.ADDITIONAL_IN_FILES;

                deferredDiagnosticArg = null;

            }

        } else {

            if (deferredDiagnosticKind == null) {

                // warnings in a single source

                deferredDiagnosticKind = DeferredDiagnosticKind.IN_FILE;

                deferredDiagnosticSource = currentSource;

                deferredDiagnosticArg = currentSource;

            }  else if (deferredDiagnosticKind == DeferredDiagnosticKind.IN_FILE &&

                        !equal(deferredDiagnosticSource, currentSource)) {

                // warnings in multiple source files

                deferredDiagnosticKind = DeferredDiagnosticKind.IN_FILES;

                deferredDiagnosticArg = null;

            }

        }

    }

    /**

     * Report any diagnostic that might have been deferred by previous calls of report().

     */

    public void reportDeferredDiagnostic() {

        if (deferredDiagnosticKind != null) {

            if (deferredDiagnosticArg == null)

                log.mandatoryNote(deferredDiagnosticSource, deferredDiagnosticKind.getKey(prefix));

            else

                log.mandatoryNote(deferredDiagnosticSource, deferredDiagnosticKind.getKey(prefix), deferredDiagnosticArg);

            if (!verbose)

                log.mandatoryNote(deferredDiagnosticSource, prefix + ".recompile");

        }

    }

    /**

     * Check two objects, each possibly null, are either both null or are equal.

     */

    private static boolean equal(Object o1, Object o2) {

        return ((o1 == null || o2 == null) ? (o1 == o2) : o1.equals(o2));

    }

    /**

     * The log to which to report warnings.

     */

    private Log log;

    /**

     * Whether or not to report individual warnings, or simply to report a

     * single aggregate warning at the end of the compilation.

     */

    private boolean verbose;

    /**

     * The common prefix for all I18N message keys generated by this handler.

     */

    private String prefix;

    /**

     * A set containing the names of the source files for which specific

     * warnings have been generated -- i.e. in verbose mode.  If a source name

     * appears in this list, then deferred diagnostics will be phrased to

     * include "additionally"...

     */

    private Set<JavaFileObject> sourcesWithReportedWarnings;

    /**

     * A variable indicating the latest best guess at what the final

     * deferred diagnostic will be. Initially as specific and helpful

     * as possible, as more warnings are reported, the scope of the

     * diagnostic will be broadened.

     */

    private DeferredDiagnosticKind deferredDiagnosticKind;

    /**

     * If deferredDiagnosticKind is IN_FILE or ADDITIONAL_IN_FILE, this variable

     * gives the value of log.currentSource() for the file in question.

     */

    private JavaFileObject deferredDiagnosticSource;

    /**

     * An optional argument to be used when constructing the

     * deferred diagnostic message, based on deferredDiagnosticKind.

     * This variable should normally be set/updated whenever

     * deferredDiagnosticKind is updated.

     */

    private Object deferredDiagnosticArg;

}