/*

 * Copyright (c) 2011, 2013, Oracle and/or its affiliates. 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.  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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.javac.code;

import java.util.HashMap;

import java.util.Map;

import com.sun.tools.javac.tree.EndPosTable;

import com.sun.tools.javac.tree.JCTree;

import com.sun.tools.javac.util.Assert;

import com.sun.tools.javac.util.Context;

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

import com.sun.tools.javac.util.ListBuffer;

/**

 *

 * <p><b>This is NOT part of any supported API.

 * 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 DeferredLintHandler {

    protected static final Context.Key<DeferredLintHandler> deferredLintHandlerKey =

        new Context.Key<DeferredLintHandler>();

    public static DeferredLintHandler instance(Context context) {

        DeferredLintHandler instance = context.get(deferredLintHandlerKey);

        if (instance == null)

            instance = new DeferredLintHandler(context);

        return instance;

    }

    protected DeferredLintHandler(Context context) {

        context.put(deferredLintHandlerKey, this);

        this.currentPos = IMMEDIATE_POSITION;

    }

    /**An interface for deferred lint reporting - loggers passed to

     * {@link #report(LintLogger) } will be called when

     * {@link #flush(DiagnosticPosition) } is invoked.

     */

    public interface LintLogger {

        void report();

    }

    private DiagnosticPosition currentPos;

    private Map<DiagnosticPosition, ListBuffer<LintLogger>> loggersQueue = new HashMap<DiagnosticPosition, ListBuffer<LintLogger>>();

    /**Associate the given logger with the current position as set by {@link #setPos(DiagnosticPosition) }.

     * Will be invoked when {@link #flush(DiagnosticPosition) } will be invoked with the same position.

     * <br>

     * Will invoke the logger synchronously if {@link #immediate() } was called

     * instead of {@link #setPos(DiagnosticPosition) }.

     */

    public void report(LintLogger logger) {

        if (currentPos == IMMEDIATE_POSITION) {

            logger.report();

        } else {

            ListBuffer<LintLogger> loggers = loggersQueue.get(currentPos);

            if (loggers == null) {

            }

            loggers.append(logger);

        }

    }

    /**Invoke all {@link LintLogger}s that were associated with the provided {@code pos}.

     */

    public void flush(DiagnosticPosition pos) {

        ListBuffer<LintLogger> loggers = loggersQueue.get(pos);

        if (loggers != null) {

            for (LintLogger lintLogger : loggers) {

                lintLogger.report();

            }

            loggersQueue.remove(pos);

        }

    }

    /**Sets the current position to the provided {@code currentPos}. {@link LintLogger}s

     * passed to subsequent invocations of {@link #report(LintLogger) } will be associated

     * with the given position.

     */

    public DiagnosticPosition setPos(DiagnosticPosition currentPos) {

        DiagnosticPosition prevPosition = this.currentPos;

        this.currentPos = currentPos;

        return prevPosition;

    }

    /**{@link LintLogger}s passed to subsequent invocations of

     * {@link #report(LintLogger) } will be invoked immediately.

     */

    public DiagnosticPosition immediate() {

        return setPos(IMMEDIATE_POSITION);

    }

    private static final DiagnosticPosition IMMEDIATE_POSITION = new DiagnosticPosition() {

        @Override

        public JCTree getTree() {

            Assert.error();

            return null;

        }

        @Override

        public int getStartPosition() {

            Assert.error();

            return -1;

        }

        @Override

        public int getPreferredPosition() {

            Assert.error();

            return -1;

        }

        @Override

        public int getEndPosition(EndPosTable endPosTable) {

            Assert.error();

            return -1;

        }

    };

}