/*
 * 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;

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.
/**
 *
 * <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<>();

    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 DeferredLintHandler.report(LintLogger) will be called when DeferredLintHandler.flush(DiagnosticPosition) is invoked. /**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<>();

    
Associate the given logger with the current position as set by setPos(DiagnosticPosition). Will be invoked when flush(DiagnosticPosition) will be invoked with the same position. 
 Will invoke the logger synchronously if immediate() was called instead of setPos(DiagnosticPosition). /**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) {
                loggersQueue.put(currentPos, loggers = new ListBuffer<>());
            }
            loggers.append(logger);
        }
    }

    
Invoke all LintLoggers that were associated with the provided pos. /**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 currentPos. LintLoggers passed to subsequent invocations of report(LintLogger) will be associated with the given position. /**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;
    }

    
LintLoggers passed to subsequent invocations of report(LintLogger) will be invoked immediately. /**{@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;
        }
    };
}