/*
 * Copyright (c) 2014, 2016, 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
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package com.sun.tools.sjavac.comp;

import com.sun.tools.javac.main.Main.Result;
import com.sun.tools.sjavac.Log;
import com.sun.tools.sjavac.server.Sjavac;

import java.util.Objects;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

An sjavac implementation that limits the number of concurrent calls by
wrapping invocations in Callables and delegating them to a FixedThreadPool.
 
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.
/**
 * An sjavac implementation that limits the number of concurrent calls by
 * wrapping invocations in Callables and delegating them to a FixedThreadPool.
 *
 *  <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 PooledSjavac implements Sjavac {

    final Sjavac delegate;
    final ExecutorService pool;

    public PooledSjavac(Sjavac delegate, int poolsize) {
        Objects.requireNonNull(delegate);
        this.delegate = delegate;
        pool = Executors.newFixedThreadPool(poolsize);
    }

    @Override
    public Result compile(String[] args) {
        Log log = Log.get();
        try {
            return pool.submit(() -> {
                Log.setLogForCurrentThread(log);
                return delegate.compile(args);
            }).get();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("Error during compile", e);
        }
    }

    @Override
    public void shutdown() {
        Log.debug("Shutting down PooledSjavac");
        pool.shutdown(); // Disable new tasks from being submitted
        try {
            // Wait a while for existing tasks to terminate
            if (!pool.awaitTermination(60, TimeUnit.SECONDS)) {
                pool.shutdownNow(); // Cancel currently executing tasks
                // Wait a while for tasks to respond to being cancelled
                if (!pool.awaitTermination(60, TimeUnit.SECONDS))
                    Log.error("ThreadPool did not terminate");
            }
        } catch (InterruptedException ie) {
          // (Re-)Cancel if current thread also interrupted
          pool.shutdownNow();
          // Preserve interrupt status
          Thread.currentThread().interrupt();
        }

        delegate.shutdown();
    }

}