/*

 * Copyright (c) 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.

 *

 * 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.

 */

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

/**

 * Handles the process output (either stdin or stdout)

 * passing the lines to a listener

 */

public class StreamHandler implements Runnable {

    public interface Listener {

        /**

         * Called when a line has been read from the process output stream

         * @param handler this StreamHandler

         * @param s the line

         */

        void onStringRead(StreamHandler handler, String s);

    }

    private final ExecutorService executor;

    private final InputStream is;

    private final Listener listener;

    /**

     * @param is input stream to read from

     * @param listener listener to pass the read lines to

     * @throws IOException

     */

    public StreamHandler(InputStream is, Listener listener) throws IOException {

        this.is = is;

        this.listener = listener;

        executor = Executors.newSingleThreadExecutor();

    }

    /**

     * Starts asynchronous reading

     */

    public void start() {

        executor.submit(this);

    }

    @Override

    public void run() {

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(is));

            String line;

            while ((line = br.readLine()) != null) {

                listener.onStringRead(this, line);

            }

        } catch (Exception x) {

            throw new RuntimeException(x);

        }

    }

}