CopyReader.java

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/*
 * Gridarta MMORPG map editor for Crossfire, Daimonin and similar games.
 * Copyright (C) 2000-2015 The Gridarta Developers.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package net.sf.gridarta.utils;

import java.io.CharArrayWriter;
import java.io.IOException;
import java.io.Reader;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class CopyReader {

    @NotNull
    private final Reader reader;

    @NotNull
    private final Object sync = new Object();

    @NotNull
    private final CharArrayWriter charArrayWriter = new CharArrayWriter();

    private boolean stopped;

    @Nullable
    private String failure;

    @NotNull
    private final Runnable runnable = new Runnable() {

        @Override
        public void run() {
            final char[] buf = new char[1024];
            while (!Thread.currentThread().isInterrupted()) {
                try {
                    final int len = reader.read(buf);
                    if (len == -1) {
                        break;
                    }
                    synchronized (sync) {
                        if (stopped) {
                            break;
                        }
                        charArrayWriter.write(buf, 0, len);
                    }
                } catch (final IOException ex) {
                    setFailure(ex.getMessage());
                }
            }
        }

    };

    @NotNull
    private final Thread thread = new Thread(runnable);

    public CopyReader(@NotNull final Reader reader) {
        this.reader = reader;
    }

    public void start() {
        thread.start();
    }

    public void stop() {
        thread.interrupt();
    }

    @SuppressWarnings("NullableProblems")
    private void setFailure(@NotNull final String failure) {
        synchronized (sync) {
            stopped = true;
            if (this.failure == null) {
                this.failure = failure;
            }
        }
    }

    @Nullable
    public String getFailure() {
        synchronized (sync) {
            stopped = true;
            thread.interrupt();
            return failure;
        }
    }

    @NotNull
    public String getOutput() {
        synchronized (sync) {
            stopped = true;
            thread.interrupt();
            return charArrayWriter.toString();
        }
    }

    public void join() throws InterruptedException {
        thread.join();
    }

}