IOUtil.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.net.examples.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.net.io.Util;
import org.apache.commons.net.util.NetConstants;

/**
 * This is a utility class providing a reader/writer capability required by the weatherTelnet, rexec, rshell, and rlogin example programs. The only point of the
 * class is to hold the static method readWrite which spawns a reader thread and a writer thread. The reader thread reads from a local input source (presumably
 * stdin) and writes the data to a remote output destination. The writer thread reads from a remote input source and writes to a local output destination. The
 * threads terminate when the remote input source closes.
 */

public final class IOUtil {

    public static void readWrite(final InputStream remoteInput, final OutputStream remoteOutput, final InputStream localInput, final OutputStream localOutput) {
        final Thread reader;
        final Thread writer;

        reader = new Thread(() -> {
            int ch;

            try {
                while (!Thread.interrupted() && (ch = localInput.read()) != NetConstants.EOS) {
                    remoteOutput.write(ch);
                    remoteOutput.flush();
                }
            } catch (final IOException e) {
                // e.printStackTrace();
            }
        });

        writer = new Thread(() -> {
            try {
                Util.copyStream(remoteInput, localOutput);
            } catch (final IOException e) {
                e.printStackTrace();
                System.exit(1);
            }
        });

        writer.setPriority(Thread.currentThread().getPriority() + 1);

        writer.start();
        reader.setDaemon(true);
        reader.start();

        try {
            writer.join();
            reader.interrupt();
        } catch (final InterruptedException e) {
            // Ignored
        }
    }

}