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Commons Net example source code file (TelnetOutputStream.java)

This example Commons Net source code file (TelnetOutputStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Net tags/keywords

ascii, ascii, cr, cr, crlf, io, ioexception, ioexception, nul, outputstream, override, override, rfc854, telnetclient, telnetoutputstream

The Commons Net TelnetOutputStream.java source code

/*
 * 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.telnet;

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

/**
 * Wraps an output stream.
 * <p>
 * In binary mode, the only conversion is to double IAC.
 * <p>
 * In ASCII mode, if convertCRtoCRLF is true, any CR is converted to CRLF.
 * IACs are doubled.
 * <p>
 ***/


final class TelnetOutputStream extends OutputStream
{
    private final TelnetClient __client;
    // TODO there does not appear to be any way to change this value - should it be a ctor parameter?
    private boolean __convertCRtoCRLF = true;
    private boolean __lastWasCR = false;

    TelnetOutputStream(TelnetClient client)
    {
        __client = client;
    }


    /***
     * Writes a byte to the stream.
     * <p>
     * @param ch The byte to write.
     * @exception IOException If an error occurs while writing to the underlying
     *            stream.
     ***/
    @Override
    public void write(int ch) throws IOException
    {

        synchronized (__client)
        {
            ch &= 0xff;

            if (__client._requestedWont(TelnetOption.BINARY)) // i.e. ASCII
            {
                if (__lastWasCR)
                {
                    if (__convertCRtoCRLF)
                    {
                        __client._sendByte('\n');
                        if (ch == '\n') // i.e. was CRLF anyway
                        {
                            __lastWasCR = false;
                            return ;
                        }
                    } // __convertCRtoCRLF
                    else if (ch != '\n')
                        __client._sendByte('\0'); // RFC854 requires CR NUL for bare CR
                }

                __lastWasCR = false;

                switch (ch)
                {
                case '\r':
                    __client._sendByte('\r');
                    __lastWasCR = true;
                    break;
                case TelnetCommand.IAC:
                    __client._sendByte(TelnetCommand.IAC);
                    __client._sendByte(TelnetCommand.IAC);
                    break;
                default:
                    __client._sendByte(ch);
                    break;
                }
            } // end ASCII
            else if (ch == TelnetCommand.IAC)
            {
                __client._sendByte(ch);
                __client._sendByte(TelnetCommand.IAC);
            }
            else
                __client._sendByte(ch);
        }
    }


    /***
     * Writes a byte array to the stream.
     * <p>
     * @param buffer  The byte array to write.
     * @exception IOException If an error occurs while writing to the underlying
     *            stream.
     ***/
    @Override
    public void write(byte buffer[]) throws IOException
    {
        write(buffer, 0, buffer.length);
    }


    /***
     * Writes a number of bytes from a byte array to the stream starting from
     * a given offset.
     * <p>
     * @param buffer  The byte array to write.
     * @param offset  The offset into the array at which to start copying data.
     * @param length  The number of bytes to write.
     * @exception IOException If an error occurs while writing to the underlying
     *            stream.
     ***/
    @Override
    public void write(byte buffer[], int offset, int length) throws IOException
    {
        synchronized (__client)
        {
            while (length-- > 0)
                write(buffer[offset++]);
        }
    }

    /*** Flushes the stream. ***/
    @Override
    public void flush() throws IOException
    {
        __client._flushOutputStream();
    }

    /*** Closes the stream. ***/
    @Override
    public void close() throws IOException
    {
        __client._closeOutputStream();
    }
}

Other Commons Net examples (source code examples)

Here is a short list of links related to this Commons Net TelnetOutputStream.java source code file:

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