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Commons Net example source code file (WindowSizeOptionHandler.java)

This example Commons Net source code file (WindowSizeOptionHandler.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

override, override, telnetoptionhandler, telnetoptionhandler, window_size, window_size, windowsizeoptionhandler, windowsizeoptionhandler

The Commons Net WindowSizeOptionHandler.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;

/***
 * Implements the telnet window size option RFC 1073.
 * <p>
 * @author Yuval Kashtan
 * @version $Id: WindowSizeOptionHandler.java 963157 2010-07-11 22:56:30Z sebb $
 * @since 2.0
 ***/
public class WindowSizeOptionHandler extends TelnetOptionHandler
{
    /***
     * Horizontal Size
     ***/
    private int m_nWidth = 80;

    /***
     * Vertical Size
     ***/
    private int m_nHeight = 24;

    /***
     * Window size option
     ***/
    protected static final int WINDOW_SIZE = 31;

    /***
     * Constructor for the WindowSizeOptionHandler. Allows defining desired
     * initial setting for local/remote activation of this option and
     * behaviour in case a local/remote activation request for this
     * option is received.
     * <p>
     * @param nWidth - Window width.
     * @param nHeight - Window Height
     * @param initlocal - if set to true, a WILL is sent upon connection.
     * @param initremote - if set to true, a DO is sent upon connection.
     * @param acceptlocal - if set to true, any DO request is accepted.
     * @param acceptremote - if set to true, any WILL request is accepted.
     ***/
    public WindowSizeOptionHandler(
        int nWidth,
        int nHeight,
        boolean initlocal,
        boolean initremote,
        boolean acceptlocal,
        boolean acceptremote
    ) {
        super (
            TelnetOption.WINDOW_SIZE,
            initlocal,
            initremote,
            acceptlocal,
            acceptremote
        );

        m_nWidth = nWidth;
        m_nHeight = nHeight;
    }

    /***
     * Constructor for the WindowSizeOptionHandler. Initial and accept
     * behaviour flags are set to false
     * <p>
     * @param nWidth - Window width.
     * @param nHeight - Window Height
     ***/
    public WindowSizeOptionHandler(
        int nWidth,
        int nHeight
    ) {
        super (
            TelnetOption.WINDOW_SIZE,
            false,
            false,
            false,
            false
        );

        m_nWidth = nWidth;
        m_nHeight = nHeight;
    }

    /***
     * Implements the abstract method of TelnetOptionHandler.
     * <p>
     * @param suboptionData - the sequence received, whithout IAC SB & IAC SE
     * @param suboptionLength - the length of data in suboption_data
     * <p>
     * @return terminal type information
     ***/
    @Override
    public int[] answerSubnegotiation(int suboptionData[], int suboptionLength)
    {
        return null;
    }

    /***
     * Implements the abstract method of TelnetOptionHandler.
     * This will send the client Height and Width to the server.
     * <p>
     * @return array to send to remote system
     ***/
    @Override
    public int[] startSubnegotiationLocal()
    {
        int nCompoundWindowSize = m_nWidth * 0x10000 + m_nHeight;
        int nResponseSize = 5;
        int nIndex;
        int nShift;
        int nTurnedOnBits;

        if ((m_nWidth % 0x100) == 0xFF) {
            nResponseSize += 1;
        }

        if ((m_nWidth / 0x100) == 0xFF) {
            nResponseSize += 1;
        }

        if ((m_nHeight % 0x100) == 0xFF) {
            nResponseSize += 1;
        }

        if ((m_nHeight / 0x100) == 0xFF) {
            nResponseSize += 1;
        }

        //
        // allocate response array
        //
        int response[] = new int[nResponseSize];

        //
        // Build response array.
        // ---------------------
        // 1. put option name.
        // 2. loop through Window size and fill the values,
        // 3.    duplicate 'ff' if needed.
        //

        response[0] = WINDOW_SIZE;                          // 1 //

        for (                                               // 2 //
            nIndex=1, nShift = 24;
            nIndex < nResponseSize;
            nIndex++, nShift -=8
        ) {
            nTurnedOnBits = 0xFF;
            nTurnedOnBits <<= nShift;
            response[nIndex] = (nCompoundWindowSize & nTurnedOnBits) >>> nShift;

            if (response[nIndex] == 0xff) {                 // 3 //
                nIndex++;
                response[nIndex] = 0xff;
            }
        }

        return response;
    }

    /***
     * Implements the abstract method of TelnetOptionHandler.
     * <p>
     * @return always null (no response to subnegotiation)
     ***/
    @Override
    public int[] startSubnegotiationRemote()
    {
        return null;
    }
}

Other Commons Net examples (source code examples)

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