Ant example source code file (TelnetTask.java)

This example Ant source code file (TelnetTask.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 - Ant tags/keywords

anttelnetclient, buildexception, buildexception, integer, io, no, specified, string, string, stringbuffer, telnetread, telnetread, telnetsubtask, telnetsubtask, util, vector

The TelnetTask.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.tools.ant.taskdefs.optional.net;

import org.apache.commons.net.telnet.TelnetClient;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Calendar;
import java.util.Enumeration;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;

/**
 * Automates the telnet protocol.
 *
 */

public class TelnetTask extends Task {
    /**
     *  The userid to login with, if automated login is used
     */
    private String userid  = null;

    /**
     *  The password to login with, if automated login is used
     */
    private String password = null;

    /**
     *  The server to connect to.
     */
    private String server  = null;

    /**
     *  The tcp port to connect to.
     */
    private int port = 23;

    /**
     *  The list of read/write commands for this session
     */
    private Vector telnetTasks = new Vector();

    /**
     *  If true, adds a CR to beginning of login script
     */
    private boolean addCarriageReturn = false;

    /**
     *  Default time allowed for waiting for a valid response
     *  for all child reads.  A value of 0 means no limit.
     */
    private Integer defaultTimeout = null;

    /**
     *  Verify that all parameters are included.
     *  Connect and possibly login
     *  Iterate through the list of Reads and writes
     * @throws BuildException on error
     */
    public void execute() throws BuildException {
       /**  A server name is required to continue */
       if (server == null) {
           throw new BuildException("No Server Specified");
       }
       /**  A userid and password must appear together
        *   if they appear.  They are not required.
        */
       if (userid == null && password != null) {
           throw new BuildException("No Userid Specified");
       }
       if (password == null && userid != null) {
           throw new BuildException("No Password Specified");
       }

       /**  Create the telnet client object */
       AntTelnetClient telnet = null;
       try {
           telnet = new AntTelnetClient();
           try {
               telnet.connect(server, port);
           } catch (IOException e) {
               throw new BuildException("Can't connect to " + server);
           }
           /**  Login if userid and password were specified */
           if (userid != null && password != null) {
               login(telnet);
           }
           /**  Process each sub command */
           Enumeration tasksToRun = telnetTasks.elements();
           while (tasksToRun != null && tasksToRun.hasMoreElements()) {
               TelnetSubTask task = (TelnetSubTask) tasksToRun.nextElement();
               if (task instanceof TelnetRead && defaultTimeout != null) {
                   ((TelnetRead) task).setDefaultTimeout(defaultTimeout);
               }
               task.execute(telnet);
           }
       } finally {
           if (telnet != null && telnet.isConnected()) {
               try {
                   telnet.disconnect();
               } catch (IOException e) {
                   throw new BuildException("Error disconnecting from "
                                            + server);
               }
           }
       }
    }

    /**
     *  Process a 'typical' login.  If it differs, use the read
     *  and write tasks explicitely
     */
    private void login(AntTelnetClient telnet) {
       if (addCarriageReturn) {
          telnet.sendString("\n", true);
       }
       telnet.waitForString("ogin:");
       telnet.sendString(userid, true);
       telnet.waitForString("assword:");
       telnet.sendString(password, false);
    }

    /**
     * Set the the login id to use on the server;
     * required if <tt>password is set.
     * @param u a <code>String value
     */
    public void setUserid(String u) {
        this.userid = u;
    }

    /**
     *  Set the the login password to use
     * required if <tt>userid is set.
     * @param p a <code>String value
     */
    public void setPassword(String p) {
        this.password = p;
    }

    /**
     *  Set the hostname or address of the remote server.
     * @param m a <code>String value
     */
    public void setServer(String m) {
        this.server = m;
    }

    /**
     *  Set the tcp port to connect to; default is 23.
     * @param p an <code>int value
     */
    public void setPort(int p) {
        this.port = p;
    }

    /**
     *  send a carriage return after connecting; optional, defaults to false.
     * @param b a <code>boolean value
     */
    public void setInitialCR(boolean b) {
       this.addCarriageReturn = b;
    }

    /**
     * set a default timeout in seconds to wait for a response,
     * zero means forever (the default)
     * @param i an <code>Integer value
     */
    public void setTimeout(Integer i) {
       this.defaultTimeout = i;
    }

    /**
     *  A string to wait for from the server.
     *  A subTask <read> tag was found.  Create the object,
     *  Save it in our list, and return it.
     * @return a read telnet sub task
     */

    public TelnetSubTask createRead() {
        TelnetSubTask task = (TelnetSubTask) new TelnetRead();
        telnetTasks.addElement(task);
        return task;
    }

    /**
     *  Add text to send to the server
     *  A subTask <write> tag was found.  Create the object,
     *  Save it in our list, and return it.
     * @return a write telnet sub task
     */
    public TelnetSubTask createWrite() {
        TelnetSubTask task = (TelnetSubTask) new TelnetWrite();
        telnetTasks.addElement(task);
        return task;
    }

    /**
     *  This class is the parent of the Read and Write tasks.
     *  It handles the common attributes for both.
     */
    public class TelnetSubTask {
        // CheckStyle:VisibilityModifier OFF - bc
        protected String taskString = "";
        // CheckStyle:VisibilityModifier ON
        /**
         * Execute the subtask.
         * @param telnet the client
         * @throws BuildException always as it is not allowed to instantiate this object
         */
        public void execute(AntTelnetClient telnet)
                throws BuildException {
            throw new BuildException("Shouldn't be able instantiate a SubTask directly");
        }

        /**
         *  the message as nested text
         * @param s the nested text
         */
        public void addText(String s) {
            setString(getProject().replaceProperties(s));
        }

        /**
         * the message as an attribute
         * @param s a <code>String value
         */
        public void setString(String s) {
           taskString += s;
        }
    }

    /**
     *  Sends text to the connected server
     */
    public class TelnetWrite extends TelnetSubTask {
        private boolean echoString = true;
        /**
         * Execute the write task.
         * @param telnet the task to use
         * @throws BuildException on error
         */
        public void execute(AntTelnetClient telnet)
               throws BuildException {
           telnet.sendString(taskString, echoString);
        }

        /**
         * Whether or not the message should be echoed to the log.
         * Defaults to <code>true.
         * @param b a <code>boolean value
         */
        public void setEcho(boolean b) {
           echoString = b;
        }
    }

    /**
     *  Reads the output from the connected server
     *  until the required string is found or we time out.
     */
    public class TelnetRead extends TelnetSubTask {
        private Integer timeout = null;
        /**
         * Execute the read task.
         * @param telnet the task to use
         * @throws BuildException on error
         */
        public void execute(AntTelnetClient telnet)
               throws BuildException {
            telnet.waitForString(taskString, timeout);
        }
        /**
         *  a timeout value that overrides any task wide timeout.
         * @param i an <code>Integer value
         */
        public void setTimeout(Integer i) {
           this.timeout = i;
        }

        /**
         * Sets the default timeout if none has been set already
         * @param defaultTimeout an <code>Integer value
         * @ant.attribute ignore="true"
         */
        public void setDefaultTimeout(Integer defaultTimeout) {
           if (timeout == null) {
              timeout = defaultTimeout;
           }
        }
    }

    /**
     *  This class handles the abstraction of the telnet protocol.
     *  Currently it is a wrapper around <a
     *  href="http://jakarta.apache.org/commons/net/index.html">Jakarta
     *  Commons Net</a>.
     */
    public class AntTelnetClient extends TelnetClient {
        /**
         * Read from the telnet session until the string we are
         * waiting for is found
         * @param s The string to wait on
         */
        public void waitForString(String s) {
            waitForString(s, null);
        }

        /**
         * Read from the telnet session until the string we are
         * waiting for is found or the timeout has been reached
         * @param s The string to wait on
         * @param timeout The maximum number of seconds to wait
         */
        public void waitForString(String s, Integer timeout) {
            InputStream is = this.getInputStream();
            try {
                StringBuffer sb = new StringBuffer();
                if (timeout == null || timeout.intValue() == 0) {
                    while (sb.toString().indexOf(s) == -1) {
                        sb.append((char) is.read());
                    }
                } else {
                    Calendar endTime = Calendar.getInstance();
                    endTime.add(Calendar.SECOND, timeout.intValue());
                    while (sb.toString().indexOf(s) == -1) {
                        while (Calendar.getInstance().before(endTime)
                               && is.available() == 0) {
                            Thread.sleep(250);
                        }
                        if (is.available() == 0) {
                            log("Read before running into timeout: "
                                + sb.toString(), Project.MSG_DEBUG);
                            throw new BuildException(
                                "Response timed-out waiting for \"" + s + '\"',
                                getLocation());
                        }
                        sb.append((char) is.read());
                    }
                }
                log(sb.toString(), Project.MSG_INFO);
            } catch (BuildException be) {
                throw be;
            } catch (Exception e) {
                throw new BuildException(e, getLocation());
            }
        }

        /**
         * Write this string to the telnet session.
         * @param s          the string to write
         * @param echoString if true log the string sent
         */
        public void sendString(String s, boolean echoString) {
            OutputStream os = this.getOutputStream();
            try {
                os.write((s + "\n").getBytes());
                if (echoString) {
                    log(s, Project.MSG_INFO);
                }
                os.flush();
            } catch (Exception e) {
                throw new BuildException(e, getLocation());
            }
        }
    }
}