owfileinputstream.java

这是一个以JAVA编写的程序,本人还没有试过,是一个简单的温度控制系统

/*---------------------------------------------------------------------------
 * Copyright (C) 2001 Dallas Semiconductor Corporation, All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY,  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES
 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Except as contained in this notice, the name of Dallas Semiconductor
 * shall not be used except as stated in the Dallas Semiconductor
 * Branding Policy.
 *---------------------------------------------------------------------------
 */

package com.dalsemi.onewire.application.file;

import java.io.IOException;
import java.io.InputStream;
import com.dalsemi.onewire.container.OneWireContainer;

/**
 * A <code>OWFileInputStream</code> obtains input bytes
 * from a file in a 1-Wire Filesystem. What files
 * are available depends on the 1-Wire device.
 *
 * <p> Note that the 1-Wire File system can reside across multiple 1-Wire
 *  devices.  In this case only one of the devices need be supplied to the
 *  constructor.  Each device in a multi-device file system contains
 *  information to reacquire the entire list.
 *
 * <p>  File and directory <b> name </b> limitations
 * <ul>
 * <li> File/directory names limited to 4 characters not including extension
 * <li> File/directory names are not case sensitive and will be automatically
 *      changed to all-CAPS
 * <li> Only files can have extensions
 * <li> Extensions are numberical in the range 0 to 125
 * <li> Extensions 100 to 125 are special purpose and not yet implemented or allowed
 * <li> Files can have the read-only attribute
 * <li> Directories can have the hidden attribute
 * <li> It is recommended to limit directory depth to 10 levels to accomodate
 *      legacy implementations
 * </ul>
 *
 * <H3> Usage </H3>
 * <DL>
 * <DD> <H4> Example </H4>
 * Read from a 1-Wire file on device 'owd':
 * <PRE> <CODE>
 *   // get an input stream to the 1-Wire file
 *   OWFileInputStream instream = new OWFileInputStream(owd, "DEMO.0");
 *
 *   // read some data
 *   byte[] data = new byte[2000];
 *   int len = instream.read(data);
 *
 *   // close the stream to release system resources
 *   instream.close();
 *
 * </CODE> </PRE>
 *
 * @author  DS
 * @version 0.01, 1 June 2001
 * @see     com.dalsemi.onewire.application.file.OWFile
 * @see     com.dalsemi.onewire.application.file.OWFileDescriptor
 * @see     com.dalsemi.onewire.application.file.OWFileOutputStream
 */
public class OWFileInputStream
   extends InputStream
{

   //--------
   //-------- Variables
   //--------

   /**
    * File descriptor.
    */
   private OWFileDescriptor fd;

   //--------
   //-------- Constructors
   //--------

   /**
    * Creates a <code>FileInputStream</code> by
    * opening a connection to an actual file,
    * the file named by the path name <code>name</code>
    * in the Filesystem.  A new <code>OWFileDescriptor</code>
    * object is created to represent this file
    * connection.
    * <p>
    * First, if there is a security
    * manager, its <code>checkRead</code> method
    * is called with the <code>name</code> argument
    * as its argument.
    * <p>
    * If the named file does not exist, is a directory rather than a regular
    * file, or for some other reason cannot be opened for reading then a
    * <code>FileNotFoundException</code> is thrown.
    *
    * @param      owd    OneWireContainer that this Filesystem resides on
    * @param      name   the system-dependent file name.
    * @exception  FileNotFoundException  if the file does not exist,
    *                   is a directory rather than a regular file,
    *                   or for some other reason cannot be opened for
    *                   reading.
    */
   public OWFileInputStream(OneWireContainer owd, String name)
      throws OWFileNotFoundException
   {
      fd = new OWFileDescriptor(owd, name);

      // open the file
      try
      {
         fd.open();
      }
      catch (OWFileNotFoundException e)
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException(e.toString());
      }

      // make sure this is not directory
      if (!fd.isFile())
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException("Not a file");
      }
   }

   /**
    * Creates a <code>FileInputStream</code> by
    * opening a connection to an actual file,
    * the file named by the path name <code>name</code>
    * in the Filesystem.  A new <code>OWFileDescriptor</code>
    * object is created to represent this file
    * connection.
    * <p>
    * First, if there is a security
    * manager, its <code>checkRead</code> method
    * is called with the <code>name</code> argument
    * as its argument.
    * <p>
    * If the named file does not exist, is a directory rather than a regular
    * file, or for some other reason cannot be opened for reading then a
    * <code>FileNotFoundException</code> is thrown.
    *
    * @param      owd    array of OneWireContainers that this Filesystem resides on
    * @param      name   the system-dependent file name.
    * @exception  FileNotFoundException  if the file does not exist,
    *                   is a directory rather than a regular file,
    *                   or for some other reason cannot be opened for
    *                   reading.
    */
   public OWFileInputStream(OneWireContainer[] owd, String name)
      throws OWFileNotFoundException
   {
      fd = new OWFileDescriptor(owd, name);

      // open the file
      try
      {
         fd.open();
      }
      catch (OWFileNotFoundException e)
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException(e.toString());
      }

      // make sure this is not directory
      if (!fd.isFile())
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException("Not a file");
      }
   }

   /**
    * Creates a <code>OWFileInputStream</code> by
    * opening a connection to an actual file,
    * the file named by the <code>File</code>
    * object <code>file</code> in the Filesystem.
    * A new <code>OWFileDescriptor</code> object
    * is created to represent this file connection.
    * <p>
    * If the named file does not exist, is a directory rather than a regular
    * file, or for some other reason cannot be opened for reading then a
    * <code>FileNotFoundException</code> is thrown.
    *
    * @param      file   the file to be opened for reading.
    * @exception  FileNotFoundException  if the file does not exist,
    *                   is a directory rather than a regular file,
    *                   or for some other reason cannot be opened for
    *                   reading.
    * @see        com.dalsemi.onewire.application.file.OWFile#getPath()
    */
   public OWFileInputStream(OWFile file)
      throws OWFileNotFoundException
   {
      // get the file descriptor
      try
      {
         fd = file.getFD();
      }
      catch (IOException e)
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException(e.toString());
      }

      // open the file
      try
      {
         fd.open();
      }
      catch (OWFileNotFoundException e)
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException(e.toString());
      }

      // make sure it is not a directory
      if (!fd.isFile())
      {
         fd.free();
         fd = null;
         throw new OWFileNotFoundException("Not a file");
      }
   }

   /**
    * Creates a <code>OWFileInputStream</code> by using the file descriptor
    * <code>fdObj</code>, which represents an existing connection to an
    * actual file in the Filesystem.
    * <p>
    * If <code>fdObj</code> is null then a <code>NullPointerException</code>
    * is thrown.
    *
    * @param      fdObj   the file descriptor to be opened for reading.