persistentinputstream.java

sifi-0.1.6.tar.gz 出自http://www.ifi.unizh.ch/ikm/SINUS/firewall/ 一个linux的防火墙工具。

/*
 * Gary Cornell and Cay S. Horstmann, Core Java (Book/CD-ROM)
 * Published By SunSoft Press/Prentice-Hall
 * Copyright (C) 1996 Sun Microsystems Inc.
 * All Rights Reserved. ISBN 0-13-565755-5
 *
 * Permission to use, copy, modify, and distribute this 
 * software and its documentation for NON-COMMERCIAL purposes
 * and without fee is hereby granted provided that this 
 * copyright notice appears in all copies. 
 * 
 * THE AUTHORS AND PUBLISHER MAKE NO REPRESENTATIONS OR 
 * WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE, EITHER 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE AUTHORS
 * AND PUBLISHER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED 
 * BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING 
 * THIS SOFTWARE OR ITS DERIVATIVES.
 */
 
/**
 * @version 1.00 07 Feb 1996 
 * @author Cay Horstmann, modified by Roland E. Schmid
 */

package sfclasses;

import java.io.*;
import java.util.*;
import corejava.*;

/**
 * This stream is used to restore data from a persistent state.
 * Normally the methods are called from the read() method defined
 * in the Persistent interface. <br>
 * When you want to start the restore process, you have to create
 * a new PersistentInputStream passing the data input stream as
 * parameter. Then call the appropriate method to restore the object
 * you are using as starting point (e.g. readPersistent). Any objects
 * contained in this object are automatically restored (recursively).
 */
public class PersistentInputStream extends PushbackInputStream
{  /** 
    * Initialize the stream using fs as data source.
    * @param fs data input stream
    */
   public PersistentInputStream(InputStream fs)
   {   super(fs);
   }
   
   /**
    * Read object
    * @param skip Identification string, must end with a comma!
    * @return Object read, must be typecast to assign to object variable.
    */
   public Persistent readPersistent(String skip)
      throws java.io.IOException
   {  
		skipString(skip);
      int ch;
      do 
        ch = read();
      while (ch==10 || ch==','); // skip LF and comma
      if (ch == '0')
			return null;
      unread(ch);
      int n;
      if (Character.isDigit((char)ch))
      {  n = Format.atoi(getToken());
         return find(n); 
      }
      String className = getToken();
      skipString("[");
      Persistent x; 
      try
      {  Class cl = Class.forName(className);
         Object ob = cl.newInstance(); 
         x = (Persistent)ob;
      } catch(Exception ex)
      {  throw new java.io.IOException(ex.toString());
      }         
      x.read(this);
      skipString("]");
      n = Format.atoi(getToken());      
      add(n, x);
      return x;
   }

   /**
    * Read integer.
    * @param skip Identification string, must end with a comma!
    * @return Value read
    */
   public int readInt(String skip) throws java.io.IOException
   {  skipString(skip);
      String s = getToken();
      return Format.atoi(s);
   }

   /**
    * Read boolean.
    * @param skip Identification string, must end with a comma!
    * @return Value read
    */
   public boolean readBoolean(String skip) throws java.io.IOException
   {  skipString(skip);
      String s = getToken();
      if (s.equals("true"))
        return true;
      else
        return false;
   }

   /**
    * Read double.
    * @param skip Identification string, must end with a comma!
    * @return Value read
    */
   public double readDouble(String skip)
      throws java.io.IOException
   {  skipString(skip);
      String s = getToken();
      return Format.atof(s);
   }

   /**
    * Read string.
    * @param skip Identification string, must end with a comma!
    * @return Value read
    */
   public String readString(String skip)
      throws java.io.IOException
   {  skipString(skip);
      skipWhite();
      int ch = read();
      if (ch == '0') return null;
      if (ch != '"') 
         throw new java.io.IOException("String expected");
      StringBuffer b = new StringBuffer(100);
      while (true)
      {  ch = read();
         if (ch == -1 || ch == '"') {
				 		ch = read();									// skip comma
						if (ch != ',')
							unread(ch);
            return new String(b);
					}
         if (ch == '\\')
            ch = read();
         b.append((char)ch);       
      }                  
   }
   
   /**
    * Read vector.
    * @param skip Identification string, must end with a comma!
    * @return Vector read
    */
   public Vector readPersistentVector(String skip) throws java.io.IOException
   {  skipString(skip);
      int ch;
      do 
        ch = read();
      while (ch==10); // skip LF
      if (ch == '0') return null;
      unread(ch);
			skipString("Vector[");
      int n = readInt("Size=");
      Vector v = new Vector(n);
      for (int i = 0; i < n; i++)
      {  Persistent x = readPersistent("Element=");
         v.addElement(x);
      }
      skipString("],");
      return v;
   }   
   
   /**
    * Skip given string. Called from the various read() methods.
    */
   public void skipString(String s) throws java.io.IOException      
   {  
		skipWhite();
      int i = 0;
      while (i < s.length())
      {  int ch;
         ch = read();
         if (ch != s.charAt(i))
            throw new java.io.IOException(s + " expected");
         i++;
      }            
   }         
   
   private String getToken() throws java.io.IOException
   {  skipWhite();
      StringBuffer b = new StringBuffer(100);
      while (true)
      {  int ch;
         ch = read();
         if (ch == -1 || Character.isWhitespace((char)ch) 
               || ch == ',' || ch == '[' || ch == ']')
         {  if (ch != ',')
				 			unread(ch);
            return new String(b);
         }
         if (ch == '\\')
            ch = read();
         b.append((char)ch);       
      }            
   }
      
   private void skipWhite() throws java.io.IOException
   {  boolean more = true;
      int ch;
      do
      {  ch = read();
      } while (ch != -1 && (Character.isWhitespace((char)ch) || ch==10));
      	unread(ch);
   }      
      
   private void add(int n, Persistent x)
   {  if (n > pmap.size()) pmap.setSize(n);
      pmap.setElementAt(x, n - 1);
   }
   
   private Persistent find(int n)
   {  if (n <= pmap.size())
         return (Persistent)pmap.elementAt(n - 1);
      else
         return null;
   }
   
   private Vector pmap = new Vector();
}