/*
Research Project:   Graphical Database for Category Theory
                    J. Bradbury, Dr. R. Rosebrugh, I. Rutherford
                    Mount Allison University 2001
File:               GMLobject.java
                    (author: Larry Barowski, Auburn University, 10/25/96)
Description:	      A GML object that does nothing but create itself and write
                    itself.
*/

   import java.lang.String;
   import java.lang.Double;
   import java.util.Hashtable;
   import java.io.IOException;
   import java.lang.System;

   public class GMLobject
      {
      public static final int GMLinteger = 0;
      public static final int GMLreal = 1;
      public static final int GMLstring = 2;
      public static final int GMLlist = 3;
      public static final int GMLundefined = 4;
      public static final int GMLfile = 5;
   
      protected String key_;
      protected Object value_;
      protected GMLobject next_;
      protected int type_;
   
      // State of iterator.
      private GMLobject searchobj_ = null;
      private String searchkey_ = null;
      private int searchtype_;
   
   
      public GMLobject()
         {
         key_ = "undefined";
         value_ = null;
         next_ = null;
         type_ = GMLundefined;
         }
   
   
   
      public GMLobject(String key, int type)
         {
         key_ = key;
         type_ = type;
         value_ = null;
         next_ = null;
         }
   
   
   
   
   
      /** Create the object from a GMLlexer and key. A null key will cause
       *  a GMLfile object to be created.
      **/
      public GMLobject(GMLlexer lexer, String key) throws java.io.IOException,
      ParseError
         {
         next_ = null;
      
         key_ = key;
      
         int token;
      
      	// Parse the value.
         if(key != null)
            {
            token = lexer.nextToken();
            if(token == GMLlexer.GMLinteger)
               {
               type_ = GMLinteger;
               value_ = new Integer((int)(lexer.getDoubleval()));
               }
            else if(token == GMLlexer.GMLreal)
               {
               type_ = GMLreal;
               value_ = new Double(lexer.getDoubleval());
               }
            else if(token == GMLlexer.GMLstring)
               {
               type_ = GMLstring;
               value_ = lexer.getStringval();
               }
            else if(token == '[')
               {
               type_ = GMLlist;
               value_ = parseGMLlist_(lexer);
               if(lexer.getTokenType() != ']')
                  throw new ParseError("Expecting GML key or \']\'");
               }
            else
               throw new ParseError(
               "Expecting GML value (number, string, or list)");
            }
         else
            {
            type_ = GMLfile;
            value_ = parseGMLlist_(lexer);
            if(lexer.getTokenType() != GMLlexer.GMLeof)
               throw new ParseError("Expecting GML key or end-of-file");
            }
         }
   
   
   
   
  

      private GMLobject parseGMLlist_(GMLlexer lexer) throws
		java.io.IOException, ParseError
         {
         GMLobject retval = null, prevobj = null;
         int token;
      
         while((token = lexer.nextToken()) == GMLlexer.GMLkey)
            {
            GMLobject newobj = new GMLobject(lexer, lexer.getStringval());
            if(prevobj == null)
               retval = newobj;
            else
               prevobj.next_ = newobj;
            prevobj = newobj;
            }
         return retval;
         }
   
   
   
   
   
   
      /** Print the text representation of the object tree, with "numtabs"
       *  leading tabs.
      **/
      public String toString(int numtabs)
         {
	 if(value_ == null)
	    return "";

         String retval = "";

         int i;
         for(i = 0; i < numtabs; i++)
            retval += "   ";
         if(key_ != null)  // For the top level "GMLfile" object, the key
			   // is null.
            retval += key_;
      
         if(type_ == GMLinteger)
            retval += " " + ((Integer)value_).toString() + "\n";
         else if(type_ == GMLreal)
            {
            // Use GML real format
            double val = ((Double)value_).doubleValue();
         
            if(val == Double.POSITIVE_INFINITY || val == Double.NaN)
               val = Double.MAX_VALUE;
            if(val == Double.NEGATIVE_INFINITY)
               val = Double.MIN_VALUE;
         
            String doublestring = Double.toString(val);
            if(doublestring.indexOf('.') == -1)
            		// No decimal.
               {
               String expstring = "";
               int expstart;
               if((expstart = doublestring.indexOf('e')) != -1)
               			// Exponent is present.
                  {
                  expstring = doublestring.substring(expstart);
                  doublestring = doublestring.substring(0, expstart);
                  }
               doublestring += ".0" + expstring;
               }
            retval += " " + doublestring + "\n";
            }
         else if(type_ == GMLstring) {
	    if(value_ == null)
	       retval += " \"\"\n";
	    else
               retval += " \"" + ((String)value_) + "\"\n";
	    }
         else if(type_ == GMLlist)
         	// List
            {
            retval += " [\n";
         
            GMLobject obj;
            for(obj = (GMLobject)value_; obj != null; obj = obj.next_)
	       if(obj.value_ != null)
                  retval += obj.toString(numtabs + 1);
         
            for(i = 0; i < numtabs; i++)
               retval += "   ";
            retval += "]\n";
            }
         else // File
            {
            GMLobject obj;
            for(obj = (GMLobject)value_; obj != null; obj = obj.next_)
               retval += obj.toString(numtabs);
            }
         return retval;
         }
   
   
   
   
   
   
   
   
      /** Iterator initialized by getGMLSubObject().
       *
       *  Returns the next sub-object matching the path-key and type specified
       *  in a previous call to getGMLSubObject(), or null if no such object
       *  exists.
      **/
      public GMLobject getNextGMLSubObject()
         {
         while(searchobj_ != null && searchobj_.key_ != null &&
	 !(searchobj_.key_.equals(searchkey_) &&
         (searchobj_.type_ == searchtype_ ||
         (searchobj_.type_ == GMLinteger && searchtype_ == GMLreal))))
            searchobj_ = searchobj_.next_;
      
         if(searchobj_ != null && searchobj_.type_ != searchtype_)
            {
         	// Promote the integer to a real.
            searchobj_.type_ = GMLreal;
            searchobj_.value_ = new
		Double((double)((Integer)searchobj_.value_).intValue());
            }
      
         GMLobject retval = searchobj_;
         if(searchobj_ != null)
            searchobj_ = searchobj_.next_;
         return retval;
         }
   


   
      /** Get the first sub-object with path-key "path" and type "type",
       *  or null if no such object exists.
       *
       *  If "create" is true, create the sub-object if it doesn't exist.
       *
       *  If type is GMLreal and a matching GMLinteger is found, the integer
       *  object will be changed to a real.
       *
       *  This function begins an iteration sequence that can continue
       *  with calls to getNextGMLSubObject().
      **/
      public GMLobject getGMLSubObject(String path, int type, boolean create)
         {
         int start, end;
         GMLobject currentobj, obj;
      
         searchobj_ = null;
         currentobj = this;
         start = 0;
      
         String key;
      
         // Should not call this function if object type is not list.
         if(currentobj.type_ != GMLlist && currentobj.type_ != GMLfile)
            return null;
      
         do
            {
            end = path.indexOf('.', start);
            if(end >= 0)
               key = path.substring(start, end);
            else
               key = path.substring(start);
         
            for(obj = (GMLobject)(currentobj.value_); obj != null;
			obj = obj.next_)
               if(obj.key_.equals(key) &&
               ((end >= 0 && (obj.type_ == GMLlist || obj.type_ == GMLfile)) ||
               (end == -1 && (obj.type_ == type ||
               (obj.type_ == GMLinteger && type == GMLreal)))))
                  break;
         
            if(obj == null)
               {
               if(!create)
                  return null;  // Key not found.
               else  // Create key.
                  {
                  obj = new GMLobject(key, GMLlist);
                  if(end == -1)  // Creating end object.
                     obj.type_ = type;
               
               			// Add to front of list;
                  obj.next_ = (GMLobject)currentobj.value_;
                  currentobj.value_ = obj;
                  }
               }
            else if(end == -1 && type != obj.type_)
               {
            	// Promote the integer to a real.
               obj.type_ = GMLreal;
               obj.value_ = new
		 Double((double)((Integer)obj.value_).intValue());
               }
         
            currentobj = obj;
         
            start = end + 1;
            }
         while(start != 0);
      
         searchobj_ = currentobj.next_;
         searchkey_ = key;
         searchtype_ = type;
         return currentobj;
         }
   
   




      /** Insert the keys and values of the first sub-object with path-key
       *  "path" and type "type", into the hash table "hash".
       *
       *  If type is GMLreal and a matching GMLinteger is found, the integer
       *  object will be changed to a real.
      **/
      public void setHashFromGML(String path, int type, Hashtable hash)
      {
         // Should not call this function if object type is not list.
         if(type_ != GMLlist && type_ != GMLfile)
            return;
      
         GMLobject list = getGMLSubObject(path, GMLlist, false);
         if(list == null)
            return;

         GMLobject tmp;
         for(tmp = (GMLobject)list.value_; tmp != null; tmp = tmp.next_) {
            if(type == tmp.type_ ||
		(type == GMLreal && tmp.type_ == GMLinteger)) {
               hash.put(tmp.key_, tmp.value_);
            }
         }
      }





      /** Get the value of the first sub object matching the path-key "path"
       *  and type "type", or null if there is no sub object.
      **/   
      public Object getValue(String path, int type)
         {
         GMLobject obj = getGMLSubObject(path, type, false);
         if(obj == null)
            return null;
      
         return obj.value_;
         }
   
   


   
   // Do not call from a non-list object, or null pointer exception will result.
      public void setValue(String path, int type, Object value)
      {
         GMLobject obj = getGMLSubObject(path, type, true);
         obj.value_ = value;
      }
   
   

   
   // Do not call from a non-list object.
      public void addObject(GMLobject object)
         {
         if(type_ != GMLlist)
            return;
         object.next_ = (GMLobject)value_;
         value_ = object;
         }
   
   
   
   // Do not call from a non-list object.
      public void addObjectToEnd(GMLobject object)
         {
         if(type_ != GMLlist && type_ != GMLfile)
            return;
         GMLobject obj;
         for(obj = (GMLobject)value_; obj != null && obj.next_ != null; obj = obj.next_)
            ;
         if(obj == null)
            value_ = object;
         else
            obj.next_ = object;
         }
   
   
   
   
   // Delete all unsafe sub objects (hierarchical) except those with key "vgj".
      public void deleteUnsafe()
         {
         if(type_ != GMLlist && type_ != GMLfile)
            return;
         GMLobject object = (GMLobject)value_, prevobject = null;
      
         while(object != null)
            {
            int chr;
            if(!object.key_.equals("vgj") && (chr = object.key_.charAt(0)) >= 'A' && chr <= 'Z')
               {
               object = object.next_;
               if(prevobject != null)
                  prevobject.next_ = object;
               else
                  value_ = object;
               }
            else
               {
               object.deleteUnsafe();
               prevobject = object;
               object = object.next_;
               }
            }
         }
   
   
   
   
   
      public void deleteAll(String key, int type)
         {
         GMLobject object = (GMLobject)value_, prevobject = null;
      
         while(object != null)
            {
            if(object.key_.equals(key) && object.type_ == type)
               {
               object = object.next_;
               if(prevobject != null)
                  prevobject.next_ = object;
               else
                  value_ = object;
            
               }
            else
               {
               prevobject = object;
               object = object.next_;
               }
            }
         }
   
     



      /** Remove all null GMLlists from the object tree.
      **/
      public void prune()
      {
         GMLobject obj, prevobj;

	 if(type_ != GMLlist)
	    return;

         for(obj = (GMLobject)(value_); obj != null; obj = obj.next_)
	    obj.prune();

         prevobj = null;
         for(obj = (GMLobject)(value_); obj != null; obj = obj.next_) {
	    if(obj.value_ == null) {
	       if(prevobj != null)
		  prevobj.next_ = obj.next_;
	       else
		  value_ = obj.next_;
	    }
	    else
	       prevobj = obj;
	 }
  }
}