vnull.java

一个简单的visio程序。

package HECore.stddata; 
import HPCore.Exception.*;

public class VNull extends Variant {
  
  public VNull( )
    {
      
    }
   
   /**
     * Returns Null type.
     */  
   
  public short getType()
   {

     return V_NULL;
   }

  /**
    * Convert Current VNull Object to String and return String.
    */

  public String toString() 
    {
     return  "Null";
    }
  
  
  /**
    *  Returns Null.
    */

  public String strValue() 
    {
     return  "Null";
    }

  public  Variant Add(Variant b) 
    {
      return new VNull();
    }

  public Variant Sub(Variant b) 
		{
     return new VNull();
		}

		public Variant Mult(Variant b)
		{
		   return new VNull();
		}

		public Variant Div(Variant b) 
		{
		   return new VNull();
		}

		public Variant DDiv(Variant b)
		{
		   return new VNull();
		}

		public Variant And(Variant b) throws HpException
		{
	   if(b.getType() ==V_BOL)
				  {
						 if(b.dblValue() !=0)
							   return new VNull();
				   else
							   return new VBoolean(false);
       }
				else
				 if(b.getType() ==V_EMPTY)
					    return new VLong(0);
				else
				    return new VNull();
   }

			public Variant Xor(Variant b) 
			{
		    	return new VNull();  
			}

			public Variant Or(Variant b) throws HpException
			{
			  short btype =b.getType();
					switch(btype)
					{
					case V_BOL:
					    if(b.dblValue() !=0)
									   return new VBoolean(true);
								 else
									   return new VNull();
     case V_BYTE:
					       return new VByte((double)b.lngValue());
					case V_INT:
					       return new VInt((double)b.lngValue());
				 case V_VAR:
					case V_EMPTY:
					       return new VNull();
										default: return new VLong((double)b.lngValue());
					}
			}

			public Variant Eqv(Variant b)
			{
			  return new VNull();
			}

			public Variant Imp(Variant b) throws HpException
			{
			   short btype=b.getType();
						switch(btype)
						{
						 case V_BOL:
							     if(b.dblValue() !=0)
												  return new VBoolean(true);
												else
												   return new VNull();
				   case V_BYTE:
							      return new VByte((double)b.lngValue());
				   case V_INT:
							      return new VInt((double)b.lngValue());
				   case V_VAR:
							case V_EMPTY:
							      return new VNull();
				   default: return new VLong((double)b.lngValue());
						}
			}

			public Variant Like(Variant b)
			{
			  return new VNull();
			}

	  public Variant Great(Variant b,boolean flag)
			{
			   return new VNull();
			}

			public Variant Less(Variant b,boolean flag)
			  {
					  return new VNull();
					}

				public Variant Equal(Variant b,boolean flag)
				{
				  return new VNull();
				}

				public Variant GreatEqual(Variant b,boolean flag)
				{
				   return new VNull();
				}
    
				public Variant LessEqual(Variant b,boolean flag)
				{
				   return new VNull();
				}

				public Variant NotEqual(Variant b,boolean flag)
				{
				   return new VNull();
				}

				public VString Link(Variant b)
				{
				  return new VString(b.toString());
				}

				public Variant Mod(Variant b)
				{
				   return new VNull();
				}

				public Variant Pow(Variant b)
				{
				   return new VNull();
				}

}