Source for org.jfree.formula.function.userdefined.NullFunctionDescription

   1: /**
   2:  * =========================================
   3:  * LibFormula : a free Java formula library
   4:  * =========================================
   5:  *
   6:  * Project Info:  http://reporting.pentaho.org/libformula/
   7:  *
   8:  * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
   9:  *
  10:  * This library is free software; you can redistribute it and/or modify it under the terms
  11:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
  12:  * either version 2.1 of the License, or (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  15:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16:  * See the GNU Lesser General Public License for more details.
  17:  *
  18:  * You should have received a copy of the GNU Lesser General Public License along with this
  19:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20:  * Boston, MA 02111-1307, USA.
  21:  *
  22:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
  23:  * in the United States and other countries.]
  24:  *
  25:  *
  26:  * ------------
  27:  * $Id: NullFunctionDescription.java,v 1.2 2007/04/01 13:51:53 taqua Exp $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: 
  32: package org.jfree.formula.function.userdefined;
  33: 
  34: import org.jfree.formula.function.AbstractFunctionDescription;
  35: import org.jfree.formula.function.FunctionCategory;
  36: import org.jfree.formula.typing.Type;
  37: import org.jfree.formula.typing.coretypes.AnyType;
  38: 
  39: /**
  40:  * Creation-Date: 04.11.2006, 18:28:55
  41:  *
  42:  * @author Thomas Morgner
  43:  */
  44: public class NullFunctionDescription extends AbstractFunctionDescription
  45: {
  46:   public NullFunctionDescription()
  47:   {
  48:     super("org.jfree.formula.function.userdefined.Null-Function");
  49:   }
  50: 
  51:   public int getParameterCount()
  52:   {
  53:     return 0;
  54:   }
  55: 
  56:   public boolean isInfiniteParameterCount()
  57:   {
  58:     return false;
  59:   }
  60: 
  61:   public Type getParameterType(int position)
  62:   {
  63:     return AnyType.TYPE;
  64:   }
  65: 
  66:   public Type getValueType()
  67:   {
  68:     return AnyType.TYPE;
  69:   }
  70: 
  71:   /**
  72:    * Defines, whether the parameter at the given position is mandatory. A
  73:    * mandatory parameter must be filled in, while optional parameters need not
  74:    * to be filled in.
  75:    *
  76:    * @return
  77:    */
  78:   public boolean isParameterMandatory(int position)
  79:   {
  80:     return false;
  81:   }
  82: 
  83:   /**
  84:    * Returns the default value for an optional parameter. If the value returned
  85:    * here is null, then this either means, that the parameter is mandatory or
  86:    * that the default value is computed by the expression itself.
  87:    *
  88:    * @param position
  89:    * @return
  90:    */
  91:   public Object getDefaultValue(int position)
  92:   {
  93:     return null;
  94:   }
  95: 
  96:   public FunctionCategory getCategory()
  97:   {
  98:     return UserDefinedFunctionCategory.CATEGORY;
  99:   }
 100: 
 101: }