Source for java.math.MathContext

   1: /* MathContext.java -- 
   2:    Copyright (C) 1999, 2000, 2002, 2004, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.math;
  40: 
  41: import java.io.Serializable;
  42: 
  43: /**
  44:  * Immutable objects describing settings such as rounding mode and digit
  45:  * precision for numerical operations such as those in the BigDecimal class.
  46:  * @author Anthony Balkissoon abalkiss at redhat dot com
  47:  *
  48:  */
  49: public final class MathContext implements Serializable
  50: {
  51:   
  52:   /**
  53:    * This is the serialVersionUID reported here:
  54:    * java.sun.com/j2se/1.5.0/docs/api/serialized-form.html#java.math.MathContext
  55:    */
  56:   private static final long serialVersionUID = 5579720004786848255L;
  57:   
  58:   private int precision;
  59:     
  60:   /**
  61:    * Constructs a new MathContext with the specified precision and with HALF_UP
  62:    * rounding.
  63:    * @param setPrecision the precision for the new MathContext
  64:    * 
  65:    * @throws IllegalArgumentException if precision is < 0.
  66:    */
  67:   public MathContext(int setPrecision)
  68:   {
  69:     if (setPrecision < 0)
  70:       throw new IllegalArgumentException("Precision cannot be less than zero.");
  71:     precision = setPrecision;
  72:   }
  73:     
  74:   /**
  75:    * Constructs a MathContext from a String that has the same form as one
  76:    * produced by the toString() method.
  77:    * @param val
  78:    * 
  79:    * @throws IllegalArgumentException if the String is not in the correct
  80:    * format or if the precision specified is < 0.
  81:    */
  82:   public MathContext(String val)
  83:   {
  84:     try
  85:     {
  86:       int roundingModeIndex = val.indexOf("roundingMode", 10);
  87:       precision = Integer.parseInt(val.substring(10, roundingModeIndex - 1));
  88:     }
  89:     catch (NumberFormatException nfe)
  90:     {
  91:       throw new IllegalArgumentException("String not in correct format");
  92:     }
  93:     catch (IllegalArgumentException iae)
  94:     {
  95:       throw new IllegalArgumentException("String not in correct format");
  96:     }
  97:     if (precision < 0)
  98:       throw new IllegalArgumentException("Precision cannot be less than 0.");
  99:   }
 100:   
 101:   /**
 102:    * Returns true if x is a MathContext and has the same precision setting
 103:    * and rounding mode as this MathContext.
 104:    * 
 105:    * @return true if the above conditions hold
 106:    */
 107:   public boolean equals(Object x)
 108:   {
 109:     if (!(x instanceof MathContext))
 110:       return false;
 111:     MathContext mc = (MathContext)x;
 112:     return mc.precision == this.precision;
 113:   }
 114:   
 115:   /**
 116:    * Returns the precision setting.
 117:    * @return the precision setting.
 118:    */
 119:   public int getPrecision()
 120:   {
 121:     return precision;
 122:   }
 123:   
 124:   /**
 125:    * Returns "precision=p roundingMode=MODE" where p is an int giving the 
 126:    * precision and MODE is UP, DOWN, HALF_UP, HALF_DOWN, HALF_EVEN, CEILING,
 127:    * FLOOR, or UNNECESSARY corresponding to rounding modes.
 128:    * 
 129:    * @return a String describing this MathContext
 130:    */
 131:   public String toString()
 132:   {
 133:     return "precision="+precision;
 134:   }
 135:   
 136:   /**
 137:    * Returns the hashcode for this MathContext.
 138:    * @return the hashcode for this MathContext.
 139:    */
 140:   public int hashCode()
 141:   {
 142:     return precision;
 143:   }
 144: }