/* MathContext.java -- 
   Copyright (C) 1999, 2000, 2002, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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any later version.

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General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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package java.math;

import java.io.Serializable;

/**
 * Immutable objects describing settings such as rounding mode and digit
 * precision for numerical operations such as those in the BigDecimal class.
 * @author Anthony Balkissoon abalkiss at redhat dot com
 *
 */
public final class MathContext implements Serializable
{
  
  /**
   * This is the serialVersionUID reported here:
   * java.sun.com/j2se/1.5.0/docs/api/serialized-form.html#java.math.MathContext
   */
  private static final long serialVersionUID = 5579720004786848255L;
  
  private int precision;
    
  /**
   * Constructs a new MathContext with the specified precision and with HALF_UP
   * rounding.
   * @param setPrecision the precision for the new MathContext
   * 
   * @throws IllegalArgumentException if precision is < 0.
   */
  public MathContext(int setPrecision)
  {
    if (setPrecision < 0)
      throw new IllegalArgumentException("Precision cannot be less than zero.");
    precision = setPrecision;
  }
    
  /**
   * Constructs a MathContext from a String that has the same form as one
   * produced by the toString() method.
   * @param val
   * 
   * @throws IllegalArgumentException if the String is not in the correct
   * format or if the precision specified is < 0.
   */
  public MathContext(String val)
  {
    try
    {
      int roundingModeIndex = val.indexOf("roundingMode", 10);
      precision = Integer.parseInt(val.substring(10, roundingModeIndex - 1));
    }
    catch (NumberFormatException nfe)
    {
      throw new IllegalArgumentException("String not in correct format");
    }
    catch (IllegalArgumentException iae)
    {
      throw new IllegalArgumentException("String not in correct format");
    }
    if (precision < 0)
      throw new IllegalArgumentException("Precision cannot be less than 0.");
  }
  
  /**
   * Returns true if x is a MathContext and has the same precision setting
   * and rounding mode as this MathContext.
   * 
   * @return true if the above conditions hold
   */
  public boolean equals(Object x)
  {
    if (!(x instanceof MathContext))
      return false;
    MathContext mc = (MathContext)x;
    return mc.precision == this.precision;
  }
  
  /**
   * Returns the precision setting.
   * @return the precision setting.
   */
  public int getPrecision()
  {
    return precision;
  }
  
  /**
   * Returns "precision=p roundingMode=MODE" where p is an int giving the 
   * precision and MODE is UP, DOWN, HALF_UP, HALF_DOWN, HALF_EVEN, CEILING,
   * FLOOR, or UNNECESSARY corresponding to rounding modes.
   * 
   * @return a String describing this MathContext
   */
  public String toString()
  {
    return "precision="+precision;
  }
  
  /**
   * Returns the hashcode for this MathContext.
   * @return the hashcode for this MathContext.
   */
  public int hashCode()
  {
    return precision;
  }
}