/**
* Constructs a new {@code MathContext} from a string.
*
* <p>The string must be in the same format as that produced by the {@link #toString} method.
*
* <p>An {@code IllegalArgumentException} is thrown if the precision section of the string is out
* of range ({@code < 0}) or the string is not in the format created by the {@link #toString}
* method.
*
* @param val The string to be parsed
* @throws IllegalArgumentException if the precision section is out of range or of incorrect
* format
* @throws NullPointerException if the argument is {@code null}
*/
public MathContext(String val) {
boolean bad = false;
int setPrecision;
if (val == null) throw new NullPointerException("null String");
try { // any error here is a string format problem
if (!val.startsWith("precision=")) throw new RuntimeException();
int fence = val.indexOf(' '); // could be -1
int off = 10; // where value starts
setPrecision = Integer.parseInt(val.substring(10, fence));
if (!val.startsWith("roundingMode=", fence + 1)) throw new RuntimeException();
off = fence + 1 + 13;
String str = val.substring(off, val.length());
roundingMode = RoundingMode.valueOf(str);
} catch (RuntimeException re) {
throw new IllegalArgumentException("bad string format");
}
if (setPrecision < MIN_DIGITS) throw new IllegalArgumentException("Digits < 0");
// the other parameters cannot be invalid if we got here
precision = setPrecision;
}
