1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/task2/solution10/src/org/apidesign/apifest08/currency/ConstantRateConverter.java	Wed Oct 01 10:43:05 2008 +0200
     1.3 @@ -0,0 +1,44 @@
     1.4 +package org.apidesign.apifest08.currency;
     1.5 +
     1.6 +import java.util.*;
     1.7 +
     1.8 +final class ConstantRateConverter implements CurrencyConverter {
     1.9 +
    1.10 +	private final Currency from;
    1.11 +	private final Currency to;
    1.12 +
    1.13 +	private final double rate;
    1.14 +
    1.15 +	public ConstantRateConverter(Currency from, Currency to, double rate) throws IllegalArgumentException {
    1.16 +		if (from == null || to == null)
    1.17 +			throw new NullPointerException("None of the currencies can be null");
    1.18 +		if (from.equals(to))
    1.19 +			throw new IllegalArgumentException("Cannot create converter with two equal currencies");
    1.20 +		this.from = from;
    1.21 +		this.to = to;
    1.22 +		this.rate = rate;
    1.23 +	}
    1.24 +
    1.25 +	@Override
    1.26 +	public double convert(double value, String from, String to)
    1.27 +			throws CurrencyConversionException, NullPointerException {
    1.28 +		return convert(value, Currency.getInstance(from), Currency.getInstance(to));
    1.29 +	}
    1.30 +
    1.31 +	@Override
    1.32 +	public double convert(double value, Currency from, Currency to)
    1.33 +			throws NullPointerException, CurrencyConversionException {
    1.34 +
    1.35 +		if (this.from.equals(from)) {
    1.36 +			if (!this.to.equals(to))
    1.37 +				throw new CurrencyConversionException(from, to, "Unsupported currency");
    1.38 +			return value * rate;
    1.39 +		}
    1.40 +		if (this.from.equals(to)) {
    1.41 +			if (!this.to.equals(from))
    1.42 +				throw new CurrencyConversionException(from, to, "Unsupported currency");
    1.43 +			return value / rate;
    1.44 +		}
    1.45 +		throw new CurrencyConversionException(from, to, "Unsupported currency"); 
    1.46 +	}
    1.47 +}