diff -r 251d0ed461fb -r 58ec6da75f6f task4/solution02/src/org/apidesign/apifest08/currency/CompositeConvertor.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/task4/solution02/src/org/apidesign/apifest08/currency/CompositeConvertor.java	Sat Oct 11 23:38:46 2008 +0200
@@ -0,0 +1,75 @@
+package org.apidesign.apifest08.currency;
+
+import java.io.Serializable;
+import java.util.Arrays;
+import java.util.Currency;
+
+/**
+ * Convertor that is composed from other convertors. 
+ * @author lukas
+ *
+ */
+class CompositeConvertor implements ExtendedConvertor, Serializable {
+
+	private static final long serialVersionUID = -2702026568249130055L;
+	
+	private final ExtendedConvertor[] convertors;
+
+
+	public CompositeConvertor(ExtendedConvertor... convertors) {
+		this.convertors = convertors.clone();
+		for (ExtendedConvertor convertor: this.convertors)
+		{
+			if (convertor==null)
+			{
+				throw new NullPointerException("One of the convertors to be merged is null");
+			}
+		}
+	}
+
+	/**
+	 * Returns true if the composite contains convertor that supports given conversion.
+	 */
+	public boolean isConversionSupported(Currency from, Currency to) {
+		return findConvertorFor(from, to)!=null;
+	}
+
+
+	/**
+	 * If the composite contains convertor that supports given conversion, delegates to its convert method.
+	 * Throws {@link IllegalArgumentException} convertor supporting given conversion is not found. 
+	 */
+	public Money convert(Money amount, Currency destinationCurrency) throws IllegalArgumentException {
+		ExtendedConvertor convertor = findConvertorFor(amount.getCurrency(), destinationCurrency);
+		if (convertor!=null)
+		{
+			return convertor.convert(amount, destinationCurrency);
+		}
+		throw new IllegalArgumentException("Conversion not supported. Can not convert to "+destinationCurrency+".");
+	}
+	
+	/**
+	 * Finds convertor for given currencies. If not found, returns null. 
+	 * @param from
+	 * @param to
+	 * @return
+	 */
+	ExtendedConvertor findConvertorFor(Currency from, Currency to) {
+		//does linear search, in the future can cache the results.
+		for (ExtendedConvertor convertor:convertors)
+		{
+			if (convertor.isConversionSupported(from, to))
+			{
+				return convertor;
+			}
+		}
+		return null;
+	}
+	
+
+	@Override
+	public String toString() {
+		return getClass().getName()+" converts "+Arrays.toString(convertors);
+	}
+
+}