Added CacheAwareFactorialDecorator

Author: jharting

lesson02-cdi/src/main/java/cz/muni/fi/pv243/lesson02/factorial/CacheAwareFactorialDecorator.java

@@ -0,0 +1,36 @@
+package cz.muni.fi.pv243.lesson02.factorial;
+
+import java.math.BigInteger;
+
+import javax.decorator.Decorator;
+import javax.decorator.Delegate;
+import javax.enterprise.inject.Any;
+import javax.inject.Inject;
+
+/**
+ * Decorator that checks the {@link FactorialCache} before initiating computation. If the result is found in cache, it is
+ * returned.
+ *
+ * @author Jozef Hartinger
+ *
+ */
+@Decorator
+public class CacheAwareFactorialDecorator implements Factorial {
+
+    @Inject
+    @Delegate
+    @Any
+    private Factorial delegate;
+
+    @Inject
+    private FactorialCache cache;
+
+    @Override
+    public BigInteger compute(long number) {
+        BigInteger result = cache.get(number);
+        if (result == null) {
+            result = delegate.compute(number);
+        }
+        return result;
+    }
+}

lesson02-cdi/src/main/java/cz/muni/fi/pv243/lesson02/factorial/FactorialCache.java

@@ -8,6 +8,7 @@
 import javax.ejb.LockType;
 import javax.ejb.Singleton;
 import javax.enterprise.event.Observes;
+import javax.inject.Named;
 
 import cz.muni.fi.pv243.lesson02.factorial.util.FactorialComputationFinished;
 
@@ -19,6 +20,7 @@
  *
  */
 @Singleton
+@Named
 public class FactorialCache {
     private final Map<Long, BigInteger> cachedResults = new HashMap<Long, BigInteger>();
 

lesson02-cdi/src/main/webapp/WEB-INF/beans.xml

@@ -6,4 +6,7 @@
 	xsi:schemaLocation="
         http://java.sun.com/xml/ns/javaee 
         http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
+	<decorators>
+		<class>cz.muni.fi.pv243.lesson02.factorial.CacheAwareFactorialDecorator</class>
+	</decorators>
 </beans>

lesson02-cdi/src/main/webapp/factorial.xhtml

@@ -12,6 +12,7 @@
 			</h:inputText>
 			<h:commandButton value="Compute" />
 			<h:commandButton immediate="true" value="Reset" />
+			<h:commandButton immediate="true" value="Clear cache" action="#{factorialCache.clear}" />
 			<br />
 			<br />
 			<h:messages />