Assignment No.12 first complete implementation.

1 files changed, 86 insertions, 0 deletions

diff --git a/src/de/fhswf/in/inf/java1/aufgabe12/UnaryTemplate.java b/src/de/fhswf/in/inf/java1/aufgabe12/UnaryTemplate.java
new file mode 100644
index 0000000..d345af1
--- /dev/null
+++ b/src/de/fhswf/in/inf/java1/aufgabe12/UnaryTemplate.java
@@ -0,0 +1,86 @@
+/**
+ * 
+ */
+package de.fhswf.in.inf.java1.aufgabe12;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Uses Reflection API to get the method for calculation.
+ *
+ * @author $Author: $
+ * @version $Revision: $, $Date: $ UTC
+ */
+public class UnaryTemplate extends UnaryOperator
+{
+
+   private Method operator;
+
+   /**
+    * Gets the operator function from the Math class.
+    *
+    * @param mathFunction
+    *           The name of the operation.
+    */
+   public UnaryTemplate(String mathFunction)
+   {
+      if (mathFunction == null)
+      {
+         throw new IllegalArgumentException("Operation can't be null.");
+      }
+
+      if (mathFunction.isEmpty())
+      {
+         throw new IllegalArgumentException("Operations can't be empty.");
+      }
+
+      try
+      {
+         operator = Math.class.getMethod(mathFunction, Double.TYPE);
+      }
+      catch (NoSuchMethodException e)
+      {
+         throw new IllegalArgumentException("Not a valid Operator.", e);
+      }
+      catch (SecurityException e)
+      {
+         throw new IllegalArgumentException("Security violation.", e);
+      }
+
+   }
+
+   /*
+    * (non-Javadoc)
+    * 
+    * @see de.fhswf.in.inf.java1.aufgabe12.UnaryOperator#eval(double)
+    */
+   @Override
+   final double eval(double d)
+   {
+      Object tmp = null;
+      try
+      {
+         tmp = operator.invoke(null, d);
+      }
+      catch (IllegalAccessException e)
+      {
+         throw new IllegalStateException("Can't access method.", e);
+      }
+      catch (IllegalArgumentException e)
+      {
+         throw new IllegalStateException(
+               "Argument for Math function is not double.", e);
+      }
+      catch (InvocationTargetException e)
+      {
+         if (e.getCause() instanceof IllegalArgumentException)
+         {
+            throw new IllegalArgumentException("Illegal Argument.", e);
+         }
+         throw new IllegalStateException("Unexpected exception.", e);
+      }
+      return (double) tmp;
+   }
+
+}