1 files changed, 50 insertions, 0 deletions
diff --git a/src/de/fhswf/in/inf/upnfx/util/BinaryOperator.java b/src/de/fhswf/in/inf/upnfx/util/BinaryOperator.java
new file mode 100644
index 0000000..4f704ee
--- /dev/null
+++ b/src/de/fhswf/in/inf/upnfx/util/BinaryOperator.java
@@ -0,0 +1,50 @@
+/**
+ *
+ */
+package de.fhswf.in.inf.upnfx.util;
+
+
+/**
+ * An abstract class for calculations with unary operators.
+ *
+ * @author $Author: $
+ * @version $Revision: $, $Date: $ UTC
+ */
+public abstract class BinaryOperator implements Operator
+{
+   /*
+    * (non-Javadoc)
+    *
+    * @see de.fhswf.in.inf.java1.aufgabe12.Operator#eval(java.util.Stack)
+    */
+   @Override
+   public final void eval(ObservableDoubleStack stack)
+   {
+      if (stack == null)
+      {
+         throw new IllegalArgumentException("Stack must not be null.");
+      }
+
+      if (stack.size() < 2)
+      {
+         throw new IllegalArgumentException(
+               "Binary operation requires two operand.");
+      }
+
+      double d2 = stack.pop();
+      double d1 = stack.pop();
+
+      stack.push(eval(d1, d2));
+   }
+
+   /**
+    * This method implements the calculation.
+    *
+    * @param d1
+    *           The first operator.
+    * @param d2
+    *           The second operator.
+    * @return The result of the calculation.
+    */
+   abstract double eval(double d1, double d2);
+}