first commit

java/expression/Add.java

@@ -0,0 +1,44 @@
+package expression;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * @author Doschennikov Nikita (me@fymio.us)
+ */
+public class Add extends AbstractBinaryOperation {
+
+    public Add(AbstractExpression l, AbstractExpression r) {
+        super(l, r);
+    }
+
+    @Override
+    protected String getOperator() {
+        return "+";
+    }
+
+    @Override
+    protected int getPriority() {
+        return 1;
+    }
+
+    @Override
+    protected boolean isRightAssoc() {
+        return false;
+    }
+
+    @Override
+    protected int applyInt(int a, int b) {
+        return a + b;
+    }
+
+    @Override
+    protected BigInteger applyBi(BigInteger a, BigInteger b) {
+        return a.add(b);
+    }
+
+    @Override
+    protected BigDecimal applyBd(BigDecimal a, BigDecimal b) {
+        return a.add(b);
+    }
+}