Rename Number to NumberInterface. Fix factorial function. Add toString override to NaiveNumber.

src/org/nwapw/abacus/number/Function.java

@@ -4,15 +4,15 @@ import java.util.HashMap;
 
 public abstract class Function {
 
-    private static final HashMap<Class<? extends Number>, Integer> priorityMap =
-            new HashMap<Class<? extends Number>, Integer>() {{
+    private static final HashMap<Class<? extends NumberInterface>, Integer> priorityMap =
+            new HashMap<Class<? extends NumberInterface>, Integer>() {{
                 put(NaiveNumber.class, 0);
             }};
 
-    protected abstract boolean matchesParams(Number[] params);
-    protected abstract Number applyInternal(Number[] params);
+    protected abstract boolean matchesParams(NumberInterface[] params);
+    protected abstract NumberInterface applyInternal(NumberInterface[] params);
 
-    public Number apply(Number...params) {
+    public NumberInterface apply(NumberInterface...params) {
         if(!matchesParams(params)) return null;
         return applyInternal(params);
     }

src/org/nwapw/abacus/number/FunctionDatabase.java

@@ -9,13 +9,13 @@ public class FunctionDatabase {
     private void registerDefault(){
         functions.put("+", new Function() {
             @Override
-            protected boolean matchesParams(Number[] params) {
+            protected boolean matchesParams(NumberInterface[] params) {
                 return params.length >= 1;
             }
 
             @Override
-            protected Number applyInternal(Number[] params) {
-                Number sum = params[0];
+            protected NumberInterface applyInternal(NumberInterface[] params) {
+                NumberInterface sum = params[0];
                 for(int i = 1; i < params.length; i++){
                     sum = sum.add(params[i]);
                 }
@@ -25,25 +25,25 @@ public class FunctionDatabase {
 
         functions.put("-", new Function() {
             @Override
-            protected boolean matchesParams(Number[] params) {
+            protected boolean matchesParams(NumberInterface[] params) {
                 return params.length == 2;
             }
 
             @Override
-            protected Number applyInternal(Number[] params) {
+            protected NumberInterface applyInternal(NumberInterface[] params) {
                 return params[0].subtract(params[1]);
             }
         });
 
         functions.put("*", new Function() {
             @Override
-            protected boolean matchesParams(Number[] params) {
+            protected boolean matchesParams(NumberInterface[] params) {
                 return params.length >= 1;
             }
 
             @Override
-            protected Number applyInternal(Number[] params) {
-                Number product = params[1];
+            protected NumberInterface applyInternal(NumberInterface[] params) {
+                NumberInterface product = params[1];
                 for(int i = 1; i < params.length; i++){
                     product = product.multiply(params[i]);
                 }
@@ -53,29 +53,28 @@ public class FunctionDatabase {
 
         functions.put("/", new Function() {
             @Override
-            protected boolean matchesParams(Number[] params) {
+            protected boolean matchesParams(NumberInterface[] params) {
                 return params.length == 2;
             }
 
             @Override
-            protected Number applyInternal(Number[] params) {
+            protected NumberInterface applyInternal(NumberInterface[] params) {
                 return params[0].divide(params[1]);
             }
         });
 
         functions.put("!", new Function() {
             @Override
-            protected boolean matchesParams(Number[] params) {
+            protected boolean matchesParams(NumberInterface[] params) {
                 return params.length == 1;
             }
 
             @Override
-            protected Number applyInternal(Number[] params) {
-                Number factorial = params[0];
-                Number multiplier = params[0];
+            protected NumberInterface applyInternal(NumberInterface[] params) {
+                NumberInterface factorial = params[0];
+                NumberInterface multiplier = params[0];
                 //It is necessary to later prevent calls of factorial on anything but non-negative integers.
-                while(multiplier.signum() == 1){
-                    multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()));
+                while((multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()))).signum() == 1){
                     factorial = factorial.multiply(multiplier);
                 }
                 return factorial;

src/org/nwapw/abacus/number/NaiveNumber.java

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.number;
 
-public class NaiveNumber implements Number {
+public class NaiveNumber implements NumberInterface {
 
     private double value;
 
@@ -8,8 +8,8 @@ public class NaiveNumber implements Number {
         this.value = value;
     }
 
-    static final NaiveNumber ZERO = new NaiveNumber(0);
-    static final NaiveNumber ONE = new NaiveNumber(1);
+    public static final NaiveNumber ZERO = new NaiveNumber(0);
+    public static final NaiveNumber ONE = new NaiveNumber(1);
 
     @Override
     public int precision() {
@@ -17,33 +17,33 @@ public class NaiveNumber implements Number {
     }
 
     @Override
-    public Number multiply(Number multiplier) {
+    public NumberInterface multiply(NumberInterface multiplier) {
         return new NaiveNumber(value * ((NaiveNumber)multiplier).value);
     }
 
     @Override
-    public Number divide(Number divisor) {
+    public NumberInterface divide(NumberInterface divisor) {
         return new NaiveNumber(value / ((NaiveNumber)divisor).value);
     }
 
     @Override
-    public Number add(Number summand) {
+    public NumberInterface add(NumberInterface summand) {
         return new NaiveNumber(value + ((NaiveNumber)summand).value);
     }
 
     @Override
-    public Number subtract(Number subtrahend) {
+    public NumberInterface subtract(NumberInterface subtrahend) {
         return new NaiveNumber(value - ((NaiveNumber)subtrahend).value);
     }
 
     @Override
-    public Number negate() {
+    public NumberInterface negate() {
         return new NaiveNumber(-value);
     }
 
     @Override
-    public Number intPow(int exponent) {
-        Number power = this;
+    public NumberInterface intPow(int exponent) {
+        NumberInterface power = this;
         for(int currentExponent = 1; currentExponent <= exponent; currentExponent++){
             power = power.multiply(this);
         }
@@ -51,7 +51,7 @@ public class NaiveNumber implements Number {
     }
 
     @Override
-    public int compareTo(Number number) {
+    public int compareTo(NumberInterface number) {
         NaiveNumber num = (NaiveNumber) number;
         return Double.compare(value, num.value);
     }
@@ -62,10 +62,14 @@ public class NaiveNumber implements Number {
     }
 
     @Override
-    public Number promoteTo(Class<? extends Number> toClass) {
+    public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
         if(toClass == this.getClass()) return this;
         return null;
     }
 
+    public String toString(){
+        return Double.toString(value);
+    }
+
 }
 

src/org/nwapw/abacus/number/Number.java

@@ -1,17 +0,0 @@
-package org.nwapw.abacus.number;
-
-public interface Number {
-
-    int precision();
-    Number multiply(Number multiplier);
-    Number divide(Number divisor);
-    Number add(Number summand);
-    Number subtract(Number subtrahend);
-    Number negate();
-    Number intPow(int exponent);
-    int compareTo(Number number);
-    int signum();
-
-    Number promoteTo(Class<? extends Number> toClass);
-
-}

src/org/nwapw/abacus/number/NumberInterface.java

@@ -0,0 +1,17 @@
+package org.nwapw.abacus.number;
+
+public interface NumberInterface {
+
+    int precision();
+    NumberInterface multiply(NumberInterface multiplier);
+    NumberInterface divide(NumberInterface divisor);
+    NumberInterface add(NumberInterface summand);
+    NumberInterface subtract(NumberInterface subtrahend);
+    NumberInterface negate();
+    NumberInterface intPow(int exponent);
+    int compareTo(NumberInterface number);
+    int signum();
+
+    NumberInterface promoteTo(Class<? extends NumberInterface> toClass);
+
+}