From 1d6957c4d94aebdb08942dd09168a5d8b62a2d79 Mon Sep 17 00:00:00 2001
From: Arthur Drobot <drobotarthur@gmail.com>
Date: Tue, 8 Aug 2017 14:53:34 -0700
Subject: [PATCH] Write a RationalNumber class.

---
 build.gradle                                  |   1 +
 .../nwapw/abacus/number/PreciseNumber.java    |  10 ++
 .../nwapw/abacus/number/RationalNumber.java   | 115 ++++++++++++++++++
 3 files changed, 126 insertions(+)
 mode change 100644 => 100755 build.gradle
 create mode 100755 src/main/java/org/nwapw/abacus/number/RationalNumber.java

diff --git a/build.gradle b/build.gradle
old mode 100644
new mode 100755
index 1a408bc..cd5a65d
--- a/build.gradle
+++ b/build.gradle
@@ -11,6 +11,7 @@ repositories {
 }
 
 dependencies {
+    compile group: 'org.apache.commons', name: 'commons-math3', version: '3.6.1'
     compile 'com.moandjiezana.toml:toml4j:0.7.1'
     compile "org.jetbrains.kotlin:kotlin-stdlib-jre8"
     testCompile 'junit:junit:4.12'
diff --git a/src/main/java/org/nwapw/abacus/number/PreciseNumber.java b/src/main/java/org/nwapw/abacus/number/PreciseNumber.java
index 094e5a9..2d515fc 100755
--- a/src/main/java/org/nwapw/abacus/number/PreciseNumber.java
+++ b/src/main/java/org/nwapw/abacus/number/PreciseNumber.java
@@ -1,6 +1,7 @@
 package org.nwapw.abacus.number;
 
 import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.math.MathContext;
 
 /**
@@ -61,6 +62,15 @@ public class PreciseNumber extends NumberInterface {
         this.value = value;
     }
 
+    /**
+     * Constructs a precise number from the given BigInteger.
+     *
+     * @param value a BigInteger object representing the value of the number.
+     */
+    public PreciseNumber(BigInteger value) {
+        this.value = new BigDecimal(value);
+    }
+
     @Override
     public int getMaxPrecision() {
         return internalContext.getPrecision();
diff --git a/src/main/java/org/nwapw/abacus/number/RationalNumber.java b/src/main/java/org/nwapw/abacus/number/RationalNumber.java
new file mode 100755
index 0000000..62653e6
--- /dev/null
+++ b/src/main/java/org/nwapw/abacus/number/RationalNumber.java
@@ -0,0 +1,115 @@
+package org.nwapw.abacus.number;
+
+import org.apache.commons.math3.fraction.BigFraction;
+import org.apache.commons.math3.fraction.Fraction;
+
+import java.math.BigInteger;
+
+public class RationalNumber extends NumberInterface{
+
+    static final RationalNumber ONE = new RationalNumber(BigFraction.ONE);
+
+    /**
+     * The value of the number.
+     */
+    private BigFraction value;
+
+    /**
+     * Constructs a new instance with the given value.
+     * @param value
+     */
+    public RationalNumber(BigFraction value){
+        this.value = value;
+    }
+
+    @Override
+    public int getMaxPrecision() {
+        return 0;
+    }
+
+    @Override
+    protected NumberInterface multiplyInternal(NumberInterface multiplier) {
+        return new RationalNumber(value.multiply(((RationalNumber)multiplier).value));
+    }
+
+    @Override
+    protected NumberInterface divideInternal(NumberInterface divisor) {
+        return new RationalNumber(value.divide(((RationalNumber)divisor).value));
+    }
+
+    @Override
+    protected NumberInterface addInternal(NumberInterface summand) {
+        return new RationalNumber(value.add(((RationalNumber)summand).value));
+    }
+
+    @Override
+    protected NumberInterface subtractInternal(NumberInterface subtrahend) {
+        return new RationalNumber(value.subtract(((RationalNumber)subtrahend).value));
+    }
+
+    @Override
+    protected NumberInterface negateInternal() {
+        return new RationalNumber(value.negate());
+    }
+
+    @Override
+    protected NumberInterface intPowInternal(int exponent) {
+        return new RationalNumber(value.pow(exponent));
+    }
+
+    @Override
+    public int compareTo(NumberInterface number) {
+        return value.compareTo(((RationalNumber)number).value);
+    }
+
+    @Override
+    public int signum() {
+        return value.getNumerator().signum();
+    }
+
+    @Override
+    protected NumberInterface ceilingInternal() {
+        if(value.getNumeratorAsInt() != 1){
+            return floorInternal().add(ONE);
+        }
+        return this;
+    }
+
+    @Override
+    protected NumberInterface floorInternal() {
+        BigInteger floor = value.bigDecimalValue().toBigInteger();
+        if(value.compareTo(BigFraction.ZERO) < 0 && value.getDenominatorAsInt() != 1){
+            floor = floor.subtract(BigInteger.ONE);
+        }
+        return new RationalNumber(new BigFraction(floor));
+    }
+
+    @Override
+    protected NumberInterface fractionalPartInternal() {
+        return this.subtractInternal(floorInternal());
+    }
+
+    @Override
+    public int intValue() {
+        return 0;
+    }
+
+    @Override
+    protected NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
+        return null;
+    }
+
+    @Override
+    public NumberInterface getMaxError() {
+        return toPreciseNumber().getMaxError();
+    }
+
+    @Override
+    public String toString(){
+        return toPreciseNumber().toString();
+    }
+
+    PreciseNumber toPreciseNumber(){
+        return (PreciseNumber) new PreciseNumber(value.getNumerator()).divideInternal(new PreciseNumber(value.getDenominator()));
+    }
+}