From e3f7cf6b2c2f17ca70dd612a2c3993210a4ea6e3 Mon Sep 17 00:00:00 2001
From: Marcin Krykowski <Marcin.Krykowski@gmail.com>
Date: Sat, 13 Jun 2020 23:40:19 +0100
Subject: [PATCH] Add formating methods for percentages, currencies and big
 numbers

---
 .../baeldung/formatNumber/FormatNumber.java   | 29 +++++++++++++
 .../formatNumber/FormatNumberUnitTest.java    | 42 +++++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/java-numbers-3/src/main/java/com/baeldung/formatNumber/FormatNumber.java b/java-numbers-3/src/main/java/com/baeldung/formatNumber/FormatNumber.java
index 6a16fffa7e..b7c54eb6be 100644
--- a/java-numbers-3/src/main/java/com/baeldung/formatNumber/FormatNumber.java
+++ b/java-numbers-3/src/main/java/com/baeldung/formatNumber/FormatNumber.java
@@ -40,5 +40,34 @@ public class FormatNumber {
     public static String withStringFormat(double value, int places) {
         return String.format("%." + places + "f", value);
     }
+
+    public static String byPaddingOutZeros(int value, int paddingLength) {
+        return String.format("%0" + paddingLength + "d", value);
+    }
+
+    public static double withTwoDecimalPlaces(double value) {
+        DecimalFormat df = new DecimalFormat("#.00");
+        return new Double(df.format(value));
+    }
+
+    public static String withLongNumbers(double value) {
+        DecimalFormat df = new DecimalFormat("###,###,###");
+        return df.format(value);
+    }
+
+    public static String forPercentages(double value, Locale localisation) {
+        NumberFormat nf = NumberFormat.getPercentInstance(localisation);
+        return nf.format(value);
+    }
+
+    public static String currencyWithChosenLocalisation(double value, Locale localisation) {
+        NumberFormat nf = NumberFormat.getCurrencyInstance(localisation);
+        return nf.format(value);
+    }
+
+    public static String currencyWithDefaultLocalisation(double value) {
+        NumberFormat nf = NumberFormat.getCurrencyInstance();
+        return nf.format(value);
+    }
 }
 
diff --git a/java-numbers-3/src/test/java/com/baeldung/formatNumber/FormatNumberUnitTest.java b/java-numbers-3/src/test/java/com/baeldung/formatNumber/FormatNumberUnitTest.java
index ef3700e27a..514ca45cdb 100644
--- a/java-numbers-3/src/test/java/com/baeldung/formatNumber/FormatNumberUnitTest.java
+++ b/java-numbers-3/src/test/java/com/baeldung/formatNumber/FormatNumberUnitTest.java
@@ -2,6 +2,8 @@ package com.baeldung.formatNumber;
 
 import org.junit.Test;
 
+import java.util.Locale;
+
 import static com.baeldung.formatNumber.FormatNumber.*;
 import static org.assertj.core.api.Assertions.*;
 
@@ -43,4 +45,44 @@ public class FormatNumberUnitTest {
         assertThat(withMathRound(F, 2)).isEqualTo(8.7);
         assertThat(withMathRound(F, 3)).isEqualTo(8.699);
     }
+
+    @Test
+    public void givenIntegerNumber_whenFormatNumber_byPaddingOutZeros_thenGetExpectedResult() {
+        int value = 1;
+        assertThat(byPaddingOutZeros(value, 3)).isEqualTo("001");
+    }
+
+    @Test
+    public void givenIntegerNumber_whenFormatNumber_withTwoDecimalPlaces_thenGetExpectedResult() {
+        int value = 12;
+        assertThat(withTwoDecimalPlaces(value)).isEqualTo(12.00);
+    }
+
+    @Test
+    public void givenIntegerNumber_whenFormatNumber_withLongNumbers_thenGetExpectedResult() {
+        int value = 123456789;
+        assertThat(withLongNumbers(value)).isEqualTo("123,456,789");
+    }
+
+    @Test
+    public void givenDecimalNumber_whenFormatNumber_forPercentages_thenGetExpectedResult() {
+        double value = 25f / 100f;
+        assertThat(forPercentages(value, new Locale("en", "US"))).isEqualTo("25%");
+        assertThat(forPercentages(value, new Locale("pl", "PL"))).isEqualTo("25%");
+    }
+
+    @Test
+    public void givenCurrency_whenFormatNumber_currencyWithChosenLocalisation_thenGetExpectedResult() {
+        double value = 23_500;
+        assertThat(currencyWithChosenLocalisation(value, new Locale("en", "US"))).isEqualTo("$23,500.00");
+        assertThat(currencyWithChosenLocalisation(value, new Locale("zh", "CN"))).isEqualTo("￥23,500.00");
+        assertThat(currencyWithChosenLocalisation(value, new Locale("pl", "PL"))).isEqualTo("23 500 zł");
+    }
+
+    @Test
+    public void givenCurrency_whenFormatNumber_currencyWithDefaultLocalisation_thenGetExpectedResult() {
+        double value = 23_500;
+        assertThat(currencyWithDefaultLocalisation(value)).isEqualTo("£23,500.00");
+    }
+
 }