Number Utils

deepak-malik · deepak-malik · commit 17d829e298d9 · 2017-02-13T14:09:28.000-08:00
diff --git a/README.md b/README.md
@@ -151,7 +151,7 @@ Below topics/problems are covered as of now.
 
 **17. Common Utils**
 - [X] [StringUtils](../master/src/com/deepak/data/structures/Utils/StringUtils.java)
-- [ ] NumberUtils
+- [X] [NumberUtils](../master/src/com/deepak/data/structures/Utils/NumberUtils.java)
 - [X] [ArrayUtils](../master/src/com/deepak/data/structures/Utils/ArrayUtils.java)
 - [ ] ListUtils
 - [X] [BooleanUtils](../master/src/com/deepak/data/structures/Utils/BooleanUtils.java)
diff --git a/src/com/deepak/data/structures/Utils/NumberUtils.java b/src/com/deepak/data/structures/Utils/NumberUtils.java
@@ -0,0 +1,100 @@
+/**
+ * Data-Structures-In-Java
+ * NumberUtils.java
+ */
+package com.deepak.data.structures.Utils;
+
+/**
+ * Utilities for Numbers
+ * Note : All of these methods are for integers only,
+ * All others like, Double, float etc will have same implementation
+ * 
+ * @author Deepak
+ */
+public class NumberUtils {
+
+	/**
+	 * Method to convert string to Integer
+	 * 
+	 * @param str
+	 * @return {@link int}
+	 */
+	public static int toInt(final String str) {
+		return toInt(str, 0);
+	}
+
+	/**
+	 * Method to convert string to Integer when a default value is given
+	 * 
+	 * @param str
+	 * @param defaultValue
+	 * @return {@link int}
+	 */
+	public static int toInt(final String str, int defaultValue) {
+		if (str == null) {
+			return defaultValue;
+		}
+		try {
+			return Integer.parseInt(str);
+		} catch (final NumberFormatException exception) {
+			return defaultValue;
+		}
+	}
+
+	/**
+	 * Method to check if string has all zeros
+	 * 
+	 * @param str
+	 * @return {@link boolean}
+	 */
+	public static boolean isAllZeros(final String str) {
+		if (str == null) {
+			return true;
+		}
+		for (int i = 0; i < str.length(); i++) {
+			if (str.charAt(i) != '0') {
+				return false;
+			}
+		}
+		return str.length() > 0;
+	}
+
+	/**
+	 * Find minimum out of Integer array
+	 * 
+	 * @param array
+	 * @return {@link int}
+	 */
+	public static int min(final int... array) {
+		if (array == null) {
+			return 0;
+		}
+		int min = array[0];
+		for (int i = 0; i < array.length; i++) {
+			if (array[i] < min) {
+				min = array[i];
+			}
+		}
+		return min;
+	}
+
+	/**
+	 * Find maximum out of Integer array
+	 * 
+	 * @param array
+	 * @return {@link int}
+	 */
+	public static int max(final int... array) {
+		if (array == null) {
+			return 0;
+		}
+		int max = array[0];
+		for (int i = 0; i < array.length; i++) {
+			if (array[i] > max) {
+				max = array[i];
+			}
+		}
+		return max;
+	}
+
+}
diff --git a/test/com/deepak/data/structures/Utils/NumberUtilsTest.java b/test/com/deepak/data/structures/Utils/NumberUtilsTest.java
@@ -0,0 +1,60 @@
+/**
+ * Data-Structures-In-Java
+ * NumberUtilsTest.java
+ */
+package com.deepak.data.structures.Utils;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test cases for Number Utility Functions
+ * 
+ * @author Deepak
+ */
+public class NumberUtilsTest {
+
+	/**
+	 * Test case to convert string to Integer
+	 */
+	@Test
+	public void testToInt() {
+		Assert.assertEquals(NumberUtils.toInt(null), 0);
+		Assert.assertEquals(NumberUtils.toInt(""), 0);
+		Assert.assertEquals(NumberUtils.toInt("1"), 1);
+		Assert.assertEquals(NumberUtils.toInt(null, 1), 1);
+		Assert.assertEquals(NumberUtils.toInt("", 1), 1);
+		Assert.assertEquals(NumberUtils.toInt("1", 0), 1);
+	}
+
+	/**
+	 * Method to test all zeros
+	 */
+	@Test
+	public void testAllZeros() {
+		Assert.assertEquals(NumberUtils.isAllZeros(null), true);
+		Assert.assertEquals(NumberUtils.isAllZeros("000000"), true);
+		Assert.assertEquals(NumberUtils.isAllZeros("000001"), false);
+	}
+
+	/**
+	 * Method to test find minimum out of a given array
+	 */
+	@Test
+	public void testFindMin() {
+		int[] array = {1, 3, 6, 9, 10, 7};
+		Assert.assertEquals(NumberUtils.min(array), 1);
+		Assert.assertEquals(NumberUtils.min(null), 0);
+	}
+
+	/**
+	 * Method to test find maximum out of a given array
+	 */
+	@Test
+	public void testFindMax() {
+		int[] array = {1, 3, 6, 9, 10, 7};
+		Assert.assertEquals(NumberUtils.max(array), 10);
+		Assert.assertEquals(NumberUtils.max(null), 0);
+	}
+
+}
