Some more string utils methods

Author: Deepak Malik

src/com/deepak/data/structures/Utils/StringUtils.java

@@ -18,6 +18,7 @@ public class StringUtils {
 	 * @return {@link boolean}
 	 */
 	public static boolean isEmpty(final CharSequence cs) {
+		/* String is empty is it is null or length is 0 */
 		return cs == null || cs.length() == 0;
 	}
 
@@ -28,9 +29,11 @@ public static boolean isEmpty(final CharSequence cs) {
 	 * @return {@link boolean}
 	 */
 	public static boolean isAnyEmpty(final CharSequence... css) {
+		/* Input has to be array */
 		if (ArrayUtils.isEmpty(css)) {
 			return false;
 		}
+		/* Check for each character */
 		for (CharSequence cs : css) {
 			if (isEmpty(cs)) {
 				return true;
@@ -48,9 +51,11 @@ public static boolean isAnyEmpty(final CharSequence... css) {
 	 */
 	public static boolean isBlank(final CharSequence cs) {
 		int strLen;
+		/* If string is null or length is 0 */
 		if (cs == null || (strLen = cs.length()) == 0) {
 			return true;
 		}
+		/* There should not be any white space character */
 		for (int i = 0; i < strLen; i++) {
 			if (Character.isWhitespace(cs.charAt(i)) == false) {
 				return false;
@@ -66,9 +71,11 @@ public static boolean isBlank(final CharSequence cs) {
 	 * @return {@link boolean}
 	 */
 	public static boolean isAnyBlank(final CharSequence... css) {
+		/* Input has to be array */
 		if (ArrayUtils.isEmpty(css)) {
 			return true;
 		}
+		/* Check for each character, if it is blank */
 		for (CharSequence cs : css) {
 			if (isBlank(cs)) {
 				return true;
@@ -84,6 +91,7 @@ public static boolean isAnyBlank(final CharSequence... css) {
 	 * @return {@link String}
 	 */
 	public static String trim(final String str) {
+		/* If string is null, return null else trim */
 		return str == null ? null : str.trim();
 	}
 
@@ -95,15 +103,80 @@ public static String trim(final String str) {
 	 * @return {@link String}
 	 */
 	public static String truncate(final String str, final int maxWidth) {
-		return str;
+		return truncate(str, 0, maxWidth);
 	}
 
+	/**
+	 * Method to truncate the string when max width 
+	 * and offset is given
+	 * 
+	 * @param str
+	 * @param offset
+	 * @param maxWidth
+	 * @return {@link String}
+	 */
+	public static String truncate(final String str, final int offset, final int maxWidth) {
+		/* Offset and max width can't be less then 0 */
+		if (offset < 0) {
+			throw new IllegalArgumentException("offset cannot be negative");
+		}
+		if (maxWidth < 0) {
+			throw new IllegalArgumentException("maxWidth cannot be negative");
+		}
+		/* If string is null, return null */
+		if (str == null) {
+			return null;
+		}
+		/* If offset is greater then list length, return empty string */
+		if (offset > str.length()) {
+			return "";
+		}
+		/* If valid scenario, find where we have to stop */
+		if (str.length() > maxWidth) {
+			final int ix = offset + maxWidth > str.length() ? str.length() : offset + maxWidth;
+			return str.substring(offset, ix);
+		}
+		return str.substring(offset);
+	}
+
+	/**
+	 * Method to check if two strings are equal
+	 * 
+	 * @param cs1
+	 * @param cs2
+	 * @return {@link boolean}
+	 */
 	public static boolean equals(final CharSequence cs1, final CharSequence cs2) {
+		/* If there reference is same, they are equal */
+		if (cs1 == cs2) {
+			return true;
+		}
+		/* If any one of them is null, they can't be equal */
+		if (cs1 == null || cs2 == null) {
+			return false;
+		}
+		/* If there lengths are different, they can't be equal */
+		if (cs1.length() != cs2.length()) {
+			return false;
+		}
+		/* Now, both of them has to be string and equal in value */
+		if (cs1 instanceof String && cs2 instanceof String) {
+			return cs1.equals(cs2);
+		}
 		return false;
 	}
 
+	/**
+	 * Method to check if two strings are equal when cases are ignored
+	 * 
+	 * @param str1
+	 * @param str2
+	 * @return {@link boolean}
+	 */
 	public static boolean equalsIgnoreCase(final CharSequence str1, final CharSequence str2) {
-		return false;
+		String updatedStr1 = String.valueOf(str1).toLowerCase();
+		String updatedStr2 = String.valueOf(str2).toLowerCase();
+		return equals(updatedStr1, updatedStr2);
 	}
 
 	public static int compare(final String str1, final String str2) {

test/com/deepak/data/structures/Utils/StringUtilsTest.java

@@ -80,4 +80,42 @@ public void testTrim() {
 		Assert.assertEquals(StringUtils.trim("    abc    "), "abc");
 	}
 
+	/**
+	 * Test case to check truncation of string
+	 */
+	@Test
+	public void testTruncate() {
+		Assert.assertEquals(StringUtils.truncate(null, 0), null);
+		Assert.assertEquals(StringUtils.truncate(null, 2), null);
+		Assert.assertEquals(StringUtils.truncate("", 4), "");
+		Assert.assertEquals(StringUtils.truncate("abcdefg", 4), "abcd");
+		Assert.assertEquals(StringUtils.truncate("abcdefg", 6), "abcdef");
+		Assert.assertEquals(StringUtils.truncate("abcdefg", 7), "abcdefg");
+		Assert.assertEquals(StringUtils.truncate("abcdefg", 8), "abcdefg");
+	}
+
+	/**
+	 * Method to test equals
+	 */
+	@Test
+	public void testEquals() {
+		Assert.assertTrue(StringUtils.equals(null, null));
+		Assert.assertTrue(StringUtils.equals("abc", "abc"));
+		Assert.assertFalse(StringUtils.equals(null, "abc"));
+		Assert.assertFalse(StringUtils.equals("abc", null));
+		Assert.assertFalse(StringUtils.equals("abc", "ABC"));
+	}
+
+	/**
+	 * Method to test equals ignore case 
+	 */
+	@Test
+	public void testEqualsIgnoreCase() {
+		Assert.assertTrue(StringUtils.equalsIgnoreCase(null, null));
+		Assert.assertTrue(StringUtils.equalsIgnoreCase("abc", "abc"));
+		Assert.assertFalse(StringUtils.equalsIgnoreCase(null, "abc"));
+		Assert.assertFalse(StringUtils.equalsIgnoreCase("abc", null));
+		Assert.assertTrue(StringUtils.equalsIgnoreCase("abc", "ABC"));
+	}
+
 }