[NEw] New util CodeGenerator

li.strolch.utils/src/main/java/li/strolch/utils/CodeGenerator.java

@@ -0,0 +1,36 @@
+package li.strolch.utils;
+
+import java.security.SecureRandom;
+
+/**
+ * Generates code which should be easily readable as problematic letters e.g. 0, o, O, i, I, l are left out
+ * 
+ * @author Robert von Burg <eitch@eitchnet.ch>
+ */
+public class CodeGenerator {
+
+	private static final String ALPHA_NUMERIC_UPPER = "123456789ABCDEFGHJKLMNPQRSTUVWXYZ";
+	private static final String ALPHA_NUMERIC_LOWER_UPPER = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjklmnpqrstuvwxyz";
+
+	public static String alphaNumericUpper(int len) {
+
+		SecureRandom rnd = new SecureRandom();
+
+		StringBuilder sb = new StringBuilder(len);
+		for (int i = 0; i < len; i++)
+			sb.append(ALPHA_NUMERIC_UPPER.charAt(rnd.nextInt(ALPHA_NUMERIC_UPPER.length())));
+
+		return sb.toString();
+	}
+
+	public static String alphaNumericLowerUpper(int len) {
+
+		SecureRandom rnd = new SecureRandom();
+
+		StringBuilder sb = new StringBuilder(len);
+		for (int i = 0; i < len; i++)
+			sb.append(ALPHA_NUMERIC_LOWER_UPPER.charAt(rnd.nextInt(ALPHA_NUMERIC_LOWER_UPPER.length())));
+
+		return sb.toString();
+	}
+}

li.strolch.utils/src/test/java/li/strolch/utils/CodeGeneratorTest.java

@@ -0,0 +1,39 @@
+package li.strolch.utils;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class CodeGeneratorTest {
+
+	@Test
+	public void shouldCreateGeneratorLowerUpper() {
+		String code = CodeGenerator.alphaNumericLowerUpper(12);
+		assertEquals(12, code.length());
+		assertFalse(code.contains("0"));
+		assertFalse(code.contains("i"));
+		assertFalse(code.contains("I"));
+		assertFalse(code.contains("l"));
+		assertFalse(code.contains("o"));
+		assertFalse(code.contains("O"));
+	}
+
+	@Test
+	public void shouldCreateGeneratorUpper() {
+		String code = CodeGenerator.alphaNumericUpper(500);
+		assertEquals(500, code.length());
+		assertFalse(code.contains("0"));
+		assertFalse(code.contains("i"));
+		assertFalse(code.contains("I"));
+		assertFalse(code.contains("l"));
+		assertFalse(code.contains("o"));
+		assertFalse(code.contains("O"));
+
+		for (int i = 0; i < code.length(); i++) {
+			char c = code.charAt(i);
+			assertTrue(Character.isDigit(c) || Character.isUpperCase(c));
+		}
+	}
+}