some common string utils added

src/main/java/ru/touchin/roboswag/core/utils/StringUtils.java

@@ -0,0 +1,85 @@
+package ru.touchin.roboswag.core.utils;
+
+import android.support.annotation.NonNull;
+
+import java.security.MessageDigest;
+
+import rx.functions.Func1;
+
+public class StringUtils {
+
+    /**
+     * Returns MD5 of string.
+     *
+     * @param string String to get MD5 from;
+     * @return MD5 of string.
+     */
+    @NonNull
+    public static String md5(@NonNull final String string) {
+        try {
+            final MessageDigest digest = MessageDigest.getInstance("MD5");
+            digest.update(string.getBytes("UTF-8"));
+            final byte[] messageDigestArray = digest.digest();
+
+            final StringBuilder hexString = new StringBuilder();
+            for (final byte messageDigest : messageDigestArray) {
+                final String hex = Integer.toHexString(0xFF & messageDigest);
+                if (hex.length() == 1) {
+                    hexString.append('0');
+                }
+                hexString.append(hex);
+            }
+            return hexString.toString();
+        } catch (final Exception exception) {
+            throw new ShouldNotHappenException(exception);
+        }
+    }
+
+    /**
+     * Returns true if input text contains character satisfies condition.
+     *
+     * @param text      Text to check characters;
+     * @param condition Condition of symbol;
+     * @return True if some character satisfies condition.
+     */
+    public static boolean containsCharLike(@NonNull final String text, @NonNull final Func1<Character, Boolean> condition) {
+        for (int i = 0; i < text.length(); i++) {
+            if (condition.call(text.charAt(i))) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns if text contains any number.
+     *
+     * @param text Text to check;
+     * @return True if there are any number in text.
+     */
+    public static boolean containsNumbers(@NonNull final String text) {
+        return containsCharLike(text, Character::isDigit);
+    }
+
+    /**
+     * Returns if text contains any lower-case character.
+     *
+     * @param text Text to check;
+     * @return True if there are any lower-case character in text.
+     */
+    public static boolean containsLowerCase(@NonNull final String text) {
+        return containsCharLike(text, Character::isLowerCase);
+    }
+
+    /**
+     * Returns if text contains any upper-case character.
+     *
+     * @param text Text to check;
+     * @return True if there are any upper-case character in text.
+     */
+    public static boolean containsUpperCase(@NonNull final String text) {
+        return containsCharLike(text, Character::isUpperCase);
+    }
+
+
+}