Moving string utils methods to a utils class

app/src/main/java/acr/browser/lightning/utils/AdBlock.java

@@ -154,24 +154,26 @@ public class AdBlock {
                     while ((line = reader.readLine()) != null) {
                         lineBuilder.append(line);
 
-                        if (!isEmpty(lineBuilder) && !startsWith(lineBuilder, COMMENT)) {
-                            replace(lineBuilder, LOCAL_IP_V4, EMPTY);
-                            replace(lineBuilder, LOCAL_IP_V4_ALT, EMPTY);
-                            replace(lineBuilder, LOCAL_IP_V6, EMPTY);
-                            replace(lineBuilder, TAB, EMPTY);
+                        if (!StringBuilderUtils.isEmpty(lineBuilder) &&
+                            !StringBuilderUtils.startsWith(lineBuilder, COMMENT)) {
+                            StringBuilderUtils.replace(lineBuilder, LOCAL_IP_V4, EMPTY);
+                            StringBuilderUtils.replace(lineBuilder, LOCAL_IP_V4_ALT, EMPTY);
+                            StringBuilderUtils.replace(lineBuilder, LOCAL_IP_V6, EMPTY);
+                            StringBuilderUtils.replace(lineBuilder, TAB, EMPTY);
 
                             int comment = lineBuilder.indexOf(COMMENT);
                             if (comment >= 0) {
                                 lineBuilder.replace(comment, lineBuilder.length(), EMPTY);
                             }
 
-                            trim(lineBuilder);
+                            StringBuilderUtils.trim(lineBuilder);
 
-                            if (!isEmpty(lineBuilder) && !AdBlock.equals(lineBuilder, LOCALHOST)) {
-                                while (contains(lineBuilder, SPACE)) {
+                            if (!StringBuilderUtils.isEmpty(lineBuilder) &&
+                                !StringBuilderUtils.equals(lineBuilder, LOCALHOST)) {
+                                while (StringBuilderUtils.contains(lineBuilder, SPACE)) {
                                     int space = lineBuilder.indexOf(SPACE);
                                     String host = lineBuilder.substring(0, space);
-                                    replace(lineBuilder, host, EMPTY);
+                                    StringBuilderUtils.replace(lineBuilder, host, EMPTY);
                                     mBlockedDomainsList.add(host.trim());
                                 }
                                 if (lineBuilder.length() > 0) {
@@ -192,40 +194,4 @@ public class AdBlock {
         });
     }
 
-    // TODO: 4/23/17 Move all these methods to a StringUtils class
-    private static void replace(@NonNull StringBuilder stringBuilder,
-                                @NonNull String toReplace,
-                                @NonNull String replacement) {
-        int index = stringBuilder.indexOf(toReplace);
-        if (index >= 0) {
-            stringBuilder.replace(index, index + toReplace.length(), replacement);
-        }
-    }
-
-    private static void trim(@NonNull StringBuilder stringBuilder) {
-        while (stringBuilder.indexOf(SPACE) == 0) {
-            stringBuilder.replace(0, 1, EMPTY);
-        }
-
-        while (stringBuilder.lastIndexOf(SPACE) == (stringBuilder.length() - 1)) {
-            stringBuilder.replace(stringBuilder.length() - 1, stringBuilder.length(), EMPTY);
-        }
-    }
-
-    private static boolean isEmpty(@NonNull StringBuilder stringBuilder) {
-        return stringBuilder.length() == 0;
-    }
-
-    private static boolean startsWith(@NonNull StringBuilder stringBuilder, @NonNull String start) {
-        return stringBuilder.indexOf(start) == 0;
-    }
-
-    private static boolean contains(@NonNull StringBuilder stringBuilder, @NonNull String contains) {
-        return stringBuilder.indexOf(contains) >= 0;
-    }
-
-    private static boolean equals(@NonNull StringBuilder stringBuilder, @NonNull String equal) {
-        int index = stringBuilder.indexOf(equal);
-        return index >= 0 && stringBuilder.length() == equal.length();
-    }
 }

app/src/main/java/acr/browser/lightning/utils/StringBuilderUtils.java

@@ -0,0 +1,99 @@
+package acr.browser.lightning.utils;
+
+import android.support.annotation.NonNull;
+
+/**
+ * A collection of utils methods for
+ * {@link StringBuilder} that provides
+ * API equality with the {@link String}
+ * API.
+ */
+public class StringBuilderUtils {
+
+    private static final String SPACE = " ";
+    private static final String EMPTY = "";
+
+    /**
+     * Replace a string in a string
+     * builder with another string.
+     *
+     * @param stringBuilder the string builder.
+     * @param toReplace     the string to replace.
+     * @param replacement   the replacement string.
+     */
+    public static void replace(@NonNull StringBuilder stringBuilder,
+                               @NonNull String toReplace,
+                               @NonNull String replacement) {
+        int index = stringBuilder.indexOf(toReplace);
+        if (index >= 0) {
+            stringBuilder.replace(index, index + toReplace.length(), replacement);
+        }
+    }
+
+    /**
+     * Trims a string builder of
+     * any spaces at the beginning
+     * and end.
+     *
+     * @param stringBuilder the string builder.
+     */
+    public static void trim(@NonNull StringBuilder stringBuilder) {
+        while (stringBuilder.indexOf(SPACE) == 0) {
+            stringBuilder.replace(0, 1, EMPTY);
+        }
+
+        while (stringBuilder.lastIndexOf(SPACE) == (stringBuilder.length() - 1)) {
+            stringBuilder.replace(stringBuilder.length() - 1, stringBuilder.length(), EMPTY);
+        }
+    }
+
+    /**
+     * Determines if the string builder is empty.
+     *
+     * @param stringBuilder the string builder.
+     * @return true if the string builder is empty,
+     * false otherwise.
+     */
+    public static boolean isEmpty(@NonNull StringBuilder stringBuilder) {
+        return stringBuilder.length() == 0;
+    }
+
+    /**
+     * Determines if a string builder starts with
+     * a specific string.
+     *
+     * @param stringBuilder the string builder.
+     * @param start         the starting string.
+     * @return true if the string builder starts
+     * with the string, false otherwise.
+     */
+    public static boolean startsWith(@NonNull StringBuilder stringBuilder, @NonNull String start) {
+        return stringBuilder.indexOf(start) == 0;
+    }
+
+    /**
+     * Determines if a string builder contains a string.
+     *
+     * @param stringBuilder the string builder.
+     * @param contains      the string that it might contain.
+     * @return true if the string builder contains the
+     * string, false otherwise.
+     */
+    public static boolean contains(@NonNull StringBuilder stringBuilder, @NonNull String contains) {
+        return stringBuilder.indexOf(contains) >= 0;
+    }
+
+    /**
+     * Determines equality between a string
+     * builder and a string.
+     *
+     * @param stringBuilder the string builder.
+     * @param equal         the string.
+     * @return true if the string represented by
+     * the string builder is equal to the string.
+     */
+    public static boolean equals(@NonNull StringBuilder stringBuilder, @NonNull String equal) {
+        int index = stringBuilder.indexOf(equal);
+        return index >= 0 && stringBuilder.length() == equal.length();
+    }
+}