Initial checkin of AOSP Messaging app.

b/23110861

Change-Id: I9aa980d7569247d6b2ca78f5dcb4502e1eaadb8a

src/com/android/messaging/util/TextUtil.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.messaging.util;
+
+import android.support.annotation.Nullable;
+
+public class TextUtil {
+    /**
+     * Returns true if the string is empty, null or only whitespace.
+     */
+    public static boolean isAllWhitespace(@Nullable String string) {
+      if (string == null || string.isEmpty()) {
+        return true;
+      }
+
+      for (int i = 0; i < string.length(); ++i) {
+        if (!Character.isWhitespace(string.charAt(i))) {
+          return false;
+        }
+      }
+
+      return true;
+    }
+
+    /**
+     * Taken from PhoneNumberUtils, where it is only available in API 21+ Replaces all unicode
+     * (e.g. Arabic, Persian) digits with their decimal digit equivalents.
+     *
+     * @param number the number to perform the replacement on.
+     * @return the replaced number.
+     */
+    public static String replaceUnicodeDigits(String number) {
+        StringBuilder normalizedDigits = new StringBuilder(number.length());
+        for (char c : number.toCharArray()) {
+            int digit = Character.digit(c, 10);
+            if (digit != -1) {
+                normalizedDigits.append(digit);
+            } else {
+                normalizedDigits.append(c);
+            }
+        }
+        return normalizedDigits.toString();
+    }
+
+    /**
+     * Appends text to the stringBuilder.
+     * If stringBuilder already has content, separator is prepended to create a separator between
+     * entries.
+     * @param stringBuilder The stringBuilder to add to
+     * @param text The text to append
+     * @param separator The separator to add if there is already text, typically "," or "\n"
+     */
+    public static void appendWithSeparator(final StringBuilder stringBuilder, final String text,
+            final String separator) {
+        if (stringBuilder.length() > 0) {
+            stringBuilder.append(separator);
+        }
+        stringBuilder.append(text);
+    }
+}