1 files changed, 42 insertions, 0 deletions
diff --git a/api/src/main/java/io/opencensus/internal/StringUtils.java b/api/src/main/java/io/opencensus/internal/StringUtils.java
new file mode 100644
index 00000000..717e333c
--- /dev/null
+++ b/api/src/main/java/io/opencensus/internal/StringUtils.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2016-17, OpenCensus Authors
+ *
+ * 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 io.opencensus.internal;
+
+/** Internal utility methods for working with tag keys, tag values, and metric names. */
+public final class StringUtils {
+
+  /**
+   * Determines whether the {@code String} contains only printable characters.
+   *
+   * @param str the {@code String} to be validated.
+   * @return whether the {@code String} contains only printable characters.
+   */
+  public static boolean isPrintableString(String str) {
+    for (int i = 0; i < str.length(); i++) {
+      if (!isPrintableChar(str.charAt(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  private static boolean isPrintableChar(char ch) {
+    return ch >= ' ' && ch <= '~';
+  }
+
+  private StringUtils() {}
+}