Removes 'Tag' and moves its utility methods to a 'StringSanitization' class.

Author: sebright2

BUILD

@@ -162,8 +162,8 @@ java_test(
 )
 
 java_test(
-    name = "TagKeyTest",
-    srcs = ["core/javatests/com/google/census/TagKeyTest.java"],
+    name = "StringSanitizationTest",
+    srcs = ["core/javatests/com/google/census/StringSanitizationTest.java"],
     deps = [
         ":census-core",
         ":census-core_native",
@@ -176,8 +176,8 @@ java_test(
 )
 
 java_test(
-    name = "TagTest",
-    srcs = ["core/javatests/com/google/census/TagTest.java"],
+    name = "TagKeyTest",
+    srcs = ["core/javatests/com/google/census/TagKeyTest.java"],
     deps = [
         ":census-core",
         ":census-core_native",

core/java/com/google/census/MetricName.java

@@ -19,10 +19,10 @@
  * MetricName's are {@link String}s with enforced restrictions.
  */
 public final class MetricName {
-  public static final int MAX_LENGTH = Tag.MAX_LENGTH;
+  public static final int MAX_LENGTH = StringSanitization.MAX_LENGTH;
 
   public MetricName(String name) {
-    this.name = Tag.sanitize(name);
+    this.name = StringSanitization.sanitize(name);
   }
 
   @Override

core/java/com/google/census/Tag.java …om/google/census/StringSanitization.javacore/java/com/google/census/Tag.java renamed to core/java/com/google/census/StringSanitization.java core/java/com/google/census/Tag.java renamed to core/java/com/google/census/StringSanitization.java

@@ -13,52 +13,10 @@
 
 package com.google.census;
 
-import java.util.Map.Entry;
-
 /**
- * Immutable representation of a Tag.
+ * Utility methods for sanitizing tag keys, tag values, and metric names.
  */
-public class Tag implements Entry<String, String> {
-
-  public Tag(TagKey key, TagValue value) {
-    this.key = key.toString();
-    this.value = value.toString();
-  }
-
-  @Override
-  public String getKey() {
-    return key;
-  }
-
-  @Override
-  public String getValue() {
-    return value;
-  }
-
-  @Override
-  public String setValue(String value) {
-    throw new UnsupportedOperationException();
-  }
-
-  @Override
-  public boolean equals(Object obj) {
-    if (!(obj instanceof Tag)) {
-      return false;
-    }
-    Tag that = (Tag) obj;
-    return key.equals(that.key) && value.equals(that.value);
-  }
-
-  @Override
-  public int hashCode() {
-    return key.hashCode() * 31 + value.hashCode();
-  }
-
-  // Assumes key and value have already been sanitized.
-  Tag(String key, String value) {
-    this.key = key;
-    this.value = value;
-  }
+final class StringSanitization {
 
   static final int MAX_LENGTH = 255;
   static final char UNPRINTABLE_CHAR_SUBSTITUTE = '_';
@@ -91,6 +49,8 @@ private static boolean isPrintableChar(char c) {
     return c >= ' ' && c <= '~';
   }
 
-  private final String key;
-  private final String value;
+  //Visible for testing
+  StringSanitization() {
+    throw new AssertionError();
+  }
 }

core/java/com/google/census/TagKey.java

@@ -19,10 +19,10 @@
  * TagKey's are {@link String}s with enforced restrictions.
  */
 public final class TagKey {
-  public static final int MAX_LENGTH = Tag.MAX_LENGTH;
+  public static final int MAX_LENGTH = StringSanitization.MAX_LENGTH;
 
   public TagKey(String key) {
-    this.key = Tag.sanitize(key);
+    this.key = StringSanitization.sanitize(key);
   }
 
   @Override

core/java/com/google/census/TagValue.java

@@ -19,10 +19,10 @@
  * TagValue's are {@link String}s with enforced restrictions.
  */
 public final class TagValue {
-  public static final int MAX_LENGTH = Tag.MAX_LENGTH;
+  public static final int MAX_LENGTH = StringSanitization.MAX_LENGTH;
 
   public TagValue(String value) {
-    this.value = Tag.sanitize(value);
+    this.value = StringSanitization.sanitize(value);
   }
 
   @Override

core/javatests/com/google/census/MetricNameTest.java

@@ -39,7 +39,8 @@ public void testNameMaxLength() {
   @Test
   public void testNameBadChar() {
     assertThat(new MetricName("\2ab\3cd").toString())
-        .isEqualTo(Tag.UNPRINTABLE_CHAR_SUBSTITUTE + "ab" + Tag.UNPRINTABLE_CHAR_SUBSTITUTE + "cd");
+        .isEqualTo(StringSanitization.UNPRINTABLE_CHAR_SUBSTITUTE + "ab"
+                 + StringSanitization.UNPRINTABLE_CHAR_SUBSTITUTE + "cd");
   }
 
   @Test

core/javatests/com/google/census/StringSanitizationTest.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2016, Google Inc.
+ * 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.google.census;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.util.Arrays;
+import org.junit.Test;
+
+public class StringSanitizationTest {
+  @Test
+  public void testMaxLength() {
+    char[] string = new char[StringSanitization.MAX_LENGTH];
+    char[] truncString = new char[StringSanitization.MAX_LENGTH + 10];
+    Arrays.fill(string, 'v');
+    Arrays.fill(truncString, 'v');
+    assertThat(StringSanitization.sanitize(new String(truncString))).isEqualTo(new String(string));
+  }
+
+  @Test
+  public void testBadChar() {
+    String string = "\2ab\3cd";
+    assertThat(StringSanitization.sanitize(string).toString()).isEqualTo("_ab_cd");
+  }
+
+  @Test(expected=AssertionError.class)
+  public void testConstructor() {
+    new StringSanitization();
+  }
+}

core/javatests/com/google/census/TagKeyTest.java

@@ -41,7 +41,8 @@ public void testKeyMaxLength() {
   public void testKeyBadChar() {
     String key = "\2ab\3cd";
     assertThat(new TagKey(key).toString())
-        .isEqualTo(Tag.UNPRINTABLE_CHAR_SUBSTITUTE + "ab" + Tag.UNPRINTABLE_CHAR_SUBSTITUTE + "cd");
+        .isEqualTo(StringSanitization.UNPRINTABLE_CHAR_SUBSTITUTE + "ab"
+                 + StringSanitization.UNPRINTABLE_CHAR_SUBSTITUTE + "cd");
   }
 
   @Test

core/javatests/com/google/census/TagValueTest.java

@@ -40,7 +40,8 @@ public void testValueMaxLength() {
   public void testValueBadChar() {
     String value = "\2ab\3cd";
     assertThat(new TagValue(value).toString())
-        .isEqualTo(Tag.UNPRINTABLE_CHAR_SUBSTITUTE + "ab" + Tag.UNPRINTABLE_CHAR_SUBSTITUTE + "cd");
+        .isEqualTo(StringSanitization.UNPRINTABLE_CHAR_SUBSTITUTE + "ab"
+                 + StringSanitization.UNPRINTABLE_CHAR_SUBSTITUTE + "cd");
   }
 
   @Test