Replace Guava Enum.getIfPresent with builtin version. (#4659)

* Replace Guava Enum.getIfPresent with builtin version.

This is useful for running in Hadoop environments that use Guava 11. Some
code is also simplified.

* Code review

codestyle/checkstyle.xml

@@ -110,7 +110,11 @@
       <property name="illegalPattern" value="true"/>
       <property name="message" value="Use Comparators.naturalNullsFirst() instead of Ordering.natural().nullsFirst()"/>
     </module>
-
+    <module name="Regexp">
+      <property name="format" value="Enums\.getIfPresent\("/>
+      <property name="illegalPattern" value="true"/>
+      <property name="message" value="Use GuavaUtils.getEnumIfPresent() instead of Enums.getIfPresent()"/>
+    </module>
     <module name="Regexp">
       <property name="format" value="(Byte|Character|Short|Integer|Long|Float|Double)\.TYPE"/>
       <property name="illegalPattern" value="true"/>

common/src/main/java/io/druid/common/guava/GuavaUtils.java

@@ -21,6 +21,7 @@ package io.druid.common.guava;
 
 import com.google.common.base.Charsets;
 import com.google.common.base.Function;
+import com.google.common.base.Preconditions;
 import com.google.common.base.Strings;
 import com.google.common.collect.Iterables;
 import com.google.common.io.CharStreams;
@@ -109,4 +110,26 @@ public class GuavaUtils
            ? null
            : Longs.tryParse(string.charAt(0) == '+' ? string.substring(1) : string);
   }
+
+  /**
+   * Like Guava's Enums.getIfPresent, with some differences.
+   * <ul>
+   * <li>Returns nullable rather than Optional</li>
+   * <li>Does not require Guava 12</li>
+   * </ul>
+   */
+  @Nullable
+  public static <T extends Enum<T>> T getEnumIfPresent(final Class<T> enumClass, final String value)
+  {
+    Preconditions.checkNotNull(enumClass, "enumClass");
+    Preconditions.checkNotNull(value, "value");
+
+    for (T enumValue : enumClass.getEnumConstants()) {
+      if (enumValue.name().equals(value)) {
+        return enumValue;
+      }
+    }
+
+    return null;
+  }
 }

common/src/test/java/io/druid/common/guava/GuavaUtilsTest.java

@@ -25,8 +25,15 @@ import org.junit.Test;
 
 public class GuavaUtilsTest
 {
+  enum MyEnum
+  {
+    ONE,
+    TWO,
+    BUCKLE_MY_SHOE
+  }
+
   @Test
-  public void testParsLong()
+  public void testParseLong()
   {
     Assert.assertNull(Longs.tryParse("+100"));
     Assert.assertNull(GuavaUtils.tryParseLong(""));
@@ -37,4 +44,13 @@ public class GuavaUtilsTest
     Assert.assertEquals((Object) Long.parseLong("-100"), GuavaUtils.tryParseLong("-100"));
     Assert.assertNotEquals(new Long(100), GuavaUtils.tryParseLong("+101"));
   }
+
+  @Test
+  public void testGetEnumIfPresent()
+  {
+    Assert.assertEquals(MyEnum.ONE, GuavaUtils.getEnumIfPresent(MyEnum.class, "ONE"));
+    Assert.assertEquals(MyEnum.TWO, GuavaUtils.getEnumIfPresent(MyEnum.class, "TWO"));
+    Assert.assertEquals(MyEnum.BUCKLE_MY_SHOE, GuavaUtils.getEnumIfPresent(MyEnum.class, "BUCKLE_MY_SHOE"));
+    Assert.assertEquals(null, GuavaUtils.getEnumIfPresent(MyEnum.class, "buckle_my_shoe"));
+  }
 }

processing/src/main/java/io/druid/query/groupby/GroupByQueryHelper.java

@@ -19,11 +19,11 @@
 
 package io.druid.query.groupby;
 
-import com.google.common.base.Enums;
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import io.druid.collections.NonBlockingPool;
+import io.druid.common.guava.GuavaUtils;
 import io.druid.data.input.MapBasedInputRow;
 import io.druid.data.input.MapBasedRow;
 import io.druid.data.input.Row;
@@ -245,7 +245,7 @@ public class GroupByQueryHelper
       final String typeName = aggregatorFactory.getTypeName();
       final ValueType valueType;
       if (typeName != null) {
-        valueType = Enums.getIfPresent(ValueType.class, StringUtils.toUpperCase(typeName)).orNull();
+        valueType = GuavaUtils.getEnumIfPresent(ValueType.class, StringUtils.toUpperCase(typeName));
       } else {
         valueType = null;
       }

processing/src/main/java/io/druid/segment/incremental/IncrementalIndex.java

@@ -20,7 +20,6 @@
 package io.druid.segment.incremental;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Enums;
 import com.google.common.base.Function;
 import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableList;
@@ -31,6 +30,7 @@ import com.google.common.collect.Maps;
 import com.google.common.primitives.Ints;
 import com.google.common.primitives.Longs;
 import io.druid.collections.NonBlockingPool;
+import io.druid.common.guava.GuavaUtils;
 import io.druid.data.input.InputRow;
 import io.druid.data.input.MapBasedRow;
 import io.druid.data.input.Row;
@@ -146,7 +146,7 @@ public abstract class IncrementalIndex<AggregatorType> implements Iterable<Row>,
 
         final ObjectColumnSelector rawColumnSelector = baseSelectorFactory.makeObjectColumnSelector(column);
 
-        if ((Enums.getIfPresent(ValueType.class, StringUtils.toUpperCase(typeName)).isPresent() && !typeName.equalsIgnoreCase(ValueType.COMPLEX.name()))
+        if ((GuavaUtils.getEnumIfPresent(ValueType.class, StringUtils.toUpperCase(typeName)) != null && !typeName.equalsIgnoreCase(ValueType.COMPLEX.name()))
             || !deserializeComplexMetrics) {
           return rawColumnSelector;
         } else {