[SPARK-8938][SQL] Implement toString for Interval data type

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #7315 from cloud-fan/toString and squashes the following commits:

4fc8d80 [Wenchen Fan] Implement toString for Interval data type

2 files changed, 101 insertions, 0 deletions

diff --git a/unsafe/src/main/java/org/apache/spark/unsafe/types/Interval.java b/unsafe/src/main/java/org/apache/spark/unsafe/types/Interval.java
index 3eb67ede06..0af982d484 100644
--- a/unsafe/src/main/java/org/apache/spark/unsafe/types/Interval.java
+++ b/unsafe/src/main/java/org/apache/spark/unsafe/types/Interval.java
@@ -23,6 +23,13 @@ import java.io.Serializable;
  * The internal representation of interval type.
  */
 public final class Interval implements Serializable {
+  public static final long MICROS_PER_MILLI = 1000L;
+  public static final long MICROS_PER_SECOND = MICROS_PER_MILLI * 1000;
+  public static final long MICROS_PER_MINUTE = MICROS_PER_SECOND * 60;
+  public static final long MICROS_PER_HOUR = MICROS_PER_MINUTE * 60;
+  public static final long MICROS_PER_DAY = MICROS_PER_HOUR * 24;
+  public static final long MICROS_PER_WEEK = MICROS_PER_DAY * 7;
+
   public final int months;
   public final long microseconds;
 
@@ -44,4 +51,39 @@ public final class Interval implements Serializable {
   public int hashCode() {
     return 31 * months + (int) microseconds;
   }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder("interval");
+
+    if (months != 0) {
+      appendUnit(sb, months / 12, "year");
+      appendUnit(sb, months % 12, "month");
+    }
+
+    if (microseconds != 0) {
+      long rest = microseconds;
+      appendUnit(sb, rest / MICROS_PER_WEEK, "week");
+      rest %= MICROS_PER_WEEK;
+      appendUnit(sb, rest / MICROS_PER_DAY, "day");
+      rest %= MICROS_PER_DAY;
+      appendUnit(sb, rest / MICROS_PER_HOUR, "hour");
+      rest %= MICROS_PER_HOUR;
+      appendUnit(sb, rest / MICROS_PER_MINUTE, "minute");
+      rest %= MICROS_PER_MINUTE;
+      appendUnit(sb, rest / MICROS_PER_SECOND, "second");
+      rest %= MICROS_PER_SECOND;
+      appendUnit(sb, rest / MICROS_PER_MILLI, "millisecond");
+      rest %= MICROS_PER_MILLI;
+      appendUnit(sb, rest, "microsecond");
+    }
+
+    return sb.toString();
+  }
+
+  private void appendUnit(StringBuilder sb, long value, String unit) {
+    if (value != 0) {
+      sb.append(" " + value + " " + unit + "s");
+    }
+  }
 }
diff --git a/unsafe/src/test/java/org/apache/spark/unsafe/types/IntervalSuite.java b/unsafe/src/test/java/org/apache/spark/unsafe/types/IntervalSuite.java
new file mode 100644
index 0000000000..0f4f38b2b0
--- /dev/null
+++ b/unsafe/src/test/java/org/apache/spark/unsafe/types/IntervalSuite.java
@@ -0,0 +1,59 @@
+/*
+* Licensed to the Apache Software Foundation (ASF) under one or more
+* contributor license agreements.  See the NOTICE file distributed with
+* this work for additional information regarding copyright ownership.
+* The ASF licenses this file to You 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 org.apache.spark.unsafe.types;
+
+import org.junit.Test;
+
+import static junit.framework.Assert.*;
+import static org.apache.spark.unsafe.types.Interval.*;
+
+public class IntervalSuite {
+
+  @Test
+  public void equalsTest() {
+    Interval i1 = new Interval(3, 123);
+    Interval i2 = new Interval(3, 321);
+    Interval i3 = new Interval(1, 123);
+    Interval i4 = new Interval(3, 123);
+
+    assertNotSame(i1, i2);
+    assertNotSame(i1, i3);
+    assertNotSame(i2, i3);
+    assertEquals(i1, i4);
+  }
+
+  @Test
+  public void toStringTest() {
+    Interval i;
+
+    i = new Interval(34, 0);
+    assertEquals(i.toString(), "interval 2 years 10 months");
+
+    i = new Interval(-34, 0);
+    assertEquals(i.toString(), "interval -2 years -10 months");
+
+    i = new Interval(0, 3 * MICROS_PER_WEEK + 13 * MICROS_PER_HOUR + 123);
+    assertEquals(i.toString(), "interval 3 weeks 13 hours 123 microseconds");
+
+    i = new Interval(0, -3 * MICROS_PER_WEEK - 13 * MICROS_PER_HOUR - 123);
+    assertEquals(i.toString(), "interval -3 weeks -13 hours -123 microseconds");
+
+    i = new Interval(34, 3 * MICROS_PER_WEEK + 13 * MICROS_PER_HOUR + 123);
+    assertEquals(i.toString(), "interval 2 years 10 months 3 weeks 13 hours 123 microseconds");
+  }
+}