Implement method for finding coarsest ZonedTimeGrain

yahoo · Apr 5, 2017 · fd99497 · fd99497
1 parent e78d748
commit fd99497
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diff --git a/fili-core/src/main/java/com/yahoo/bard/webservice/util/IntervalUtils.java b/fili-core/src/main/java/com/yahoo/bard/webservice/util/IntervalUtils.java
@@ -4,14 +4,19 @@
 
 import com.yahoo.bard.webservice.config.SystemConfig;
 import com.yahoo.bard.webservice.config.SystemConfigProvider;
+import com.yahoo.bard.webservice.data.time.ZonedTimeGrain;
 import com.yahoo.bard.webservice.druid.model.query.Granularity;
+import com.yahoo.bard.webservice.table.resolver.GranularityComparator;
 
 import org.joda.time.DateTime;
 import org.joda.time.Duration;
 import org.joda.time.Interval;
 import org.joda.time.base.AbstractInterval;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.Collection;
+import java.util.Comparator;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -30,6 +35,9 @@
  */
 public class IntervalUtils {
 
+    private static final Logger LOG = LoggerFactory.getLogger(IntervalUtils.class);
+    private static final GranularityComparator GRANULARITY_COMPARATOR = GranularityComparator.getInstance();
+
     public static final SystemConfig SYSTEM_CONFIG = SystemConfigProvider.getInstance();
 
     public static final String ALIGNMENT_EPOCH_STRING = SYSTEM_CONFIG.getStringProperty(
@@ -209,4 +217,20 @@ public static Optional<DateTime> firstMoment(Collection<? extends Collection<Int
                 .map(Interval::getStart)
                 .reduce(Utils::getMinValue);
     }
+
+    /**
+     * Returns the coarsest ZonedTimeGrain among a set of ZonedTimeGrains.
+     * <p>
+     * If the set of ZonedTimeGrains is empty, return null.
+     *
+     * @param zonedTimeGrains  A set of ZonedTimeGrains among which the coarsest ZonedTimeGrain is to be returned.
+     *
+     * @return the coarsest ZonedTimeGrain among a set of ZonedTimeGrains
+     */
+    public static ZonedTimeGrain getCoarsestTimeGrain(Collection<ZonedTimeGrain> zonedTimeGrains) {
+        return zonedTimeGrains.stream()
+                .sorted(Comparator.comparing(ZonedTimeGrain::getEstimatedDuration))
+                .findFirst()
+                .orElse(null);
+    }
 }
diff --git a/fili-core/src/test/groovy/com/yahoo/bard/webservice/util/IntervalUtilsSpec.groovy b/fili-core/src/test/groovy/com/yahoo/bard/webservice/util/IntervalUtilsSpec.groovy
@@ -7,11 +7,13 @@ import static com.yahoo.bard.webservice.data.time.DefaultTimeGrain.MONTH
 import static com.yahoo.bard.webservice.data.time.DefaultTimeGrain.WEEK
 import static com.yahoo.bard.webservice.data.time.DefaultTimeGrain.YEAR
 
+import com.yahoo.bard.webservice.data.time.ZonedTimeGrain
 import com.yahoo.bard.webservice.druid.model.query.AllGranularity
 import com.yahoo.bard.webservice.druid.model.query.Granularity
 
 import org.joda.time.DateTime
 import org.joda.time.DateTimeZone
+import org.joda.time.Duration
 import org.joda.time.Interval
 
 import spock.lang.Specification
@@ -326,6 +328,32 @@ class IntervalUtilsSpec extends Specification {
         DAY   | ["2012-02-03/2017-04-04"] | ["2012-02-03/2012-05-04", "2017-02-03/2017-04-04"]
     }
 
+    @Unroll
+    def "getCoarsestTimeGrain returns duration of #expected among #duration1, #duration2, #duration3"() {
+        given:
+        ZonedTimeGrain zonedTimeGrain1 = Mock(ZonedTimeGrain)
+        ZonedTimeGrain zonedTimeGrain2 = Mock(ZonedTimeGrain)
+        ZonedTimeGrain zonedTimeGrain3 = Mock(ZonedTimeGrain)
+
+        zonedTimeGrain1.getEstimatedDuration() >> new Duration(duration1)
+        zonedTimeGrain2.getEstimatedDuration() >> new Duration(duration2)
+        zonedTimeGrain3.getEstimatedDuration() >> new Duration(duration3)
+
+        expect:
+        IntervalUtils.getCoarsestTimeGrain([zonedTimeGrain1, zonedTimeGrain2, zonedTimeGrain3]).getEstimatedDuration().equals(new Duration(expected))
+
+        where:
+        duration1 | duration2 | duration3 | expected
+        1         | 2         | 3         | 1
+        1         | 1         | 3         | 1
+        3         | 3         | 3         | 3
+    }
+
+    def "getCoarsestTimeGrain returns null on empty input time grain collections"() {
+        expect:
+        IntervalUtils.getCoarsestTimeGrain(Collections.emptyList()) == null
+    }
+
     /**
      * Returns the instant at which this year began.
      *