Normalize times before comparison

fhirpath/src/main/java/au/csiro/pathling/sql/dates/datetime/DateTimeUDFRegistrar.java

@@ -33,7 +33,6 @@ protected void registerUDFs(final UDFRegistrar udfRegistrar) {
         .register(new DateTimeGreaterThanFunction())
         .register(new DateTimeGreaterThanOrEqualToFunction())
         .register(new DateTimeLessThanFunction())
-        .register(new DateTimeLessThanOrEqualToFunction())
-        .register(new NormalizeDateTimeFunction());
+        .register(new DateTimeLessThanOrEqualToFunction());
   }
 }

fhirpath/src/main/java/au/csiro/pathling/sql/dates/time/NormalizeTimeFunction.java

@@ -0,0 +1,39 @@
+package au.csiro.pathling.sql.dates.time;
+
+import au.csiro.pathling.sql.udf.SqlFunction1;
+import java.time.LocalTime;
+import java.time.temporal.ChronoUnit;
+import java.util.Objects;
+import org.apache.spark.sql.types.DataType;
+import org.apache.spark.sql.types.DataTypes;
+
+/**
+ * A function for normalizing a time string to a long (nanoseconds) for comparison purposes.
+ * <p>
+ * Truncates the precision of the time to milliseconds, as this is the highest precision supported
+ * by FHIR.
+ */
+public class NormalizeTimeFunction implements SqlFunction1<String, Long> {
+
+  private static final long serialVersionUID = 4117774962772392910L;
+
+  public static final String FUNCTION_NAME = "normalize_time";
+
+  @Override
+  public String getName() {
+    return FUNCTION_NAME;
+  }
+
+  @Override
+  public DataType getReturnType() {
+    return DataTypes.LongType;
+  }
+
+  @Override
+  public Long call(final String timeString) throws Exception {
+    final LocalTime time = Objects.requireNonNull(
+        LocalTime.parse(timeString));
+    return time.truncatedTo(ChronoUnit.MILLIS).toNanoOfDay();
+  }
+
+}

fhirpath/src/main/java/au/csiro/pathling/sql/misc/MiscUDFRegistrar.java

@@ -16,6 +16,8 @@
  */
 package au.csiro.pathling.sql.misc;
 
+import au.csiro.pathling.sql.dates.datetime.NormalizeDateTimeFunction;
+import au.csiro.pathling.sql.dates.time.NormalizeTimeFunction;
 import au.csiro.pathling.sql.udf.AbstractUDFRegistrar;
 
 /**
@@ -27,6 +29,8 @@ public class MiscUDFRegistrar extends AbstractUDFRegistrar {
   protected void registerUDFs(final UDFRegistrar udfRegistrar) {
     udfRegistrar
         .register(new CodingToLiteral())
-        .register(new TemporalDifferenceFunction());
+        .register(new TemporalDifferenceFunction())
+        .register(new NormalizeDateTimeFunction())
+        .register(new NormalizeTimeFunction());
   }
 }

fhirpath/src/test/java/au/csiro/pathling/views/FhirViewTest.java

@@ -18,6 +18,7 @@
 import au.csiro.pathling.encoders.datatypes.DecimalCustomCoder;
 import au.csiro.pathling.io.source.DataSource;
 import au.csiro.pathling.sql.dates.datetime.NormalizeDateTimeFunction;
+import au.csiro.pathling.sql.dates.time.NormalizeTimeFunction;
 import au.csiro.pathling.terminology.TerminologyServiceFactory;
 import au.csiro.pathling.test.SpringBootUnitTest;
 import ca.uhn.fhir.context.FhirContext;
@@ -142,6 +143,8 @@ class Expect implements ResultExpectation {
     public static final String FHIR_DATE_TIME_PATTERN = "^([0-9]([0-9]([0-9][1-9]|[1-9]0)|[1-9]00)|"
         + "[1-9]000)(-(0[1-9]|1[0-2])(-(0[1-9]|[1-2][0-9]|3[0-1])(T([01][0-9]|2[0-3]):[0-5][0-9]:"
         + "([0-5][0-9]|60)(\\.[0-9]{1,9})?)?)?(Z|(\\+|-)((0[0-9]|1[0-3]):[0-5][0-9]|14:00)?)?)?$";
+    public static final String FHIR_TIME_PATTERN = "^([01][0-9]|2[0-3]):[0-5][0-9]:([0-5][0-9]|60)"
+        + "(\\.[0-9]+)?$";
     Path expectedJson;
     List<String> expectedColumns;
 
@@ -166,6 +169,9 @@ public void expectResult(@Nonnull final Dataset<Row> rowDataset) {
               return when(
                   col(field.name()).rlike(FHIR_DATE_TIME_PATTERN),
                   callUDF(NormalizeDateTimeFunction.FUNCTION_NAME, col(field.name()))
+              ).when(
+                  col(field.name()).rlike(FHIR_TIME_PATTERN),
+                  callUDF(NormalizeTimeFunction.FUNCTION_NAME, col(field.name()))
               ).otherwise(col(field.name())).alias(field.name());
             } else {
               // Add the field to the selection without alteration.