Refactor, simplify Measurement & rename cause

src/main/java/com/microsoft/dhalion/core/Measurement.java

@@ -11,17 +11,19 @@ import java.time.Instant;
 /**
  * A {@link Measurement} is value of a metric corresponding to an instance at a instant of time.
  */
-public abstract class Measurement {
+public class Measurement {
   private final String component;
   private final String instance;
   private final String type;
   private final long instantMillis; // UTC
+  private final double value;
 
-  private Measurement(String component, String instance, String type, Instant instant) {
+  public Measurement(String component, String instance, String type, Instant instant, double value) {
     this.component = component;
     this.instance = instance;
     this.type = type;
     this.instantMillis = instant.toEpochMilli();
+    this.value = value;
   }
 
   public String component() {
@@ -40,40 +42,31 @@ public abstract class Measurement {
     return Instant.ofEpochMilli(instantMillis);
   }
 
-  public static class ScalarMeasurement extends Measurement {
+  public double value() {
-    private final double value;
+    return value;
+  }
 
-    public ScalarMeasurement(String component, String instance, String metricType, Instant instant, double value) {
+  @Override
-      super(component, instance, metricType, instant);
+  public String toString() {
-      this.value = value;
+    return "Measurement {" +
-    }
+        "component=" + component() +
-
+        ", instance=" + instance() +
-    public double value() {
+        ", type=" + type() +
-      return value;
+        ", instant=" + instant() +
-    }
+        ", value=" + value +
-
+        '}';
-    @Override
-    public String toString() {
-      return "Measurement {" +
-          "component=" + component() +
-          ", instance=" + instance() +
-          ", type=" + type() +
-          ", instant=" + instant() +
-          ", value=" + value +
-          '}';
-    }
   }
 
   public static class ObjMeasurement extends Measurement {
-    private final Object value;
+    private final Object reference;
 
     public ObjMeasurement(String component, String instance, String metricType, Instant instant, Object value) {
-      super(component, instance, metricType, instant);
+      super(component, instance, metricType, instant, 0);
-      this.value = value;
+      this.reference = value;
     }
 
-    public Object value() {
+    public Object reference() {
-      return value;
+      return reference;
     }
   }
 }

src/main/java/com/microsoft/dhalion/core/MeasurementsArray.java

@@ -6,7 +6,6 @@
  */
 package com.microsoft.dhalion.core;
 
-import com.microsoft.dhalion.core.Measurement.ScalarMeasurement;
 import tech.tablesaw.api.CategoryColumn;
 import tech.tablesaw.api.DoubleColumn;
 import tech.tablesaw.api.LongColumn;
@@ -81,7 +80,7 @@ public class MeasurementsArray {
       instance.append(measurement.instance());
       type.append(measurement.type());
       timeStamps.append(measurement.instant().toEpochMilli());
-      value.append(((ScalarMeasurement) measurement).value());
+      value.append(measurement.value());
     });
   }
 
@@ -326,11 +325,11 @@ public class MeasurementsArray {
   public Collection<Measurement> get() {
     ArrayList<Measurement> result = new ArrayList<>();
     for (int i = 0; i < measurements.rowCount(); i++) {
-      result.add(new ScalarMeasurement(component.get(i),
+      result.add(new Measurement(component.get(i),
-                                       instance.get(i),
+                                 instance.get(i),
-                                       type.get(i),
+                                 type.get(i),
-                                       Instant.ofEpochMilli(timeStamps.get(i)),
+                                 Instant.ofEpochMilli(timeStamps.get(i)),
-                                       value.get(i)));
+                                 value.get(i)));
     }
     return result;
   }

src/main/java/com/microsoft/dhalion/core/Symptom.java

@@ -27,18 +27,18 @@ public class Symptom {
   // instant when this symptom was created
   private final Instant instant;
 
-  // cause identifiers
+  // ids to which the symptom is assigned, for e.g. instances
-  private final Collection<String> causeIds;
+  private final Collection<String> assignments;
 
-  public Symptom(String symptomType, Instant instant, Collection<String> causeIds) {
+  public Symptom(String symptomType, Instant instant, Collection<String> assignments) {
-    this(idGenerator.incrementAndGet(), symptomType, instant, causeIds);
+    this(idGenerator.incrementAndGet(), symptomType, instant, assignments);
   }
 
-  public Symptom(int id, String symptomType, Instant instant, Collection<String> causeIds) {
+  public Symptom(int id, String symptomType, Instant instant, Collection<String> assignments) {
+    this.id = id;
     this.type = symptomType;
     this.instant = instant;
-    this.causeIds = new ArrayList<>(causeIds);
+    this.assignments = new ArrayList<>(assignments);
-    this.id = id;
   }
 
   public int id() {
@@ -53,8 +53,8 @@ public class Symptom {
     return instant;
   }
 
-  public Collection<String> causeIds() {
+  public Collection<String> assignments() {
-    return causeIds;
+    return assignments;
   }
 
   @Override
@@ -63,7 +63,7 @@ public class Symptom {
         "type=" + type +
         ", id=" + id +
         ", instant=" + instant +
-        ", causeIds=" + causeIds +
+        ", assignments=" + assignments +
         '}';
   }
 }

src/main/java/com/microsoft/dhalion/core/SymptomsArray.java

@@ -36,27 +36,27 @@ public class SymptomsArray {
   private final Table symptoms;
   private CategoryColumn type;
   private IntColumn id;
-  private CategoryColumn cause;
+  private CategoryColumn assignment;
   private LongColumn timeStamp;
 
   public enum SortKey {
-    ID, CAUSE, TIME_STAMP, TYPE
+    ID, ASSIGNMENT, TIME_STAMP, TYPE
   }
 
   private static final String ID = SortKey.ID.name();
-  private static final String CAUSE = SortKey.CAUSE.name();
+  private static final String ASSIGNMENT = SortKey.ASSIGNMENT.name();
   private static final String TIME_STAMP = SortKey.TIME_STAMP.name();
   private static final String TYPE = SortKey.TYPE.name();
 
   private SymptomsArray() {
     id = new IntColumn(ID);
-    cause = new CategoryColumn(CAUSE);
+    assignment = new CategoryColumn(ASSIGNMENT);
     type = new CategoryColumn(TYPE);
     timeStamp = new LongColumn(TIME_STAMP);
 
     symptoms = Table.create("Symptoms");
     symptoms.addColumn(id);
-    symptoms.addColumn(cause);
+    symptoms.addColumn(assignment);
     symptoms.addColumn(type);
     symptoms.addColumn(timeStamp);
   }
@@ -64,16 +64,16 @@ public class SymptomsArray {
   private SymptomsArray(Table table) {
     this.symptoms = table;
     id = symptoms.intColumn(ID);
-    cause = symptoms.categoryColumn(CAUSE);
+    assignment = symptoms.categoryColumn(ASSIGNMENT);
     type = symptoms.categoryColumn(TYPE);
     timeStamp = symptoms.longColumn(TIME_STAMP);
   }
 
   private void addAll(Collection<Symptom> symptoms) {
     symptoms.forEach(symptom -> {
-      symptom.causeIds().forEach(causeId -> {
+      symptom.assignments().forEach(assignment -> {
         id.append(symptom.id());
-        cause.append(causeId);
+        this.assignment.append(assignment);
         type.append(symptom.type());
         timeStamp.append(symptom.instant().toEpochMilli());
       });
@@ -109,22 +109,22 @@ public class SymptomsArray {
   }
 
   /**
-   * Retains all {@link Symptom}s with given cause ids.
+   * Retains all {@link Symptom}s with given assignment ids.
    *
-   * @param causeIds cause ids, not null
+   * @param assignments assignment ids, not null
    * @return {@link SymptomsArray} containing filtered {@link Symptom}s
    */
-  public SymptomsArray cause(Collection<String> causeIds) {
+  public SymptomsArray assignment(Collection<String> assignments) {
-    return applyCategoryFilter(causeIds, CAUSE);
+    return applyCategoryFilter(assignments, ASSIGNMENT);
   }
 
   /**
-   * @param causeId cause id
+   * @param assignment assignment id
    * @return {@link SymptomsArray} containing filtered {@link Symptom}s
-   * @see #cause(Collection)
+   * @see #assignment(Collection)
    */
-  public SymptomsArray cause(String causeId) {
+  public SymptomsArray assignment(String assignment) {
-    return cause(Collections.singletonList(causeId));
+    return assignment(Collections.singletonList(assignment));
   }
 
   private SymptomsArray applyCategoryFilter(Collection<String> names, String column) {
@@ -258,7 +258,7 @@ public class SymptomsArray {
       result.add(new Symptom(id.get(i),
                              type.get(i),
                              Instant.ofEpochMilli(timeStamp.get(i)),
-                             Collections.singletonList(cause.get(i))));
+                             Collections.singletonList(assignment.get(i))));
     }
     return result;
   }

src/test/java/com/microsoft/dhalion/core/MeasurementsArrayTest.java

@@ -7,7 +7,6 @@
 
 package com.microsoft.dhalion.core;
 
-import com.microsoft.dhalion.core.Measurement.ScalarMeasurement;
 import com.microsoft.dhalion.core.MeasurementsArray.Builder;
 import com.microsoft.dhalion.core.MeasurementsArray.SortKey;
 import org.junit.Before;
@@ -38,9 +37,9 @@ public class MeasurementsArrayTest {
     for (String component : components) {
       for (String instance : instances) {
         for (String metric : metrics) {
-          measurements.add(new ScalarMeasurement(component, instance, metric, Instant.ofEpochMilli(value), value));
+          measurements.add(new Measurement(component, instance, metric, Instant.ofEpochMilli(value), value));
           value += 10;
-          measurements.add(new ScalarMeasurement(component, instance, metric, Instant.ofEpochMilli(value), value));
+          measurements.add(new Measurement(component, instance, metric, Instant.ofEpochMilli(value), value));
           value += 10;
         }
       }
@@ -170,27 +169,27 @@ public class MeasurementsArrayTest {
   public void slice() {
     assertEquals(24, testArray.size());
     Iterator<Measurement> measurements = testArray.get().iterator();
-    double firstValue = ((ScalarMeasurement) measurements.next()).value();
+    double firstValue = measurements.next().value();
-    double secondValue = ((ScalarMeasurement) measurements.next()).value();
+    double secondValue = measurements.next().value();
 
     resultArray = testArray.component("c1").slice(0, 1);
     assertEquals(2, resultArray.size());
     measurements = resultArray.get().iterator();
-    assertEquals(firstValue, ((ScalarMeasurement) measurements.next()).value(), 0.01);
+    assertEquals(firstValue, measurements.next().value(), 0.01);
-    assertEquals(secondValue, ((ScalarMeasurement) measurements.next()).value(), 0.01);
+    assertEquals(secondValue, measurements.next().value(), 0.01);
 
     resultArray = testArray.component("c3").slice(7, 7);
     assertEquals(1, resultArray.size());
     measurements = resultArray.get().iterator();
-    assertEquals(240, ((ScalarMeasurement) measurements.next()).value(), 0.01);
+    assertEquals(240, measurements.next().value(), 0.01);
   }
 
   @Test
   public void valueBetween() {
     resultArray = testArray.valueBetween(45, 65);
     assertEquals(2, resultArray.size());
-    resultArray.get().forEach(m -> assertTrue(45 <= ((ScalarMeasurement) m).value()));
+    resultArray.get().forEach(m -> assertTrue(45 <= m.value()));
-    resultArray.get().forEach(m -> assertTrue(65 >= ((ScalarMeasurement) m).value()));
+    resultArray.get().forEach(m -> assertTrue(65 >= m.value()));
   }
 
   @Test

src/test/java/com/microsoft/dhalion/core/SymptomsArrayTest.java

@@ -30,14 +30,14 @@ public class SymptomsArrayTest {
   public void createTestArray() {
     int[] ids = {1, 2, 3};
     String[] types = {"s1", "s2"};
-    List<String> causes = Arrays.asList("c1", "c2", "c3");
+    List<String> attributions = Arrays.asList("c1", "c2", "c3");
 
     Collection<Symptom> symptoms = new ArrayList<>();
 
     int value = 10;
     for (int id : ids) {
       for (String type : types) {
-        symptoms.add(new Symptom(id, type, Instant.ofEpochMilli(value), causes));
+        symptoms.add(new Symptom(id, type, Instant.ofEpochMilli(value), attributions));
         value += 10;
       }
     }
@@ -69,13 +69,13 @@ public class SymptomsArrayTest {
   }
 
   @Test
-  public void cause() {
+  public void assignment() {
-    resultArray = testArray.cause("c1");
+    resultArray = testArray.assignment("c1");
     assertEquals(6, resultArray.size());
-    resultArray.get().forEach(s -> assertEquals(1, s.causeIds().size()));
+    resultArray.get().forEach(s -> assertEquals(1, s.assignments().size()));
-    resultArray.get().forEach(s -> assertEquals("c1", s.causeIds().iterator().next()));
+    resultArray.get().forEach(s -> assertEquals("c1", s.assignments().iterator().next()));
 
-    resultArray = testArray.cause(Arrays.asList("c1", "c2"));
+    resultArray = testArray.assignment(Arrays.asList("c1", "c2"));
     assertEquals(12, resultArray.size());
   }
 
@@ -123,7 +123,7 @@ public class SymptomsArrayTest {
 
   @Test
   public void sort() {
-    resultArray = testArray.cause("c3").between(Instant.ofEpochMilli(20), Instant.ofEpochMilli(30));
+    resultArray = testArray.assignment("c3").between(Instant.ofEpochMilli(20), Instant.ofEpochMilli(30));
     assertEquals(2, resultArray.size());
     assertEquals("s2", resultArray.first().type());
     assertEquals("s1", resultArray.last().type());
@@ -150,20 +150,20 @@ public class SymptomsArrayTest {
     resultArray = testArray.id(1);
     assertEquals(6, resultArray.size());
     Iterator<Symptom> symptoms = testArray.get().iterator();
-    String firstCause = symptoms.next().causeIds().iterator().next();
+    String assignment1 = symptoms.next().assignments().iterator().next();
-    String secondCause = symptoms.next().causeIds().iterator().next();
+    String assignment2 = symptoms.next().assignments().iterator().next();
 
     resultArray = resultArray.slice(0, 1);
     assertEquals(2, resultArray.size());
     symptoms = resultArray.get().iterator();
-    assertEquals(firstCause, symptoms.next().causeIds().iterator().next());
+    assertEquals(assignment1, symptoms.next().assignments().iterator().next());
-    assertEquals(secondCause, symptoms.next().causeIds().iterator().next());
+    assertEquals(assignment2, symptoms.next().assignments().iterator().next());
   }
 
   @Test
   public void first() {
     Symptom symptom = testArray.first();
-    assertEquals("c1", symptom.causeIds().iterator().next());
+    assertEquals("c1", symptom.assignments().iterator().next());
     assertEquals(1, symptom.id());
     assertEquals(10, symptom.instant().toEpochMilli());
   }
@@ -171,7 +171,7 @@ public class SymptomsArrayTest {
   @Test
   public void last() {
     Symptom symptom = testArray.last();
-    assertEquals("c3", symptom.causeIds().iterator().next());
+    assertEquals("c3", symptom.assignments().iterator().next());
     assertEquals(3, symptom.id());
     assertEquals(60, symptom.instant().toEpochMilli());
   }