[DatePicker] Make new public getter methods for start/end/openAt valu…

…es with long return types for CalendarConstraints

Resolves #2907

PiperOrigin-RevId: 473053039

lib/java/com/google/android/material/datepicker/CalendarConstraints.java

@@ -96,13 +96,13 @@ public DateValidator getDateValidator() {
 
   /** Returns the earliest month allowed by this set of bounds. */
   @NonNull
-  public Month getStart() {
+  Month getStart() {
     return start;
   }
 
   /** Returns the latest month allowed by this set of bounds. */
   @NonNull
-  public Month getEnd() {
+  Month getEnd() {
     return end;
   }
 
@@ -138,6 +138,25 @@ int getYearSpan() {
     return yearSpan;
   }
 
+  /** Returns the earliest time in milliseconds allowed by this set of bounds. */
+  public long getStartMs() {
+    return start.timeInMillis;
+  }
+
+  /** Returns the latest time in milliseconds allowed by this set of bounds. */
+  public long getEndMs() {
+    return end.timeInMillis;
+  }
+
+  /**
+   * Returns the openAt time in milliseconds within this set of bounds. Returns null if not
+   * available.
+   */
+  @Nullable
+  public Long getOpenAtMs() {
+    return openAt == null ? null : openAt.timeInMillis;
+  }
+
   @Override
   public boolean equals(Object o) {
     if (this == o) {

lib/javatests/com/google/android/material/datepicker/CalendarConstraintsTest.java

@@ -175,4 +175,28 @@ public void setEnd_succeeds() {
 
     assertThat(calendarConstraints.getEnd().timeInMillis).isEqualTo(FEB_2016);
   }
+
+  @Test
+  public void getStartMs_succeeds() {
+    CalendarConstraints calendarConstraints =
+        new CalendarConstraints.Builder().setStart(FEB_2016).build();
+
+    assertThat(calendarConstraints.getStartMs()).isEqualTo(FEB_2016);
+  }
+
+  @Test
+  public void getEndMs_succeeds() {
+    CalendarConstraints calendarConstraints =
+        new CalendarConstraints.Builder().setEnd(FEB_2016).build();
+
+    assertThat(calendarConstraints.getEndMs()).isEqualTo(FEB_2016);
+  }
+
+  @Test
+  public void getOpenAtMs_succeeds() {
+    CalendarConstraints calendarConstraints =
+        new CalendarConstraints.Builder().setOpenAt(FEB_2016).build();
+
+    assertThat(calendarConstraints.getOpenAtMs()).isEqualTo(FEB_2016);
+  }
 }