add lastContributionTimestamp to OSMEntitySnapshot objects

GIScience · Mar 23, 2023 · ec1ec18 · ec1ec18
1 parent f4ef6eb
commit ec1ec18
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Showing 5 changed files with 55 additions and 3 deletions.
diff --git a/oshdb-api/src/main/java/org/heigit/ohsome/oshdb/api/object/OSMEntitySnapshotImpl.java b/oshdb-api/src/main/java/org/heigit/ohsome/oshdb/api/object/OSMEntitySnapshotImpl.java
@@ -38,6 +38,7 @@ public OSMEntitySnapshotImpl(
   ) {
     this.data = new IterateByTimestampEntry(
         other.getTimestamp(),
+        other.getLastContributionTimestamp(),
         other.getEntity(),
         other.getOSHEntity(),
         reclippedGeometry,
@@ -50,6 +51,11 @@ public OSHDBTimestamp getTimestamp() {
     return data.timestamp();
   }
 
+  @Override
+  public OSHDBTimestamp getLastContributionTimestamp() {
+    return data.lastModificationTimestamp();
+  }
+
   @Override
   public Geometry getGeometry() {
     return data.geometry().get();

diff --git a/oshdb-api/src/test/java/org/heigit/ohsome/oshdb/api/tests/TestAutoAggregation.java b/oshdb-api/src/test/java/org/heigit/ohsome/oshdb/api/tests/TestAutoAggregation.java
@@ -194,7 +194,8 @@ protected <R, S> S flatMapReduceCellsOSMEntitySnapshotGroupedById(
 
   private static OSMEntitySnapshot snapshot(OSHNode node) {
     var timestamp = timestamps.get().first();
-    var data = new IterateByTimestampEntry(timestamp, node.getVersions().iterator().next(), node,
+    var data = new IterateByTimestampEntry(timestamp, null,
+        node.getVersions().iterator().next(), node,
         new LazyEvaluatedObject<>(point),
         new LazyEvaluatedObject<>(point));
     return new OSMEntitySnapshotImpl(data);

diff --git a/oshdb-util/src/main/java/org/heigit/ohsome/oshdb/util/celliterator/CellIterator.java b/oshdb-util/src/main/java/org/heigit/ohsome/oshdb/util/celliterator/CellIterator.java
@@ -211,6 +211,7 @@ public CellIterator(
    * Holds the result of a single item returned by {@link #iterateByTimestamps(GridOSHEntity)}.
    *
    * @param timestamp timestamp of the snapshot
+   * @param lastModificationTimestamp last modification timestamp before the snapshot's timestamp
    * @param osmEntity the exact version of the OSM object
    * @param oshEntity the whole version history of the OSM object
    * @param geometry an object which holds the geometry of the OSM object, or a method to build it
@@ -220,6 +221,7 @@ public CellIterator(
    */
   public record IterateByTimestampEntry(
       OSHDBTimestamp timestamp,
+      OSHDBTimestamp lastModificationTimestamp,
       @Nonnull OSMEntity osmEntity,
       @Nonnull OSHEntity oshEntity,
       LazyEvaluatedObject<Geometry> geometry,
@@ -281,22 +283,26 @@ public Stream<IterateByTimestampEntry> iterateByTimestamps(Stream<? extends OSHE
       // optimize loop by requesting modification timestamps first, and skip geometry calculations
       // where not needed
       SortedMap<OSHDBTimestamp, List<OSHDBTimestamp>> queryTs = new TreeMap<>();
+      SortedMap<OSHDBTimestamp, OSHDBTimestamp> lastModificationTimestamps = new TreeMap<>();
       if (!includeOldStyleMultipolygons) {
         List<OSHDBTimestamp> modTs =
             OSHEntityTimeUtils.getModificationTimestamps(oshEntity, osmEntityFilter);
         int j = 0;
+        OSHDBTimestamp lastModificationTimestamp = null;
         for (OSHDBTimestamp requestedT : timestamps) {
           boolean needToRequest = false;
           while (j < modTs.size()
               && modTs.get(j).getEpochSecond() <= requestedT.getEpochSecond()) {
             needToRequest = true;
+            lastModificationTimestamp = modTs.get(j);
             j++;
           }
           if (needToRequest) {
             queryTs.put(requestedT, new LinkedList<>());
           } else if (queryTs.size() > 0) {
             queryTs.get(queryTs.lastKey()).add(requestedT);
           }
+          lastModificationTimestamps.put(requestedT, lastModificationTimestamp);
         }
       } else {
         // todo: make this work with old style multipolygons!!?!
@@ -381,16 +387,17 @@ public Stream<IterateByTimestampEntry> iterateByTimestamps(Stream<? extends OSHE
             });
           }
 
+          var lastModificationTimestamp = lastModificationTimestamps.get(timestamp);
           if (fullyInside || !geom.get().isEmpty()) {
             LazyEvaluatedObject<Geometry> fullGeom = fullyInside ? geom : new LazyEvaluatedObject<>(
                 () -> OSHDBGeometryBuilder.getGeometry(osmEntity, timestamp, tagInterpreter));
             results.add(new IterateByTimestampEntry(
-                timestamp, osmEntity, oshEntity, geom, fullGeom)
+                timestamp, lastModificationTimestamp, osmEntity, oshEntity, geom, fullGeom)
             );
             // add skipped timestamps (where nothing has changed from the last timestamp) to result
             for (OSHDBTimestamp additionalT : queryTs.get(timestamp)) {
               results.add(new IterateByTimestampEntry(
-                  additionalT, osmEntity, oshEntity, geom, fullGeom)
+                  additionalT, lastModificationTimestamp, osmEntity, oshEntity, geom, fullGeom)
               );
             }
           }

diff --git a/oshdb-util/src/main/java/org/heigit/ohsome/oshdb/util/mappable/OSMEntitySnapshot.java b/oshdb-util/src/main/java/org/heigit/ohsome/oshdb/util/mappable/OSMEntitySnapshot.java
@@ -16,6 +16,13 @@ public interface OSMEntitySnapshot extends OSHDBMapReducible, Comparable<OSMEnti
    */
   OSHDBTimestamp getTimestamp();
 
+  /**
+   * The timestamp when the entity of the snapshot was last modified before the snapshot timestamp.
+   *
+   * @return last modification timestamp as an OSHDBTimestamp object
+   */
+  OSHDBTimestamp getLastContributionTimestamp();
+
   /**
    * The geometry of this entity at the snapshot's timestamp clipped to the requested area of
    * interest.

diff --git a/...src/test/java/org/heigit/ohsome/oshdb/util/celliterator/IterateByTimestampsNodesTest.java b/...src/test/java/org/heigit/ohsome/oshdb/util/celliterator/IterateByTimestampsNodesTest.java
@@ -271,4 +271,35 @@ void testCoordinatesRelativeToPolygon() throws IOException {
     assertEquals(13, result.get(1).osmEntity().getId());
     assertEquals(14, result.get(2).osmEntity().getId());
   }
+
+  @Test
+  void testLastContributionTimestamp() {
+    // node 3: creation and 4 visible changes, but no geometry and no tag changes
+
+    List<IterateByTimestampEntry> result = (new CellIterator(
+        new OSHDBTimestamps(
+            "2000-06-01T00:00:00Z",
+            "2018-06-01T00:00:00Z",
+            "P1Y"
+        ).get(),
+        OSHDBBoundingBox.bboxWgs84Coordinates(-180.0, -90.0, 180.0, 90.0),
+        areaDecider,
+        oshEntity -> oshEntity.getId() == 3,
+        osmEntity -> true,
+        false
+    )).iterateByTimestamps(
+        oshdbDataGridCell
+    ).toList();
+    assertEquals(5, result.size());
+    assertEquals("2007-06-01T00:00:00", result.get(0).timestamp().toString());
+    assertEquals("2007-01-01T00:00:00", result.get(0).lastModificationTimestamp().toString());
+    assertEquals("2014-06-01T00:00:00", result.get(1).timestamp().toString());
+    assertEquals("2014-01-01T00:00:00", result.get(1).lastModificationTimestamp().toString());
+    assertEquals("2016-06-01T00:00:00", result.get(2).timestamp().toString());
+    assertEquals("2016-01-01T00:00:00", result.get(2).lastModificationTimestamp().toString());
+    assertEquals("2017-06-01T00:00:00", result.get(3).timestamp().toString());
+    assertEquals("2016-01-01T00:00:00", result.get(3).lastModificationTimestamp().toString());
+    assertEquals("2018-06-01T00:00:00", result.get(4).timestamp().toString());
+    assertEquals("2016-01-01T00:00:00", result.get(4).lastModificationTimestamp().toString());
+  }
 }