Updates to implement page skipping

Signed-off-by: Martin Lowe <martin.lowe@eclipse-foundation.org>

src/main/java/org/eclipsefoundation/marketplace/dto/codecs/ListingCodec.java

@@ -72,8 +72,6 @@ public class ListingCodec implements CollectibleCodec<Listing> {
 		doc.put(DatabaseFieldNames.LISTING_BODY, value.getTeaser());
 		doc.put(DatabaseFieldNames.LISTING_TEASER, value.getBody());
 		doc.put(DatabaseFieldNames.MARKETPLACE_FAVORITES, value.getFavoriteCount());
-		doc.put(DatabaseFieldNames.RECENT_INSTALLS, value.getInstallsRecent());
-		doc.put(DatabaseFieldNames.TOTAL_INSTALLS, value.getInstallsTotal());
 		doc.put(DatabaseFieldNames.LICENSE_TYPE, value.getLicense());
 		doc.put(DatabaseFieldNames.LISTING_STATUS, value.getStatus());
 		doc.put(DatabaseFieldNames.UPDATE_DATE, DateTimeHelper.toRFC3339(value.getUpdateDate()));
@@ -112,8 +110,8 @@ public class ListingCodec implements CollectibleCodec<Listing> {
 		out.setTeaser(document.getString(DatabaseFieldNames.LISTING_TEASER));
 		out.setBody(document.getString(DatabaseFieldNames.LISTING_BODY));
 		out.setStatus(document.getString(DatabaseFieldNames.LISTING_STATUS));
-		out.setInstallsRecent(document.getInteger(DatabaseFieldNames.RECENT_INSTALLS));
-		out.setInstallsTotal(document.getInteger(DatabaseFieldNames.TOTAL_INSTALLS));
+		out.setInstallsRecent(document.getInteger(DatabaseFieldNames.RECENT_INSTALLS,0));
+		out.setInstallsTotal(document.getInteger(DatabaseFieldNames.TOTAL_INSTALLS,0));
 		out.setLicense(document.getString(DatabaseFieldNames.LICENSE_TYPE));
 		out.setFavoriteCount(document.getLong(DatabaseFieldNames.MARKETPLACE_FAVORITES));
 		out.setFoundationMember(document.getBoolean(DatabaseFieldNames.FOUNDATION_MEMBER_FLAG));

src/main/java/org/eclipsefoundation/marketplace/dto/filter/ListingFilter.java

@@ -25,6 +25,7 @@ import com.mongodb.client.model.Aggregates;
 import com.mongodb.client.model.Field;
 import com.mongodb.client.model.Filters;
 import com.mongodb.client.model.Projections;
+import com.mongodb.client.model.UnwindOptions;
 
 /**
  * Filter implementation for the {@linkplain Listing} class.
@@ -95,7 +96,7 @@ public class ListingFilter implements DtoFilter<Listing> {
 		aggs.add(Aggregates.lookup(DtoTableNames.INSTALL_METRIC.getTableName(), DatabaseFieldNames.DOCID,
 				DatabaseFieldNames.DOCID, "installs"));
 		// unwinds the installs out of arrays
-		aggs.add(Aggregates.unwind("$installs"));
+		aggs.add(Aggregates.unwind("$installs", new UnwindOptions().preserveNullAndEmptyArrays(true)));
 		// push the installs counts to the listing, and remove the installs merged in
 		aggs.add(Aggregates.addFields(new Field<String>(DatabaseFieldNames.RECENT_INSTALLS, "$installs.offset_0.count"),
 				new Field<String>(DatabaseFieldNames.TOTAL_INSTALLS, "$installs.count")));

src/main/java/org/eclipsefoundation/marketplace/helper/DateTimeHelper.java

@@ -12,6 +12,7 @@ import java.time.format.DateTimeFormatter;
 import java.time.format.DateTimeParseException;
 import java.util.Date;
 
+import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -36,6 +37,7 @@ public class DateTimeHelper {
 	 *         3339 format.
 	 */
 	public static Date toRFC3339(String dateString) {
+		if (StringUtils.isBlank(dateString)) return null;
 		try {
 			return Date.from(ZonedDateTime.parse(dateString, formatter).toInstant());
 		} catch (DateTimeParseException e) {
@@ -52,6 +54,7 @@ public class DateTimeHelper {
 	 * @return the RFC 3339 format date string.
 	 */
 	public static String toRFC3339(Date date) {
+		if (date == null) return null;
 		return formatter.format(date.toInstant().atZone(ZoneId.of("UTC")));
 	}
 

src/main/java/org/eclipsefoundation/marketplace/model/MongoQuery.java

@@ -106,14 +106,25 @@ public class MongoQuery<T> {
 			out.add(Aggregates.match(filter));
 		}
 		// add base aggregates (joins)
-		out.addAll(aggregates);
+		out.addAll(aggregates); 
+		if (sort != null) {
+			out.add(Aggregates.sort(sort));
+		}
+		// check if the page param has been set, defaulting to the first page if not set
+		Optional<String> pageOpt = wrapper.getFirstParam(UrlParameterNames.PAGE);
+		int page = 1;
+		if (pageOpt.isPresent() && StringUtils.isNumeric(pageOpt.get())) {
+			int tmpPage = Integer.parseInt(pageOpt.get());
+			if (tmpPage > 0) {
+				page = tmpPage;
+				LOGGER.debug("Found a set page of {} for current query",page);
+			}
+		}
+		out.add(Aggregates.skip((page - 1) * limit));
 		// add sample if we aren't sorting
 		if ((sort == null || SortOrder.RANDOM.equals(order)) && dtoFilter.useLimit()) {
 			out.add(Aggregates.sample(limit));
 		}
-		if (sort != null) {
-			out.add(Aggregates.sort(sort));
-		}
 		return out;
 	}
 
@@ -133,8 +144,6 @@ public class MongoQuery<T> {
 	}
 
 	private void setSort(String sortField, String sortOrder, List<Bson> filters) {
-		Optional<String> lastOpt = wrapper.getFirstParam(UrlParameterNames.LAST_SEEN);
-
 		List<Sortable<?>> fields = SortableHelper.getSortableFields(getDocType());
 		Optional<Sortable<?>> fieldContainer = SortableHelper.getSortableFieldByName(fields, sortField);
 		if (fieldContainer.isPresent()) {
@@ -142,17 +151,9 @@ public class MongoQuery<T> {
 			// add sorting query if the sortOrder matches a defined order
 			switch (order) {
 			case ASCENDING:
-				// if last seen is set, add a filter to shift the results
-				if (lastOpt.isPresent()) {
-					filters.add(Filters.gte(sortField, fieldContainer.get().castValue(lastOpt.get())));
-				}
 				this.sort = Filters.eq(sortField, order.getOrder());
 				break;
 			case DESCENDING:
-				// if last seen is set, add a filter to shift the results
-				if (lastOpt.isPresent()) {
-					filters.add(Filters.lte(sortField, fieldContainer.get().castValue(lastOpt.get())));
-				}
 				this.sort = Filters.eq(sortField, order.getOrder());
 				break;
 			default:

src/main/java/org/eclipsefoundation/marketplace/namespace/UrlParameterNames.java

@@ -17,7 +17,7 @@ package org.eclipsefoundation.marketplace.namespace;
 public final class UrlParameterNames {
 
 	public static final String QUERY_STRING = "q";
-	public static final String LAST_SEEN = "last";
+	public static final String PAGE = "page";
 	public static final String LIMIT = "limit";
 	public static final String SORT = "sort";
 	public static final String OS = "os";