DATAMONGO-1719 - Polishing.

Use empty query where possible to avoid null values and introduce non optional findAndModify alternative for imperative api.
Add missing ExecutableUpdateOperation Kotlin extension.
Update Javadoc and add non-Javadoc comments.

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableInsertOperation.java

@@ -94,12 +94,6 @@ interface TerminatingBulkInsert<T> {
 		BulkWriteResult bulk(Collection<? extends T> objects);
 	}
 
-	/**
-	 * @author Christoph Strobl
-	 * @since 2.0
-	 */
-	interface ExecutableInsert<T> extends TerminatingInsert<T>, InsertWithCollection<T>, InsertWithBulkMode<T> {}
-
 	/**
 	 * Collection override (optional).
 	 *
@@ -134,4 +128,10 @@ interface InsertWithBulkMode<T> extends TerminatingInsert<T> {
 		 */
 		TerminatingBulkInsert<T> withBulkMode(BulkMode bulkMode);
 	}
+
+	/**
+	 * @author Christoph Strobl
+	 * @since 2.0
+	 */
+	interface ExecutableInsert<T> extends TerminatingInsert<T>, InsertWithCollection<T>, InsertWithBulkMode<T> {}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableRemoveOperationSupport.java

@@ -22,8 +22,6 @@
 
 import java.util.List;
 
-import org.bson.Document;
-import org.springframework.data.mongodb.core.query.BasicQuery;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -39,6 +37,8 @@
  */
 class ExecutableRemoveOperationSupport implements ExecutableRemoveOperation {
 
+	private static final Query ALL_QUERY = new Query();
+
 	private final MongoTemplate tempate;
 
 	/**
@@ -59,7 +59,7 @@ public <T> ExecutableRemove<T> remove(Class<T> domainType) {
 
 		Assert.notNull(domainType, "DomainType must not be null!");
 
-		return new ExecutableRemoveSupport<>(tempate, domainType, null, null);
+		return new ExecutableRemoveSupport<>(tempate, domainType, ALL_QUERY, null);
 	}
 
 	/**
@@ -96,23 +96,19 @@ public DeleteResult all() {
 
 			String collectionName = getCollectionName();
 
-			return template.doRemove(collectionName, getQuery(), domainType);
+			return template.doRemove(collectionName, query, domainType);
 		}
 
 		@Override
 		public List<T> findAndRemove() {
 
 			String collectionName = getCollectionName();
 
-			return template.doFindAndDelete(collectionName, getQuery(), domainType);
+			return template.doFindAndDelete(collectionName, query, domainType);
 		}
 
 		private String getCollectionName() {
 			return StringUtils.hasText(collection) ? collection : template.determineCollectionName(domainType);
 		}
-
-		private Query getQuery() {
-			return query != null ? query : new BasicQuery(new Document());
-		}
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableUpdateOperation.java

@@ -56,12 +56,6 @@ public interface ExecutableUpdateOperation {
 	 */
 	<T> ExecutableUpdate<T> update(Class<T> domainType);
 
-	/**
-	 * @author Christoph Strobl
-	 * @since 2.0
-	 */
-	interface ExecutableUpdate<T> extends UpdateWithCollection<T>, UpdateWithQuery<T>, UpdateWithUpdate<T> {}
-
 	/**
 	 * Declare the {@link Update} to apply.
 	 *
@@ -145,7 +139,16 @@ interface TerminatingFindAndModify<T> {
 		 *
 		 * @return {@link Optional#empty()} if nothing found.
 		 */
-		Optional<T> findAndModify();
+		default Optional<T> findAndModify() {
+			return Optional.ofNullable(findAndModifyValue());
+		}
+
+		/**
+		 * Find, modify and return the first matching document.
+		 *
+		 * @return {@literal null} if nothing found.
+		 */
+		T findAndModifyValue();
 	}
 
 	/**
@@ -177,4 +180,10 @@ interface TerminatingUpdate<T> extends TerminatingFindAndModify<T>, FindAndModif
 		 */
 		UpdateResult upsert();
 	}
+
+	/**
+	 * @author Christoph Strobl
+	 * @since 2.0
+	 */
+	interface ExecutableUpdate<T> extends UpdateWithCollection<T>, UpdateWithQuery<T>, UpdateWithUpdate<T> {}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableUpdateOperationSupport.java

@@ -22,8 +22,6 @@
 
 import java.util.Optional;
 
-import org.bson.Document;
-import org.springframework.data.mongodb.core.query.BasicQuery;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.Update;
 import org.springframework.util.Assert;
@@ -40,6 +38,8 @@
  */
 class ExecutableUpdateOperationSupport implements ExecutableUpdateOperation {
 
+	private static final Query ALL_QUERY = new Query();
+
 	private final MongoTemplate template;
 
 	/**
@@ -59,7 +59,7 @@ public <T> ExecutableUpdate<T> update(Class<T> domainType) {
 
 		Assert.notNull(domainType, "DomainType must not be null!");
 
-		return new ExecutableUpdateSupport<>(template, domainType, null, null, null, null);
+		return new ExecutableUpdateSupport<>(template, domainType, ALL_QUERY, null, null, null);
 	}
 
 	/**
@@ -105,12 +105,8 @@ public UpdateResult upsert() {
 		}
 
 		@Override
-		public Optional<T> findAndModify() {
-
-			String collectionName = getCollectionName();
-
-			return Optional.ofNullable(template.findAndModify(query != null ? query : new BasicQuery(new Document()), update,
-					options, domainType, collectionName));
+		public T findAndModifyValue() {
+			return template.findAndModify(query, update, options, domainType, getCollectionName());
 		}
 
 		@Override
@@ -135,12 +131,7 @@ public TerminatingFindAndModify<T> withOptions(FindAndModifyOptions options) {
 		}
 
 		private UpdateResult doUpdate(boolean multi, boolean upsert) {
-
-			String collectionName = getCollectionName();
-
-			Query query = this.query != null ? this.query : new BasicQuery(new Document());
-
-			return template.doUpdate(collectionName, query, update, domainType, upsert, multi);
+			return template.doUpdate(getCollectionName(), query, update, domainType, upsert, multi);
 		}
 
 		private String getCollectionName() {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveAggregationOperation.java

@@ -36,6 +36,7 @@
  * </pre>
  *
  * @author Mark Paluch
+ * @author Christoph Strobl
  * @since 2.0
  */
 public interface ReactiveAggregationOperation {
@@ -46,7 +47,7 @@ public interface ReactiveAggregationOperation {
 	 * input type for he aggregation.
 	 *
 	 * @param domainType must not be {@literal null}.
-	 * @return new instance of {@link ReactiveAggregation}.
+	 * @return new instance of {@link ReactiveAggregation}. Never {@literal null}.
 	 * @throws IllegalArgumentException if domainType is {@literal null}.
 	 */
 	<T> ReactiveAggregation<T> aggregateAndReturn(Class<T> domainType);
@@ -61,8 +62,8 @@ interface AggregationOperationWithCollection<T> {
 		 * Skip this step to use the default collection derived from the domain type.
 		 *
 		 * @param collection must not be {@literal null} nor {@literal empty}.
-		 * @return new instance of {@link AggregationOperationWithAggregation}.
-		 * @throws IllegalArgumentException if collection is {@literal null}.
+		 * @return new instance of {@link AggregationOperationWithAggregation}. Never {@literal null}.
+		 * @throws IllegalArgumentException if collection is {@literal null} or empty.
 		 */
 		AggregationOperationWithAggregation<T> inCollection(String collection);
 	}
@@ -89,7 +90,7 @@ interface AggregationOperationWithAggregation<T> {
 		 * Set the aggregation to be used.
 		 *
 		 * @param aggregation must not be {@literal null}.
-		 * @return new instance of {@link TerminatingAggregationOperation}.
+		 * @return new instance of {@link TerminatingAggregationOperation}. Never {@literal null}.
 		 * @throws IllegalArgumentException if aggregation is {@literal null}.
 		 */
 		TerminatingAggregationOperation<T> by(Aggregation aggregation);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveAggregationOperationSupport.java

@@ -27,9 +27,10 @@
 import org.springframework.util.StringUtils;
 
 /**
- * Implementation of {@link ExecutableAggregationOperation} operating directly on {@link ReactiveMongoTemplate}.
+ * Implementation of {@link ReactiveAggregationOperation} operating directly on {@link ReactiveMongoTemplate}.
  *
  * @author Mark Paluch
+ * @autor Christoph Strobl
  * @since 2.0
  */
 class ReactiveAggregationOperationSupport implements ReactiveAggregationOperation {
@@ -49,6 +50,10 @@ class ReactiveAggregationOperationSupport implements ReactiveAggregationOperatio
 		this.template = template;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation#aggregateAndReturn(java.lang.Class)
+	 */
 	@Override
 	public <T> ReactiveAggregation<T> aggregateAndReturn(Class<T> domainType) {
 
@@ -67,6 +72,10 @@ static class ReactiveAggregationSupport<T>
 		Aggregation aggregation;
 		String collection;
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation.AggregationOperationWithCollection#inCollection(java.lang.String)
+		 */
 		@Override
 		public AggregationOperationWithAggregation<T> inCollection(String collection) {
 
@@ -75,6 +84,10 @@ public AggregationOperationWithAggregation<T> inCollection(String collection) {
 			return new ReactiveAggregationSupport<>(template, domainType, aggregation, collection);
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation.AggregationOperationWithAggregation#by(org.springframework.data.mongodb.core.Aggregation)
+		 */
 		@Override
 		public TerminatingAggregationOperation<T> by(Aggregation aggregation) {
 
@@ -83,6 +96,10 @@ public TerminatingAggregationOperation<T> by(Aggregation aggregation) {
 			return new ReactiveAggregationSupport<>(template, domainType, aggregation, collection);
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.ReactiveAggregationOperation.TerminatingAggregationOperation#all()
+		 */
 		@Override
 		public Flux<T> all() {
 			return template.aggregate(aggregation, getCollectionName(aggregation), domainType);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFindOperation.java

@@ -44,6 +44,7 @@
  * </pre>
  *
  * @author Mark Paluch
+ * @author Christoph Strobl
  * @since 2.0
  */
 public interface ReactiveFindOperation {
@@ -52,7 +53,7 @@ public interface ReactiveFindOperation {
 	 * Start creating a find operation for the given {@literal domainType}.
 	 *
 	 * @param domainType must not be {@literal null}.
-	 * @return new instance of {@link ReactiveFind}.
+	 * @return new instance of {@link ReactiveFind}. Never {@literal null}.
 	 * @throws IllegalArgumentException if domainType is {@literal null}.
 	 */
 	<T> ReactiveFind<T> query(Class<T> domainType);
@@ -65,15 +66,15 @@ interface TerminatingFind<T> {
 		/**
 		 * Get exactly zero or one result.
 		 *
-		 * @return {@link Mono#empty()} if no match found.
+		 * @return {@link Mono#empty()} if no match found. Never {@literal null}.
 		 * @throws org.springframework.dao.IncorrectResultSizeDataAccessException if more than one match found.
 		 */
 		Mono<T> one();
 
 		/**
 		 * Get the first or no result.
 		 *
-		 * @return {@link Mono#empty()} if no match found.
+		 * @return {@link Mono#empty()} if no match found. Never {@literal null}.
 		 */
 		Mono<T> first();
 
@@ -87,14 +88,14 @@ interface TerminatingFind<T> {
 		/**
 		 * Get the number of matching elements.
 		 *
-		 * @return total number of matching elements.
+		 * @return {@link Mono} emitting total number of matching elements. Never {@literal null}.
 		 */
 		Mono<Long> count();
 
 		/**
 		 * Check for the presence of matching elements.
 		 *
-		 * @return {@literal true} if at least one matching element exists.
+		 * @return {@link Mono} emitting {@literal true} if at least one matching element exists. Never {@literal null}.
 		 */
 		Mono<Boolean> exists();
 	}