GH-56 Added support for Function<Flux, Mono> and <Mono, Flux>

Resolves #56
Resolves #218

spring-cloud-function-core/src/main/java/org/springframework/cloud/function/core/FluxToMonoFunction.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.core;
+
+import java.util.function.Function;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+/**
+ * Marker wrapper for target Function<Flux, Mono>
+ *
+ * @author Oleg Zhurakousky
+ * @since 2.0
+ *
+ * @param <T> type of {@link Flux} input of the target function
+ * @param <R> type of {@link Mono} output of the target function
+ */
+public class FluxToMonoFunction<I,O> implements Function<Flux<I>, Mono<O>>, FluxWrapper<Function<Flux<I>, Mono<O>>> {
+
+	private final Function<Flux<I>, Mono<O>> function;
+
+	/**
+	 * @param function target function
+	 */
+	public FluxToMonoFunction(Function<Flux<I>, Mono<O>> function) {
+		this.function = function;
+	}
+
+	@Override
+	public Function<Flux<I>, Mono<O>> getTarget() {
+		return function;
+	}
+
+	@Override
+	public Mono<O> apply(Flux<I> input) {
+		return function.apply(input);
+	}
+}

spring-cloud-function-core/src/main/java/org/springframework/cloud/function/core/MonoToFluxFunction.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.core;
+
+import java.util.function.Function;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+/**
+ * Marker wrapper for target Function<Mono, Flux>
+ *
+ * @author Oleg Zhurakousky
+ * @since 2.0
+ *
+ * @param <T> type of {@link Mono} input of the target function
+ * @param <R> type of {@link Flux} output of the target function
+ */
+public class MonoToFluxFunction<I,O> implements Function<Mono<I>, Flux<O>>, FluxWrapper<Function<Mono<I>, Flux<O>>> {
+
+	private final Function<Mono<I>, Flux<O>> function;
+
+	/**
+	 * @param function target function
+	 * @param names name(s) of the target function (optional)
+	 */
+	public MonoToFluxFunction(Function<Mono<I>, Flux<O>> function) {
+		this.function = function;
+	}
+
+	@Override
+	public Function<Mono<I>, Flux<O>> getTarget() {
+		return function;
+	}
+
+	@Override
+	public Flux<O> apply(Mono<I> input) {
+		return function.apply(input);
+	}
+}