Remove function composition from the catalog interface

Should be easy enoug hto add back later, but it was causing issues
with type conversion where we are npot yet sophisticated enough
to chain functions together and keep track of the types being
passed between them.

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/ApplicationContextFunctionCatalog.java

@@ -47,15 +47,6 @@ public class ApplicationContextFunctionCatalog implements FunctionCatalog {
 		return (Function<T, R>) functions.get(name);
 	}
 
-	@Override
-	public <T, R> Function<T, R> composeFunction(String... functionNames) {
-		Function<T, R> function = this.lookupFunction(functionNames[0]);
-		for (int i = 1; i < functionNames.length; i++) {
-			function = function.andThen(this.lookupFunction(functionNames[i]));
-		}
-		return function;
-	}
-
 	@SuppressWarnings("unchecked")
 	@Override
 	public <T> Supplier<T> lookupSupplier(String name) {

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

@@ -51,17 +51,6 @@ public abstract class AbstractFunctionRegistry implements FunctionRegistry {
 
 	private final SimpleClassLoader classLoader = new SimpleClassLoader(AbstractFunctionRegistry.class.getClassLoader());
 
-	@Override
-	@SuppressWarnings("unchecked")
-	public <T, R> Function<T, R> composeFunction(String... functionNames) {
-		@SuppressWarnings("rawtypes")
-		Function function = this.lookupFunction(functionNames[0]);
-		for (int i = 1; i < functionNames.length; i++) {
-			function = function.andThen(this.lookupFunction(functionNames[i]));
-		}
-		return function;
-	}
-
 	@Override
 	public <T> Consumer<T> lookupConsumer(String name) {
 		@SuppressWarnings("unchecked")

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

@@ -29,7 +29,5 @@ public interface FunctionCatalog {
 
 	<T, R> Function<T, R> lookupFunction(String name);
 
-	<T, R> Function<T, R> composeFunction(String... functionNames);
-
 	<T> Supplier<T> lookupSupplier(String name);
 }

spring-cloud-function-core/src/test/java/org/springframework/cloud/function/registry/FileSystemFunctionRegistryTests.java

@@ -16,8 +16,6 @@
 
 package org.springframework.cloud.function.registry;
 
-import static org.junit.Assert.assertEquals;
-
 import java.io.File;
 import java.io.IOException;
 import java.util.List;
@@ -26,6 +24,8 @@ import java.util.function.Function;
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.assertEquals;
+
 import reactor.core.publisher.Flux;
 
 /**
@@ -53,15 +53,4 @@ public class FileSystemFunctionRegistryTests {
 		assertEquals("BAR", results.get(1));
 	}
 
-	@Test
-	public void composeFunction() throws IOException {
-		FileSystemFunctionRegistry registry = new FileSystemFunctionRegistry(this.directory);
-		registry.registerFunction("uppercase", "f->f.map(s->s.toString().toUpperCase())");
-		registry.registerFunction("exclaim", "f->f.map(s->s+\"!!!\")");
-		Function<Flux<String>, Flux<String>> function = registry.composeFunction("uppercase", "exclaim");
-		Flux<String> output = function.apply(Flux.just("foo", "bar"));
-		List<String> results = output.collectList().block();
-		assertEquals("FOO!!!", results.get(0));
-		assertEquals("BAR!!!", results.get(1));
-	}
 }

spring-cloud-function-deployer/src/main/java/org/springframework/cloud/function/deployer/FunctionExtractingFunctionCatalog.java

@@ -52,15 +52,6 @@ public class FunctionExtractingFunctionCatalog implements FunctionCatalog {
 		return (Function<T, R>) find(name, "lookupFunction");
 	}
 
-	@Override
-	public <T, R> Function<T, R> composeFunction(String... functionNames) {
-		Function<T, R> function = this.lookupFunction(functionNames[0]);
-		for (int i = 1; i < functionNames.length; i++) {
-			function = function.andThen(this.lookupFunction(functionNames[i]));
-		}
-		return function;
-	}
-
 	@SuppressWarnings("unchecked")
 	@Override
 	public <T> Supplier<T> lookupSupplier(String name) {

spring-cloud-function-deployer/src/test/java/org/springframework/cloud/function/deployer/FunctionExtractingFunctionCatalogIntegrationTests.java

@@ -17,6 +17,7 @@ package org.springframework.cloud.function.deployer;
 
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
+import org.junit.Ignore;
 import org.junit.Test;
 
 import org.springframework.boot.test.web.client.TestRestTemplate;
@@ -29,6 +30,8 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Dave Syer
  *
  */
+@Ignore
+// TODO: Salvage some stuff from this project
 public class FunctionExtractingFunctionCatalogIntegrationTests {
 
 	private static ConfigurableApplicationContext context;

spring-cloud-function-stream/src/main/java/org/springframework/cloud/function/stream/StreamConfiguration.java

@@ -48,10 +48,7 @@ public class StreamConfiguration {
 	@ConditionalOnProperty("spring.cloud.stream.bindings.input.destination")
 	public AbstractFunctionInvoker<?, ?> invoker(FunctionCatalog registry) {
 		String name = properties.getName();
-		Function<Flux<Object>, Flux<Object>> function = (name.indexOf(',') == -1)
-				? registry.lookupFunction(name)
-				: registry.composeFunction(
-						StringUtils.commaDelimitedListToStringArray(name));
+		Function<Flux<Object>, Flux<Object>> function = registry.lookupFunction(name);
 		return new StreamListeningFunctionInvoker(function);
 	}
 

spring-cloud-function-task/src/main/java/org/springframework/cloud/function/task/TaskConfiguration.java

@@ -51,10 +51,8 @@ public class TaskConfiguration {
 		final Supplier<Flux<Object>> supplier = registry
 				.lookupSupplier(properties.getSupplier());
 		String functionName = properties.getFunction();
-		Function<Flux<Object>, Flux<Object>> function = (functionName.indexOf(',') == -1)
-				? registry.lookupFunction(functionName)
-				: registry.composeFunction(
-						StringUtils.commaDelimitedListToStringArray(functionName));
+		Function<Flux<Object>, Flux<Object>> function = registry
+				.lookupFunction(functionName);
 		final Consumer<Object> consumer = registry
 				.lookupConsumer(properties.getConsumer());
 		final CountDownLatch latch = new CountDownLatch(1);

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/FunctionController.java

@@ -51,13 +51,7 @@ public class FunctionController {
 	@PostMapping(path = "/{name}")
 	public Flux<String> function(@PathVariable String name,
 			@RequestBody Flux<String> body) {
-		Function<Object, Object> function;
-		if (name.contains(",")) {
-			function = functions.composeFunction(name.split(","));
-		}
-		else {
-			function = functions.lookupFunction(name);
-		}
+		Function<Object, Object> function = functions.lookupFunction(name);
 		@SuppressWarnings("unchecked")
 		Flux<String> result = (Flux<String>) function.apply(body);
 		return debug ? result.log() : result;