GH-202 Added size() to FunctionCatalog

Resolves #202

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

@@ -47,4 +47,12 @@ public interface FunctionCatalog {
 
 	Set<String> getNames(Class<?> type);
 
+	/**
+	 * Return the count of functions registered in this catalog
+	 * @return the count of functions registered in this catalog
+	 */
+	default int size() {
+		throw new UnsupportedOperationException("This instance of FunctionCatalog does not support this operation");
+	}
+
 }

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

@@ -169,6 +169,13 @@ public class ContextFunctionCatalogAutoConfiguration {
             return Collections.emptySet();
         }
 
+        @Override
+        public int size() {
+            return this.processor.getSuppliers().size() +
+                    this.processor.getFunctions().size() +
+                    this.processor.getConsumers().size();
+        }
+
         public BeanFactoryFunctionCatalog(ContextFunctionRegistry processor) {
             this.processor = processor;
         }