middleware support for java worker

src/main/java/com/microsoft/azure/functions/ExecutionContext.java

@@ -6,6 +6,8 @@
 
 package com.microsoft.azure.functions;
 
+import java.lang.reflect.Parameter;
+import java.util.Map;
 import java.util.logging.Logger;
 
 /**
@@ -50,5 +52,15 @@ default TraceContext getTraceContext() {
     default RetryContext getRetryContext() {
         return null;
     }
+
+    Object getReturnValue();
+
+    Map<String, Parameter> getParamInfoMap();
+
+    void setInputArgument(String key, Object value);
+
+    Map<String, String> getArgumentPayloadMap();
+
+    void setMiddlewareOutput(Object value);
 }
 

src/main/java/com/microsoft/azure/functions/middleware/FunctionWorkerChain.java

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for
+ * license information.
+ */
+package com.microsoft.azure.functions.middleware;
+
+import com.microsoft.azure.functions.ExecutionContext;
+
+public interface FunctionWorkerChain {
+    void doNext(ExecutionContext context) throws Exception;
+}

src/main/java/com/microsoft/azure/functions/middleware/FunctionWorkerMiddleware.java

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for
+ * license information.
+ */
+package com.microsoft.azure.functions.middleware;
+
+import com.microsoft.azure.functions.ExecutionContext;
+
+public interface FunctionWorkerMiddleware {
+    void invoke(ExecutionContext context, FunctionWorkerChain next) throws Exception;
+}