From 6df0f5517c8aad681dd5e16b4c4bb5e5ba1147d0 Mon Sep 17 00:00:00 2001
From: John Oliver <1615532+johnoliver@users.noreply.github.com>
Date: Tue, 13 Feb 2024 21:21:48 +0000
Subject: [PATCH] Java: add a priority order to hook invocations. Remove
 withInvocationContext (#5004)

### Motivation and Context

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### Description

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### Contribution Checklist

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- [ ] The code builds clean without any errors or warnings
- [ ] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [ ] All unit tests pass, and I have added new tests where possible
- [ ] I didn't break anyone :smile:
---
 .../semantickernel/hooks/KernelHook.java      | 14 ++++++-
 .../semantickernel/hooks/KernelHooks.java     | 42 ++++++++++++-------
 .../orchestration/FunctionInvocation.java     | 13 ------
 3 files changed, 39 insertions(+), 30 deletions(-)

diff --git a/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHook.java b/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHook.java
index 535727e391..be649fa47b 100644
--- a/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHook.java
+++ b/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHook.java
@@ -6,7 +6,19 @@ import java.util.List;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
-public interface KernelHook<T extends KernelHookEvent> extends Predicate<KernelHookEvent>, Function<T, T> {
+public interface KernelHook<T extends KernelHookEvent> extends Predicate<KernelHookEvent>,
+    Function<T, T> {
+
+    /**
+     * The priority of the hook. The default priority is 50. The priority is used to determine the
+     * order in which hooks that accept the same event type are executed, lower priorities are executed first. No ordering is
+     * guaranteed for hooks with the same priority.
+     *
+     * @return the priority of the hook
+     */
+    default int getPriority() {
+        return 50;
+    }
 
     interface FunctionInvokingHook extends KernelHook<FunctionInvokingEvent> {
 
diff --git a/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHooks.java b/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHooks.java
index e7cd3f931e..f47bb7fbcd 100644
--- a/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHooks.java
+++ b/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/hooks/KernelHooks.java
@@ -1,18 +1,19 @@
 package com.microsoft.semantickernel.hooks;
 
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.UUID;
-import java.util.function.Function;
-
-import javax.annotation.Nullable;
-
 import com.microsoft.semantickernel.hooks.KernelHook.FunctionInvokedHook;
 import com.microsoft.semantickernel.hooks.KernelHook.FunctionInvokingHook;
 import com.microsoft.semantickernel.hooks.KernelHook.PreChatCompletionHook;
 import com.microsoft.semantickernel.hooks.KernelHook.PromptRenderedHook;
 import com.microsoft.semantickernel.hooks.KernelHook.PromptRenderingHook;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.SortedSet;
+import java.util.TreeSet;
+import java.util.UUID;
+import java.util.function.Function;
+import javax.annotation.Nullable;
 
 public class KernelHooks {
 
@@ -37,7 +38,7 @@ public class KernelHooks {
     public UnmodifiableKernelHooks unmodifiableClone() {
         return new UnmodifiableKernelHooks(this);
     }
-    
+
     private Map<String, KernelHook<?>> getHooks() {
         return Collections.unmodifiableMap(hooks);
     }
@@ -69,7 +70,11 @@ public class KernelHooks {
 
     @SuppressWarnings("unchecked")
     public <T extends KernelHookEvent> T executeHooks(T event) {
-        for (KernelHook<?> hook : hooks.values()) {
+        SortedSet<KernelHook<?>> hooks = new TreeSet<>(Comparator.comparingInt(KernelHook::getPriority));
+
+        hooks.addAll(this.hooks.values());
+
+        for (KernelHook<?> hook : hooks) {
             if (hook.test(event)) {
                 // unchecked cast
                 event = ((KernelHook<T>) hook).apply(event);
@@ -110,33 +115,38 @@ public class KernelHooks {
     }
 
     public static class UnmodifiableKernelHooks extends KernelHooks {
-            
+
         private UnmodifiableKernelHooks(KernelHooks kernelHooks) {
             super(kernelHooks);
         }
 
         @Override
-        public String addFunctionInvokingHook(Function<FunctionInvokingEvent, FunctionInvokingEvent> function) {
+        public String addFunctionInvokingHook(
+            Function<FunctionInvokingEvent, FunctionInvokingEvent> function) {
             throw new UnsupportedOperationException("unmodifiable instance of KernelHooks");
         }
 
         @Override
-        public String addFunctionInvokedHook(Function<FunctionInvokedEvent<?>, FunctionInvokedEvent<?>> function) {
+        public String addFunctionInvokedHook(
+            Function<FunctionInvokedEvent<?>, FunctionInvokedEvent<?>> function) {
             throw new UnsupportedOperationException("unmodifiable instance of KernelHooks");
         }
 
         @Override
-        public String addPreChatCompletionHook(Function<PreChatCompletionEvent, PreChatCompletionEvent> function) {
+        public String addPreChatCompletionHook(
+            Function<PreChatCompletionEvent, PreChatCompletionEvent> function) {
             throw new UnsupportedOperationException("unmodifiable instance of KernelHooks");
         }
 
         @Override
-        public String addPromptRenderedHook(Function<PromptRenderedEvent, PromptRenderedEvent> function) {
+        public String addPromptRenderedHook(
+            Function<PromptRenderedEvent, PromptRenderedEvent> function) {
             throw new UnsupportedOperationException("unmodifiable instance of KernelHooks");
         }
 
         @Override
-        public String addPromptRenderingHook(Function<PromptRenderingEvent, PromptRenderingEvent> function) {
+        public String addPromptRenderingHook(
+            Function<PromptRenderingEvent, PromptRenderingEvent> function) {
             throw new UnsupportedOperationException("unmodifiable instance of KernelHooks");
         }
 
diff --git a/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/orchestration/FunctionInvocation.java b/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/orchestration/FunctionInvocation.java
index 811578e3fe..d52b50840f 100644
--- a/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/orchestration/FunctionInvocation.java
+++ b/java/semantickernel-api/src/main/java/com/microsoft/semantickernel/orchestration/FunctionInvocation.java
@@ -129,19 +129,6 @@ public class FunctionInvocation<T> extends Mono<FunctionResult<T>> {
         return this;
     }
 
-    public FunctionInvocation<T> withInvocationContext(
-        @Nullable InvocationContext invocationContext) {
-        if (invocationContext == null) {
-            return this;
-        }
-        withTypes(invocationContext.getContextVariableTypes());
-        withToolCallBehavior(invocationContext.getToolCallBehavior());
-        withPromptExecutionSettings(invocationContext.getPromptExecutionSettings());
-        addKernelHooks(invocationContext.getKernelHooks());
-        return this;
-    }
-
-
     @Override
     public void subscribe(CoreSubscriber<? super FunctionResult<T>> coreSubscriber) {
         performSubscribe(