Extend AiServices to support SystemMessageProvider (#25)

This pull request includes several updates to the `langchain4j-kotlin`
project, focusing on dependency management, new features, and testing
improvements. The most important changes include adding new
dependencies, introducing a new interface for system message providers,
and updating the `pom.xml` files to reflect these changes.

### Dependency Management:
* Added `langchain4j` as an optional dependency in
`langchain4j-kotlin/pom.xml` and updated the main `pom.xml` to include
versions for `mockito` and `mockito-kotlin` dependencies.
[[1]](diffhunk://#diff-988dd67f6a0de416687ee39291f2713a8229de37918339f305c4ec8ae58e539bR19-R23)
[[2]](diffhunk://#diff-9c5fb3d1b7e3b0f54bc5c4182965c4fe1f9023d449017cece3005d3f90e8e4d8R104-R116)
* Removed `langchain4j` from the test scope in
`langchain4j-kotlin/pom.xml`.
* Added `mockito-kotlin` and `mockito-junit-jupiter` as test
dependencies in `langchain4j-kotlin/pom.xml`.

### New Features:
* Introduced a new type alias `ChatMemoryId` in `TypeAliases.kt`.
* Added `SystemMessageProvider` interface to provide system messages
based on chat memory identifiers.
* Created an extension function `systemMessageProvider` for `AiServices`
to set the system message provider.

### Testing Improvements:
* Added a new test class `ServiceWithSystemMessageProviderTest` to
verify the functionality of the `SystemMessageProvider`.

### Documentation:
* Updated the `README.md` to include the new `langchain4j` dependency.

### Miscellaneous:
* Updated the project name in the main `pom.xml` from "Aggregator" to
"Root".
* Added additional configuration for Maven plugins in `pom.xml` to
support new dependencies and improve build processes.
[[1]](diffhunk://#diff-9c5fb3d1b7e3b0f54bc5c4182965c4fe1f9023d449017cece3005d3f90e8e4d8R177-R179)
[[2]](diffhunk://#diff-9c5fb3d1b7e3b0f54bc5c4182965c4fe1f9023d449017cece3005d3f90e8e4d8L225-R274)

---------

Co-authored-by: Konstantin Pavlov <{ID}+{username}@users.noreply.github.com>

README.md

@@ -29,7 +29,12 @@ Add the following dependencies to your `pom.xml`:
         <version>[LATEST_VERSION]</version>
     </dependency>
 
-    <!-- Required Dependencies -->
+    <!-- Extra Dependencies -->
+    <dependency>
+      <groupId>dev.langchain4j</groupId>
+      <artifactId>langchain4j</artifactId>
+      <version>0.36.0</version>
+    </dependency>
     <dependency>
          <groupId>dev.langchain4j</groupId>
          <artifactId>langchain4j-open-ai</artifactId>

langchain4j-kotlin/pom.xml

@@ -16,6 +16,11 @@
             <groupId>dev.langchain4j</groupId>
             <artifactId>langchain4j-core</artifactId>
         </dependency>
+        <dependency>
+            <groupId>dev.langchain4j</groupId>
+            <artifactId>langchain4j</artifactId>
+            <optional>true</optional>
+        </dependency>
         <dependency>
             <groupId>org.jetbrains.kotlinx</groupId>
             <artifactId>kotlinx-coroutines-core-jvm</artifactId>
@@ -30,11 +35,7 @@
             <artifactId>junit-jupiter-api</artifactId>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>dev.langchain4j</groupId>
-            <artifactId>langchain4j</artifactId>
-            <scope>test</scope>
-        </dependency>
+
         <dependency>
             <groupId>dev.langchain4j</groupId>
             <artifactId>langchain4j-open-ai</artifactId>
@@ -45,6 +46,16 @@
             <artifactId>finchly</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito.kotlin</groupId>
+            <artifactId>mockito-kotlin</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>

langchain4j-kotlin/src/main/kotlin/me/kpavlov/langchain4j/kotlin/TypeAliases.kt

@@ -0,0 +1,3 @@
+package me.kpavlov.langchain4j.kotlin
+
+typealias ChatMemoryId = Any

langchain4j-kotlin/src/main/kotlin/me/kpavlov/langchain4j/kotlin/service/AiServicesExtensions.kt

@@ -0,0 +1,13 @@
+package me.kpavlov.langchain4j.kotlin.service
+
+import dev.langchain4j.service.AiServices
+
+/**
+ * Sets the system message provider for the AI services.
+ *
+ * @param provider The SystemMessageProvider that supplies system messages based on chat memory identifiers.
+ * @return The updated AiServices instance with the specified system message provider.
+ */
+public fun <T> AiServices<T>.systemMessageProvider(
+    provider: SystemMessageProvider,
+): AiServices<T> = this.systemMessageProvider(provider::getSystemMessage)

langchain4j-kotlin/src/main/kotlin/me/kpavlov/langchain4j/kotlin/service/SystemMessageProvider.kt

@@ -0,0 +1,16 @@
+package me.kpavlov.langchain4j.kotlin.service
+
+import me.kpavlov.langchain4j.kotlin.ChatMemoryId
+
+/**
+ * Interface for providing LLM system messages based on a given chat memory identifier.
+ */
+public interface SystemMessageProvider {
+    /**
+     * Provides a system message based on the given chat memory identifier.
+     *
+     * @param chatMemoryID Identifier for the chat memory used to generate the system message.
+     * @return A system prompt string associated with the provided chat memory identifier, maybe `null`
+     */
+    public fun getSystemMessage(chatMemoryID: ChatMemoryId): String?
+}

langchain4j-kotlin/src/test/kotlin/me/kpavlov/langchain4j/kotlin/service/ServiceWithSystemMessageProviderTest.kt

@@ -0,0 +1,47 @@
+package me.kpavlov.langchain4j.kotlin.service
+
+import assertk.assertThat
+import assertk.assertions.isEqualTo
+import dev.langchain4j.data.message.AiMessage
+import dev.langchain4j.data.message.SystemMessage
+import dev.langchain4j.model.chat.ChatLanguageModel
+import dev.langchain4j.model.output.Response
+import dev.langchain4j.service.AiServices
+import dev.langchain4j.service.UserMessage
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+import org.mockito.junit.jupiter.MockitoExtension
+
+@ExtendWith(MockitoExtension::class)
+class ServiceWithSystemMessageProviderTest {
+    lateinit var model: ChatLanguageModel
+
+    @Test
+    fun `Should use SystemMessageProvider`() {
+        model =
+            ChatLanguageModel {
+                assertThat(it.first()).isEqualTo(SystemMessage.from("You are helpful assistant"))
+                Response.from(AiMessage.from("I'm fine, thanks"))
+            }
+
+        val assistant =
+            AiServices
+                .builder(Assistant::class.java)
+                .systemMessageProvider(
+                    object : SystemMessageProvider {
+                        override fun getSystemMessage(chatMemoryID: Any): String =
+                            "You are helpful assistant"
+                    },
+                ).chatLanguageModel(model)
+                .build()
+
+        val response = assistant.askQuestion("How are you")
+        assertThat(response).isEqualTo("I'm fine, thanks")
+    }
+
+    private interface Assistant {
+        fun askQuestion(
+            @UserMessage question: String,
+        ): String
+    }
+}

pom.xml

@@ -6,7 +6,7 @@
     <artifactId>root</artifactId>
     <version>0.1.2-SNAPSHOT</version>
     <packaging>pom</packaging>
-    <name>LangChain4j-Kotlin :: Aggregator</name>
+    <name>LangChain4j-Kotlin :: Root</name>
     <description>Kotlin enhancements for LangChain4j</description>
     <url>https://github.com/kpavlov/langchain4j-kotlin</url>
 
@@ -41,18 +41,22 @@
     </scm>
 
     <properties>
+        <argLine/>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <kotlin.code.style>official</kotlin.code.style>
         <java.version>17</java.version>
         <kotlin.version>2.0.21</kotlin.version>
         <kotlin.compiler.jvmTarget>${java.version}</kotlin.compiler.jvmTarget>
         <java.compiler.release>${java.version}</java.compiler.release>
+        <java.compiler.source>${java.version}</java.compiler.source>
         <!-- Dependencies -->
         <awaitility.version>4.2.2</awaitility.version>
         <finchly.version>0.1.1</finchly.version>
         <junit.version>5.11.3</junit.version>
         <kotlinx.version>1.9.0</kotlinx.version>
         <langchain4j.version>0.36.0</langchain4j.version>
+        <mockito-kotlin.version>5.4.0</mockito-kotlin.version>
+        <mockito.version>5.14.2</mockito.version>
         <slf4j.version>2.0.16</slf4j.version>
     </properties>
 
@@ -97,6 +101,19 @@
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
+            <dependency>
+                <groupId>org.mockito</groupId>
+                <artifactId>mockito-bom</artifactId>
+                <version>${mockito.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.mockito.kotlin</groupId>
+                <artifactId>mockito-kotlin</artifactId>
+                <version>${mockito-kotlin.version}</version>
+                <scope>test</scope>
+            </dependency>
             <dependency>
                 <groupId>org.slf4j</groupId>
                 <artifactId>slf4j-simple</artifactId>
@@ -157,6 +174,9 @@
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-surefire-plugin</artifactId>
                     <version>3.5.2</version>
+                    <configuration>
+                        <argLine>@{argLine} -javaagent:${org.mockito:mockito-core:jar}</argLine>
+                    </configuration>
                 </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
@@ -222,22 +242,36 @@
                 <configuration>
                     <args>
                         <arg>-Xjsr305=strict</arg>
-                        <!--arg>-Werror</arg-->
+                        <!--<arg>-Werror</arg>-->
                     </args>
+                    <javaParameters>true</javaParameters>
                 </configuration>
             </plugin>
 
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-dependency-plugin</artifactId>
                 <executions>
+                    <execution>
+                        <id>properties</id>
+                        <goals>
+                            <goal>properties</goal>
+                        </goals>
+                    </execution>
                     <execution>
                         <goals>
                             <goal>analyze-only</goal>
                         </goals>
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <argLine>@{argLine} -javaagent:${org.mockito:mockito-core:jar}</argLine>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-failsafe-plugin</artifactId>