Remove Lombok in langchain4j module (langchain4j#2063)

## Issue
Contributes to langchain4j#1636 

## Change

- Remove Lombok in langchain4j module: Introduces inline `equals`,
`hashCode`, and `toString` methods instead of Lombok-generated methods
for improved flexibility and customization.
- Reformat code to improve readability and consistency.
- Remove unused imports and replace direct class loading with specific
imports for better clarity.
- Added `@EnabledIfEnvironmentVariable` condition to integration tests,
relaying on the presence of the OPENAI_API_KEY environment variable


## General checklist
- [x] There are no breaking changes
- [ ] I have added unit and integration tests for my change
- [x] I have manually run all the unit and integration tests in the
module I have added/changed, and they are all green
- [ ] I have manually run all the unit and integration tests in the
[core](https://github.com/langchain4j/langchain4j/tree/main/langchain4j-core)
and
[main](https://github.com/langchain4j/langchain4j/tree/main/langchain4j)
modules, and they are all green
- [ ] I have added/updated the
[documentation](https://github.com/langchain4j/langchain4j/tree/main/docs/docs)
- [ ] I have added an example in the [examples
repo](https://github.com/langchain4j/langchain4j-examples) (only for
"big" features)
- [ ] I have added/updated [Spring Boot
starter(s)](https://github.com/langchain4j/langchain4j-spring) (if
applicable)

langchain4j/pom.xml

@@ -13,7 +13,9 @@
 
     <artifactId>langchain4j</artifactId>
     <name>LangChain4j</name>
-    <description>Java implementation of LangChain: Integrate your Java application with countless AI tools and services smoothly</description>
+    <description>Java implementation of LangChain: Integrate your Java application with countless AI
+        tools and services smoothly
+    </description>
 
     <dependencies>
 
@@ -28,12 +30,6 @@
             <artifactId>opennlp-tools</artifactId>
         </dependency>
 
-        <dependency>
-            <groupId>org.projectlombok</groupId>
-            <artifactId>lombok</artifactId>
-            <scope>provided</scope>
-        </dependency>
-
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>

langchain4j/src/main/java/dev/langchain4j/chain/ConversationalChain.java

@@ -5,7 +5,6 @@
 import dev.langchain4j.memory.chat.MessageWindowChatMemory;
 import dev.langchain4j.model.chat.ChatLanguageModel;
 import dev.langchain4j.service.AiServices;
-import lombok.Builder;
 
 import static dev.langchain4j.data.message.UserMessage.userMessage;
 import static dev.langchain4j.internal.ValidationUtils.ensureNotBlank;
@@ -22,12 +21,15 @@ public class ConversationalChain implements Chain<String, String> {
     private final ChatLanguageModel chatLanguageModel;
     private final ChatMemory chatMemory;
 
-    @Builder
     private ConversationalChain(ChatLanguageModel chatLanguageModel, ChatMemory chatMemory) {
         this.chatLanguageModel = ensureNotNull(chatLanguageModel, "chatLanguageModel");
         this.chatMemory = chatMemory == null ? MessageWindowChatMemory.withMaxMessages(10) : chatMemory;
     }
 
+    public static ConversationalChainBuilder builder() {
+        return new ConversationalChainBuilder();
+    }
+
     @Override
     public String execute(String userMessage) {
 
@@ -39,4 +41,30 @@ public String execute(String userMessage) {
 
         return aiMessage.text();
     }
+
+    public static class ConversationalChainBuilder {
+        private ChatLanguageModel chatLanguageModel;
+        private ChatMemory chatMemory;
+
+        ConversationalChainBuilder() {
+        }
+
+        public ConversationalChainBuilder chatLanguageModel(ChatLanguageModel chatLanguageModel) {
+            this.chatLanguageModel = chatLanguageModel;
+            return this;
+        }
+
+        public ConversationalChainBuilder chatMemory(ChatMemory chatMemory) {
+            this.chatMemory = chatMemory;
+            return this;
+        }
+
+        public ConversationalChain build() {
+            return new ConversationalChain(this.chatLanguageModel, this.chatMemory);
+        }
+
+        public String toString() {
+            return "ConversationalChain.ConversationalChainBuilder(chatLanguageModel=" + this.chatLanguageModel + ", chatMemory=" + this.chatMemory + ")";
+        }
+    }
 }

langchain4j/src/main/java/dev/langchain4j/data/document/loader/FileSystemDocumentLoader.java

@@ -1,7 +1,7 @@
 package dev.langchain4j.data.document.loader;
 
-import dev.langchain4j.data.document.Document;
 import dev.langchain4j.data.document.BlankDocumentException;
+import dev.langchain4j.data.document.Document;
 import dev.langchain4j.data.document.DocumentLoader;
 import dev.langchain4j.data.document.DocumentParser;
 import dev.langchain4j.data.document.parser.TextDocumentParser;

langchain4j/src/main/java/dev/langchain4j/data/document/parser/TextDocumentParser.java

@@ -1,14 +1,12 @@
 package dev.langchain4j.data.document.parser;
 
-import dev.langchain4j.data.document.Document;
 import dev.langchain4j.data.document.BlankDocumentException;
+import dev.langchain4j.data.document.Document;
 import dev.langchain4j.data.document.DocumentParser;
 
-import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.nio.charset.Charset;
 
-import static dev.langchain4j.internal.Utils.isNullOrBlank;
 import static dev.langchain4j.internal.ValidationUtils.ensureNotNull;
 import static java.nio.charset.StandardCharsets.UTF_8;
 

langchain4j/src/main/java/dev/langchain4j/data/document/splitter/HierarchicalDocumentSplitter.java

@@ -5,7 +5,6 @@
 import dev.langchain4j.data.document.Metadata;
 import dev.langchain4j.data.segment.TextSegment;
 import dev.langchain4j.model.Tokenizer;
-import lombok.Getter;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -14,7 +13,9 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static dev.langchain4j.internal.Utils.firstChars;
-import static dev.langchain4j.internal.ValidationUtils.*;
+import static dev.langchain4j.internal.ValidationUtils.ensureBetween;
+import static dev.langchain4j.internal.ValidationUtils.ensureGreaterThanZero;
+import static dev.langchain4j.internal.ValidationUtils.ensureNotNull;
 
 /**
  * Base class for hierarchical document splitters.
@@ -23,9 +24,14 @@
  * when a single segment is too long.
  */
 public abstract class HierarchicalDocumentSplitter implements DocumentSplitter {
-    @Getter(lazy = true)
-    private final HierarchicalDocumentSplitter overlapSentenceSplitter =
-            new DocumentBySentenceSplitter(1, 0, null, null);
+    private HierarchicalDocumentSplitter overlapSentenceSplitter;
+
+    private HierarchicalDocumentSplitter getOverlapSentenceSplitter() {
+        if (overlapSentenceSplitter == null) {
+            overlapSentenceSplitter = new DocumentBySentenceSplitter(1, 0, null, null);
+        }
+        return overlapSentenceSplitter;
+    }
 
     private static final String INDEX = "index";
 

langchain4j/src/main/java/dev/langchain4j/service/Result.java

@@ -1,10 +1,9 @@
 package dev.langchain4j.service;
 
-import dev.langchain4j.service.tool.ToolExecution;
 import dev.langchain4j.model.output.FinishReason;
 import dev.langchain4j.model.output.TokenUsage;
 import dev.langchain4j.rag.content.Content;
-import lombok.Builder;
+import dev.langchain4j.service.tool.ToolExecution;
 
 import java.util.List;
 
@@ -17,7 +16,7 @@
  * such as {@link TokenUsage} and sources ({@link Content}s retrieved during RAG).
  *
  * @param <T> The type of the content. Can be of any return type supported by AI Services,
- *           such as String, Enum, MyCustomPojo, etc.
+ *            such as String, Enum, MyCustomPojo, etc.
  */
 public class Result<T> {
 
@@ -27,7 +26,6 @@ public class Result<T> {
     private final FinishReason finishReason;
     private final List<ToolExecution> toolExecutions;
 
-    @Builder
     public Result(T content, TokenUsage tokenUsage, List<Content> sources, FinishReason finishReason, List<ToolExecution> toolExecutions) {
         this.content = ensureNotNull(content, "content");
         this.tokenUsage = tokenUsage;
@@ -36,6 +34,10 @@ public Result(T content, TokenUsage tokenUsage, List<Content> sources, FinishRea
         this.toolExecutions = copyIfNotNull(toolExecutions);
     }
 
+    public static <T> ResultBuilder<T> builder() {
+        return new ResultBuilder<T>();
+    }
+
     public T content() {
         return content;
     }
@@ -55,4 +57,48 @@ public FinishReason finishReason() {
     public List<ToolExecution> toolExecutions() {
         return toolExecutions;
     }
+
+    public static class ResultBuilder<T> {
+        private T content;
+        private TokenUsage tokenUsage;
+        private List<Content> sources;
+        private FinishReason finishReason;
+        private List<ToolExecution> toolExecutions;
+
+        ResultBuilder() {
+        }
+
+        public ResultBuilder<T> content(T content) {
+            this.content = content;
+            return this;
+        }
+
+        public ResultBuilder<T> tokenUsage(TokenUsage tokenUsage) {
+            this.tokenUsage = tokenUsage;
+            return this;
+        }
+
+        public ResultBuilder<T> sources(List<Content> sources) {
+            this.sources = sources;
+            return this;
+        }
+
+        public ResultBuilder<T> finishReason(FinishReason finishReason) {
+            this.finishReason = finishReason;
+            return this;
+        }
+
+        public ResultBuilder<T> toolExecutions(List<ToolExecution> toolExecutions) {
+            this.toolExecutions = toolExecutions;
+            return this;
+        }
+
+        public Result<T> build() {
+            return new Result<T>(this.content, this.tokenUsage, this.sources, this.finishReason, this.toolExecutions);
+        }
+
+        public String toString() {
+            return "Result.ResultBuilder(content=" + this.content + ", tokenUsage=" + this.tokenUsage + ", sources=" + this.sources + ", finishReason=" + this.finishReason + ", toolExecutions=" + this.toolExecutions + ")";
+        }
+    }
 }

langchain4j/src/main/java/dev/langchain4j/service/output/DefaultOutputParserFactory.java

@@ -5,7 +5,12 @@
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.LocalTime;
-import java.util.*;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
 
 class DefaultOutputParserFactory implements OutputParserFactory {
 

langchain4j/src/main/java/dev/langchain4j/store/embedding/inmemory/InMemoryEmbeddingStore.java

@@ -4,19 +4,32 @@
 import dev.langchain4j.data.embedding.Embedding;
 import dev.langchain4j.data.segment.TextSegment;
 import dev.langchain4j.spi.store.embedding.inmemory.InMemoryEmbeddingStoreJsonCodecFactory;
-import dev.langchain4j.store.embedding.*;
+import dev.langchain4j.store.embedding.CosineSimilarity;
+import dev.langchain4j.store.embedding.EmbeddingMatch;
+import dev.langchain4j.store.embedding.EmbeddingSearchRequest;
+import dev.langchain4j.store.embedding.EmbeddingSearchResult;
+import dev.langchain4j.store.embedding.EmbeddingStore;
+import dev.langchain4j.store.embedding.RelevanceScore;
 import dev.langchain4j.store.embedding.filter.Filter;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Objects;
+import java.util.PriorityQueue;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.stream.IntStream;
 
 import static dev.langchain4j.internal.Utils.randomUUID;
-import static dev.langchain4j.internal.ValidationUtils.*;
+import static dev.langchain4j.internal.ValidationUtils.ensureNotBlank;
+import static dev.langchain4j.internal.ValidationUtils.ensureNotEmpty;
+import static dev.langchain4j.internal.ValidationUtils.ensureNotNull;
 import static dev.langchain4j.spi.ServiceHelper.loadFactories;
 import static java.nio.file.StandardOpenOption.CREATE;
 import static java.nio.file.StandardOpenOption.TRUNCATE_EXISTING;

langchain4j/src/test/java/dev/langchain4j/data/document/splitter/SegmentBuilderTest.java

@@ -51,7 +51,7 @@ public void test_reset() {
         builder.reset();
 
         assertThat(builder.isNotEmpty()).isFalse();
-        assertThat(builder.getSize()).isEqualTo(0);
+        assertThat(builder.getSize()).isZero();
         assertThat(builder.toString()).isEqualTo("");
     }
 
@@ -70,4 +70,4 @@ public void test_append_prepend() {
             assertThat(builder.toString()).isEqualTo("Hello world");
         }
     }
-}
+}

langchain4j/src/test/java/dev/langchain4j/rag/query/router/LanguageModelQueryRouterIT.java

@@ -4,6 +4,7 @@
 import dev.langchain4j.model.openai.OpenAiChatModel;
 import dev.langchain4j.rag.content.retriever.ContentRetriever;
 import dev.langchain4j.rag.query.Query;
+import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
@@ -19,6 +20,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 @ExtendWith(MockitoExtension.class)
+@EnabledIfEnvironmentVariable(named = "OPENAI_API_KEY", matches = ".+")
 class LanguageModelQueryRouterIT {
 
     @Mock

langchain4j/src/test/java/dev/langchain4j/rag/query/transformer/CompressingQueryTransformerIT.java

@@ -7,6 +7,7 @@
 import dev.langchain4j.model.openai.OpenAiChatModel;
 import dev.langchain4j.rag.query.Metadata;
 import dev.langchain4j.rag.query.Query;
+import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -18,6 +19,7 @@
 import static java.util.Arrays.asList;
 import static org.assertj.core.api.Assertions.assertThat;
 
+@EnabledIfEnvironmentVariable(named = "OPENAI_API_KEY", matches = ".+")
 class CompressingQueryTransformerIT {
 
     @ParameterizedTest

langchain4j/src/test/java/dev/langchain4j/rag/query/transformer/ExpandingQueryTransformerIT.java

@@ -3,6 +3,7 @@
 import dev.langchain4j.model.chat.ChatLanguageModel;
 import dev.langchain4j.model.openai.OpenAiChatModel;
 import dev.langchain4j.rag.query.Query;
+import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -12,6 +13,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+@EnabledIfEnvironmentVariable(named = "OPENAI_API_KEY", matches = ".+")
 class ExpandingQueryTransformerIT {
 
     @ParameterizedTest
@@ -49,4 +51,4 @@ static Stream<Arguments> should_expand_query() {
                 // TODO add more models
         );
     }
-}
+}