tessl/maven-dev-langchain4j--langchain4j-ollama
Java integration library enabling LangChain4j applications to use Ollama's local language models with support for chat, streaming, embeddings, and advanced reasoning features
spi.mddocs/
Service Provider Interface (SPI)
The langchain4j-ollama module provides SPI (Service Provider Interface) interfaces for custom builder factory implementations. These interfaces enable framework integrations and dependency injection scenarios.
Overview
SPI interfaces follow the Java ServiceLoader pattern, allowing custom implementations to provide builder instances. Each model class has a corresponding factory interface.
Common use cases:
- Dependency injection frameworks (Spring, CDI, Guice)
- Custom builder configuration and initialization
- Framework-level model management
- Testing and mocking infrastructure
OllamaChatModelBuilderFactory
Factory interface for creating OllamaChatModel builder instances.
Interface Signature
package dev.langchain4j.model.ollama.spi;
import dev.langchain4j.model.ollama.OllamaChatModel;
import java.util.function.Supplier;
public interface OllamaChatModelBuilderFactory
extends Supplier<OllamaChatModel.OllamaChatModelBuilder>Thread Safety: Implementations should be stateless and thread-safe
Method
OllamaChatModel.OllamaChatModelBuilder get()Returns a new builder instance for OllamaChatModel.
Returns: Fresh OllamaChatModelBuilder instance
- Never null
- Each call returns new instance
Thread Safety: Must be safe for concurrent calls
Example Implementation:
public class CustomOllamaChatModelBuilderFactory
implements OllamaChatModelBuilderFactory {
@Override
public OllamaChatModel.OllamaChatModelBuilder get() {
return OllamaChatModel.builder()
.baseUrl(loadFromConfig("ollama.baseUrl"))
.timeout(Duration.ofMinutes(5))
.logRequests(true);
}
}ServiceLoader Registration
Create file META-INF/services/dev.langchain4j.model.ollama.spi.OllamaChatModelBuilderFactory:
com.example.CustomOllamaChatModelBuilderFactoryLoading via ServiceLoader
import dev.langchain4j.model.ollama.spi.OllamaChatModelBuilderFactory;
import java.util.ServiceLoader;
ServiceLoader<OllamaChatModelBuilderFactory> loader =
ServiceLoader.load(OllamaChatModelBuilderFactory.class);
OllamaChatModelBuilderFactory factory = loader.findFirst()
.orElseThrow(() -> new IllegalStateException("No factory found"));
OllamaChatModel model = factory.get()
.modelName("llama2")
.build();Best Practices
1. Provide Sensible Defaults
@Override
public OllamaChatModel.OllamaChatModelBuilder get() {
return OllamaChatModel.builder()
.baseUrl("http://localhost:11434") // Default URL
.timeout(Duration.ofMinutes(5)) // Reasonable timeout
.maxRetries(3); // Automatic retries
}2. Thread Safety
// Factories should be stateless and thread-safe
public class ThreadSafeFactory implements OllamaChatModelBuilderFactory {
@Override
public OllamaChatModel.OllamaChatModelBuilder get() {
// Returns new builder instance each time - thread safe
return OllamaChatModel.builder()
.baseUrl(getConfiguredUrl());
}
private String getConfiguredUrl() {
// Read from thread-safe configuration source
return ConfigurationManager.getOllamaUrl();
}
}See Also
- Chat Models - OllamaChatModel
- Embedding Model - OllamaEmbeddingModel
- Java ServiceLoader - Standard Java SPI mechanism
Install with Tessl CLI
npx tessl i tessl/maven-dev-langchain4j--langchain4j-ollama