guice-bootstrap

KO | EN

gitlite — search

#python #java #python3 #arduino #golang #machine-learning #rust #html #flask #javascript #seismology #nodejs

guice-bootstrap

★ 12 Open GitHub ↗

Guice with JSR 250 Lifecycle annotations (@ PostConstruct and @ PreDestroy)

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

***Guice-bootstrap ([`org.embulk:guice-bootstrap`](https://central.sonatype.com/artifact/org.embulk/guice-bootstrap)) is no longer maintained.***

If you wanted to use this updated, maintain your fork with taking care of its license.

This is licensed under the [Apache License, Version 2.0](https://www.apache.org/licenses/LICENSE-2.0), but it has some modified copies from [Airlift](https://github.com/airlift/airlift)'s bootstrap.

----

# Guice-bootstrap

Guice-bootstrap is an extension of [Guice](https://github.com/google/guice) that adds support for JSR 250 Life Cycle annotations.

**@PostConstruct** annotation is used on methods that need to get executed after dependency injection is done to perform any initialization.

**@PreDestroy** annotation is used on methods that are called before the application shuts down.

## PostConstruct

Methods with `@PostConstruct` annotation are called after all depedency injection is done.

```java
import javax.annotation.PostConstruct;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

class MyService implements Runnable
{
    private final ExecutorService executor = Executors.newSingleThreadExecutor();

@PostConstruct
    public void start() {
        executor.submit(() -> { ... });
    }
}
```

## PreDestroy

Methods with `@PreDestroy` annotation are called after the application shuts down.

```java
import javax.annotation.PreDestroy;
import java.io.File;
import java.util.ArrayList;
import java.util.List;

class MyService implements Runnable
{
    private final List<File> files = new ArrayList<>();

@PreDestroy
    public void cleanup() {
        files.stream().forEach(file -> file.delete());
    }
}
```

## Bootstrap

**Bootstrap** is the main class to use guice-bootstrap.

```java
Injector injector = new Bootstrap()
    .addModules(new MyGuiceModule1(), new MyGuiceModule2(), ...)
    .addModules(new MyGuiceModule3(), new MyGuiceModule4(), ...)
    .initialize();
```

### Overriding bindings

**Bootstrap.overrideModulesWith** method allows you to override bindings. This is useful to customize bindings defined by a base class.

```java
// The base class
public class MyService {
    public Bootstrap bootstrap()
    {
        return new Bootstrap()
            .addModules(new MyGuiceModule1(), new MyGuiceModule2(), ...)
            .addModules(new MyGuiceModule3(), new MyGuiceModule4(), ...)
            ;
    }

public void start()
    {
        Injector injector = bootstrap().initialize();
        ...
    }
}

// Extending class that overrides some bindings
public class MyExtendedService extend MyService {
    @Override
    public Bootstrap bootstrap()
    {
        return super()
            .overrideModulesWith(new MyGuiceModule4(), ...)
            ;
    }
}
```

## CloseableInjector

`Bootstrap.initialize()` sets up a shutdown hook to the Java VM (@Runtime.addShutdownHook`). It ensures that PostDestroy methods are called when Java VM exits even if it's killed by a SIGTERM or Ctrl-C.

But if you want to control the exact timing of shutdown, you can use `Bootstrap.initializeCloseable()` instead. It returns **CloseableInjector** which implements Injector and Closeable interfaces.

```java
Bootstrap bootstrap = new Bootstrap()
    .addModules(...);

try (CloseableInjector injector = bootstrap.initializeCloseable()) {
    ...
}
```

guice-bootstrap

Explore Similar Repositories

Was this content helpful?

Recent Feedback

Download README