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https://github.com/skydoves/chamber
⚖️ A lightweight Android lifecycle-aware and thread-safe pipeline for communicating between components with custom scopes.
https://github.com/skydoves/chamber
android architecture chamber dataflow kotlin lifecycle-aware scope skydoves
Last synced: 7 days ago
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⚖️ A lightweight Android lifecycle-aware and thread-safe pipeline for communicating between components with custom scopes.
- Host: GitHub
- URL: https://github.com/skydoves/chamber
- Owner: skydoves
- License: apache-2.0
- Created: 2019-07-23T09:36:47.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2021-05-17T10:50:30.000Z (over 3 years ago)
- Last Synced: 2024-10-23T01:20:17.803Z (16 days ago)
- Topics: android, architecture, chamber, dataflow, kotlin, lifecycle-aware, scope, skydoves
- Language: Kotlin
- Homepage:
- Size: 255 KB
- Stars: 186
- Watchers: 5
- Forks: 14
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
- Codeowners: .github/CODEOWNERS
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README
# Chamber
A lightweight Android lifecycle-aware and thread-safe pipeline for communicating between components with custom scopes.
>
Android components are essential building blocks of an Android application.
These independent components are very loosely coupled. The benefit is that they are really independently reusable, but it makes to hard communicate with each other.
>
The goal of this library is making easier to communicate and flow data with each other component like Activity, Fragment, Services, etc. And we can deliver data on each component easily and clear data on memory automatically following lifecycles. Also using custom scopes that are lifecycle aware makes developers can designate scoped data holder on their taste.
## When is useful?
>When we need to hold some immutable data and it needs to be synchronized as the same data at each other components. For example, there is `Activity A`, `Activity B`, `Activity C`. And we need to use the same data in all Activity A~C that can be changed. Then we should pass a parcelable data A to B and B to C and getting the changed data reversely through onActivityResult.
>Then how about the communication with fragments? We can solve it by implementing an interface, singleton pattern, observer pattern or etc, but the data flow would be quite complicated. Chamber helps to simplify those communications between Chamber scope owners.
## Including in your project
[](https://search.maven.org/search?q=g:%22com.github.skydoves%22%20AND%20a:%chamber%22)
[](https://jitpack.io/#skydoves/chamber)
### Gradle
Add below codes to your **root** `build.gradle` file (not your module build.gradle file).
```Gradle
allprojects {
repositories {
mavenCentral()
}
}
```
And add a dependency code to your module's build.gradle file.
```gradle
dependencies {
implementation "com.github.skydoves:chamber:1.0.3"
}
```
## SNAPSHOT
[](https://oss.sonatype.org/content/repositories/snapshots/com/github/skydoves/chamber/)
Snapshots of the current development version of Chamber are available, which track [the latest versions](https://oss.sonatype.org/content/repositories/snapshots/com/github/skydoves/chamber/).
```Gradle
repositories {
maven { url 'https://oss.sonatype.org/content/repositories/snapshots/' }
}
```
## Usage
Chamber is a lightweight lifecycle-aware pipeline based on scopes.
### ChamberScope
The basic usage is creating a customized scope annotation using a `@ChamberScope` annotation.
`@ChamberScope` is used to build custom scopes that are lifecycle aware. Each scope will be used as a pipeline via `ChamberProperty` and it will be managed by the lifecycle stack. It should be annotated on classes (activity, fragment, repository, or any classes) that has `ChamberProperty` fields.
```kotlin
@ChamberScope
@Retention(AnnotationRetention.RUNTIME)
annotation class UserScope
```
### ChamberProperty
ChamberProperty is an interactive class to the internal Chamber data holder and a lifecycleObserver that can be observable.
It should be used with `@ShareProperty` annotation that has a key name. If we want to use the same synchronized value on the same custom scope in different classes, we should use the same key.
```kotlin
@ShareProperty(key = "name") // name is a key name.
private var username = ChamberProperty("skydoves") // ChamberProperty can be initialized with any object.
```
#### setValue
Using the `setValue` method, we can change the `ChamberProperty`'s value.
```kotlin
username.value = "user name is changed"
```
#### postValue
Posts a task to a main thread to set the given value. So if you have a following code executed in the main thread:
```kotlin
username.postValue("a")
username.value = "b"
```
The value `b` would be set at first and later the main thread would override it with the value `a`.
If you called this method multiple times before a main thread executed a posted task, only the last value would be dispatched.
#### observe
We can observe the value is changed using the `observe` method. There is only one observer that can be registered on the property. The events are dispatched on the main thread. If `ChamberProperty` already has data set, it will be delivered to the observer.
```kotlin
username.observe {
log("data is changed to $it")
}
```
### ShareLifecycle
Chamber synchronizes and dispatches `ChamberProperty`s that are included in the same scope and had the same key thread-safety. We should pass two arguments; `scopeOwner` that is annotated with a custom scope, `lifecycleOwner` that manages `ChamberProperty`s lifecycles for destroying. Here is an example of _MainActivity_ and _SecondActivity_.
#### MainActivity
If `Chamber.shareLifecycle` method is called, the `name` property that has `nickname` key will be managed by Chamber and Chamber will observe the _MainActivity_'s lifecycle state.
```kotlin
@UserScope // custom scope
class MainActivity : AppCompatActivity() {
@ShareProperty(key = "nickname")
private var name = ChamberProperty("skydoves")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
Chamber.shareLifecycle(scopeOwner = this, lifecycleOwner = this)
name.observe { log($it) }
name.value = "name value is changed"
startActivity(SecondActivity::class.java)
}
}
```
```gradle
[output]:
=> skydoves
=> name value is changed
```
#### MainActivity -> SecondActivity
_MainActivity_ starts _SecondActivity_ using startActivity.
__Chamber__ will observe the _SecondActivity_'s lifecycle state. And the `name` property's value on the
_SecondActivity_ will be synchronized by __Chamber__ when `shareLifecycle` method is called.
```kotlin
@UserScope
class SecondActivity : AppCompatActivity() {
@ShareProperty(key = "nickname")
private var name = ChamberProperty("skydoves")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_second)
Chamber.shareLifecycle(scopeOwner = this, lifecycleOwner = this)
name.observe { log($it) }
name.value = "changed in SecondActivity"
}
}
```
```gradle
[output]:
=> name value is changed
=> changed in SecondActivity
```
### The process of exiting scope
#### SeondActivity -> MainActivity
Following the about example, what if we call the `finish()` method in _SecondActivity_ and we come back to the _MainActivity_.
when _SecondActivity_'s lifecycle state is `onDestroy`, __Chamber__ will not manage anymore with the _SecondActivity_'s `ChamberProperty` and not observe lifecycle state.
And when _MainActivity_'s lifecycle state is `onResume`, __Chamber__ will dispatch the `ChamberProperty`'s value in _MainActivity_.
```kotlin
@UserScope
class MainActivity : AppCompatActivity() {
@ShareProperty(key = "nickname")
private var name = ChamberProperty("skydoves")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_second)
Chamber.shareLifecycle(scopeOwner = this, lifecycleOwner = this)
name.observe { log($it) }
name.value = "name value is changed"
startActivity(SecondActivity::class.java)
}
}
```
```gradle
[output]:
=> changed in SecondActivity
```
#### Destroying a scope
After all lifecycle owners are destroyed (All lifecycleOwners are popped from the __Chamber__'s lifecycle stack), all of the custom scope data will be cleared in the internal Chamber.
### Usage with ViewModel
Architecturally, UI components should do work relate to UI works.
So we can delegate the scope owner to other classes.
```kotlin
@UserScope // custom scope
class MainActivityViewModel : ViewModel() {
@ShareProperty(key = UserScope.nickname)
var username = ChamberProperty("skydoves")
@PropertyObserver(key = UserScope.nickname)
fun usernameObserver(value: String) {
Log.d("MainActivityViewModel", "usernameObserver: $value")
}
}
```
```kotlin
class MainActivity : AppCompatActivity() {
private val viewModel = MainActivityViewModel()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
Chamber.shareLifecycle(scopeOwner = viewModel, lifecycleOwner = this)
}
```
### PropertyObserver
`PropertyObserver` annotation used to observe value changes by `ChamberProperty` that has the same `key` value. This annotation only works with a method that in a scoped class. A method that is annotated with `PropertyObserver` will be invoked, whenever the value changes and receive the value as a parameter. The method must have one parameter and the type must same as the generic of the `ChamberProperty`.
Here is an example of usages in a ViewModel.
```kotlin
@UserScope // custom scope
class MainActivityViewModel : ViewModel() {
@ShareProperty(key = UserScope.nickname)
var username = ChamberProperty("skydoves")
@PropertyObserver(key = UserScope.nickname)
fun usernameObserver(value: String) {
Log.d("MainActivityViewModel", "usernameObserver: $value")
}
}
```
Here is an example of usages in an Activity.
```kotlin
@UserScope
class MainActivity : AppCompatActivity() {
@ShareProperty(key = UserScope.nickname)
private var username = chamberProperty("skydoves")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
shareLifecycle()
username.observe { Log.d("SecondActivity", "observed data: $it") }
username.value = "skydoves on SecondActivity"
}
@PropertyObserver(key = UserScope.nickname)
fun nickNameObserver(nickname: String) {
Log.d("MainActivity", "nickNameObserver: $nickname")
}
}
```
## Find this library useful? :heart:
Support it by joining __[stargazers](https://github.com/skydoves/chamber/stargazers)__ for this repository. :star:
## Design License
I designed flowcharts using [UXFlow](https://uxflow.co/), it is following [Attribution 4.0 International (CC BY 4.0)](https://creativecommons.org/licenses/by/4.0/legalcode).
# License
```xml
Copyright 2019 skydoves (Jaewoong Eum)
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
```