RxComprehensions
RxComprehensions is a library to reduce boilerplate and simplify your Observable chains.
Rationale
As your code starts getting more and more functional, you find that you have to chain multiple Observable by means of flatMap(), concatMap(), or switchMap(). This causes indentation levels to go quite high, and would often require that you split the code in several methods just to keep it readable.
Observable<String> getUserFriends =
profileClicks()
.flatMap {
position ->
getUserFromProfile(position)
.flatMap {
user ->
requestFriendListForUser(position, user.id)
.flatMap {
friends ->
storeUserAndFriends(user, friends)
.flatMap {
result ->
toUserDisplayString(position, user, friends, result)
}
}
}
}
Comprehensions are a language feature that allow you to define such a chain in a way where every observable is a function at topmost indentation, yet still contains all the parameters received in the previous functions.
Usage
Map comprehensions
RxComprehensions contains static methods doFlatMap() for flatMap(), doConcatMap() for concatMap(), doSwitchMap() for switchMap(). Each takes from 1 to 9 FuncN each with an increasing number of parameters, and returns an Observable of the type of the return of the last function.
Observable<String> getUserFriends =
// chained with flatMap()
RxComprehensions.doFlatMap(
() -> profileClicks(),
position -> getUserFromProfile(position),
position, user -> requestFriendListForUser(position, user.id),
position, user, friends -> storeUserAndFriends(user, friends),
position, user, friends, result -> toUserDisplayString(position, user, friends, result)
);
Compose comprehensions
RxComprehensions contains static methods doCompose() for compose(). Each takes from 1 to 9 Transformer<T, U> (RxJava 1.X) or ObservableTransformer<T, U> (RxJava 2.X), and returns an Observable of the type of the return of the last one.
Observable<List<Siblings>> getRelatives =
// chained with compose()
RxComprehensions.doCompose(
() -> requestRelative("12345"),
validate(),
assureThreads(Schedulers.io(), AndroidSchedulers.main()),
respectLifecycle(activity),
toUILayerModel(),
groupSiblings()
);
Observable<RelativeDto> requestRelative(String id) {
/* ... */
}
ObservableTransformer<RelativeDto, RelativeDto> validate() {
/* ... */
}
ObservableTransformer<RelativeDto, RelativeDto> assureThreads(Scheduler in, Scheduler out) {
/* ... */
}
ObservableTransformer<RelativeDto, RelativeDto> respectLifecycle(Activity activity) {
/* ... */
}
ObservableTransformer<RelativeDto, Relative> toUILayerModel() {
/* ... */
}
ObservableTransformer<Relative, List<Siblings>> groupSiblings() {
/* ... */
}
Distribution
RxJava 1.X
Add as a dependency to your build.gradle
repositories {
...
maven {
url "https://jitpack.io"
}
...
}
dependencies {
...
compile 'com.github.pakoito.RxComprehensions:rxcomprehensions:1.3.0'
...
}
or to your pom.xml
<repositories>
<repository>
<id>jitpack.io</id>
<url>https://jitpack.io</url>
</repository> </repositories> <dependency>
<groupId>com.github.pakoito.RxComprehensions</groupId>
<artifactId>rxcomprehensions</artifactId>
<version>1.3.0</version> </dependency>RxJava 2.X
Add as a dependency to your build.gradle
repositories {
...
maven {
url "https://jitpack.io"
}
...
}
dependencies {
...
compile 'com.github.pakoito.RxComprehensions:rxcomprehensions2:1.3.0'
...
}
or to your pom.xml
<repositories>
<repository>
<id>jitpack.io</id>
<url>https://jitpack.io</url>
</repository> </repositories> <dependency>
<groupId>com.github.pakoito.RxComprehensions</groupId>
<artifactId>rxcomprehensions2</artifactId>
<version>1.3.0</version> </dependency>License
Copyright (c) pakoito 2016
The Apache Software License, Version 2.0
See LICENSE.md