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client: Add example code to ObservableUtilities

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This commit is contained in:
Andras Slemmer 2016-09-20 10:23:46 +01:00
parent cdf54151f7
commit f6d4d91f36
1 changed files with 46 additions and 22 deletions
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68
client/src/main/kotlin/com/r3corda/client/fxutils/ObservableUtilities.kt
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@ -1,21 +1,38 @@
package com.r3corda.client.fxutils
import com.r3corda.contracts.asset.Cash
import com.r3corda.core.contracts.StateAndRef
import javafx.beans.binding.Bindings
import javafx.beans.property.ReadOnlyObjectWrapper
import javafx.beans.property.SimpleObjectProperty
import javafx.beans.value.ObservableValue
import javafx.collections.ObservableList
import javafx.collections.transformation.FilteredList
import kotlinx.support.jdk8.collections.stream
import org.fxmisc.easybind.EasyBind
import java.util.function.Predicate
import java.util.stream.Collector
/**
* Here follows utility extension functions that help reduce the visual load when developing RX code. Each function should
* have a short accompanying example code.
*/
/**
* val person: ObservableValue<Person> = (..)
* val personName: ObservableValue<String> = person.map { it.name }
*/
fun <A, B> ObservableValue<out A>.map(function: (A) -> B): ObservableValue<B> = EasyBind.map(this, function)
/**
* val dogs: ObservableList<Dog> = (..)
* val dogOwners: ObservableList<Person> = dogs.map { it.owner }
*/
fun <A, B> ObservableList<out A>.map(function: (A) -> B): ObservableList<B> = EasyBind.map(this, function)
/**
* val aliceHeight: ObservableValue<Long> = (..)
* val bobHeight: ObservableValue<Long> = (..)
* fun sumHeight(a: Long, b: Long): Long { .. }
*
* val aliceBobSumHeight = ::sumHeight.lift(aliceHeight, bobHeight)
* val aliceHeightPlus2 = ::sumHeight.lift(aliceHeight, 2L.lift())
*/
fun <A> A.lift(): ObservableValue<A> = ReadOnlyObjectWrapper(this)
fun <A, R> ((A) -> R).lift(
arg0: ObservableValue<A>
@ -36,11 +53,24 @@ fun <A, B, C, D, R> ((A, B, C, D) -> R).lift(
arg3: ObservableValue<D>
): ObservableValue<R> = EasyBind.combine(arg0, arg1, arg2, arg3, this)
/**
* data class Person(val height: ObservableValue<Long>)
* val person: ObservableValue<Person> = (..)
* val personHeight: ObservableValue<Long> = person.bind { it.height }
*/
fun <A, B> ObservableValue<out A>.bind(function: (A) -> ObservableValue<out B>): ObservableValue<out B> =
// We cast here to enforce variance, flatMap should be covariant
@Suppress("UNCHECKED_CAST")
EasyBind.monadic(this).flatMap(function as (A) -> ObservableValue<B>)
/**
* enum class FilterCriterion { HEIGHT, NAME }
* val filterCriterion: ObservableValue<FilterCriterion> = (..)
* val people: ObservableList<Person> = (..)
* fun filterFunction(filterCriterion: FilterCriterion): (Person) -> Boolean { .. }
*
* val filteredPeople: ObservableList<Person> = people.filter(filterCriterion.map(filterFunction))
*/
fun <A> ObservableList<out A>.filter(predicate: ObservableValue<out (A) -> Boolean>): ObservableList<out A> {
// We cast here to enforce variance, FilteredList should be covariant
@Suppress("UNCHECKED_CAST")
@ -51,6 +81,11 @@ fun <A> ObservableList<out A>.filter(predicate: ObservableValue<out (A) -> Boole
}
}
/**
* val people: ObservableList<Person> = (..)
* val concatenatedNames = people.fold("", { names, person -> names + person.name })
* val concatenatedNames2 = people.map(Person::name).fold("", String::plus)
*/
fun <A, B> ObservableList<out A>.fold(initial: B, folderFunction: (B, A) -> B): ObservableValue<B> {
return Bindings.createObjectBinding({
var current = initial
@ -61,20 +96,9 @@ fun <A, B> ObservableList<out A>.fold(initial: B, folderFunction: (B, A) -> B):
}, arrayOf(this))
}
fun <A> ObservableList<out ObservableValue<out A>>.flatten(): ObservableList<out A> {
return FlattenedList(this)
}
fun sum(a: Int, b: Int): Int = a + b
fun main(args: Array<String>) {
val a = SimpleObjectProperty(0)
val b = SimpleObjectProperty(0)
::sum.lift(a, b).addListener { observableValue, i0, i1 ->
println(i1)
}
a.set(2)
b.set(4)
}
/**
* data class Person(val height: ObservableValue<Long>)
* val people: ObservableList<Person> = (..)
* val heights: ObservableList<Long> = people.map(Person::height).flatten()
*/
fun <A> ObservableList<out ObservableValue<out A>>.flatten(): ObservableList<out A> = FlattenedList(this)