├── .gitignore
├── .idea
├── .name
├── codeStyleSettings.xml
├── compiler.xml
├── copyright
│ └── profiles_settings.xml
├── inspectionProfiles
│ ├── Project_Default.xml
│ └── profiles_settings.xml
├── misc.xml
├── modules.xml
├── vcs.xml
└── workspace.xml
├── README.md
├── build.gradle
├── quasar-kotlin-jetbrains-webinar.iml
└── src
└── main
└── kotlin
└── Main.kt
/.gitignore:
--------------------------------------------------------------------------------
1 | ### Java template
2 | *.class
3 |
4 | # Mobile Tools for Java (J2ME)
5 | .mtj.tmp/
6 |
7 | # Package Files #
8 | *.jar
9 | *.war
10 | *.ear
11 |
12 | # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
13 | hs_err_pid*
14 | ### JetBrains template
15 | # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio
16 |
17 | # *.iml
18 |
19 | ## Directory-based project format:
20 | # .idea/
21 | # if you remove the above rule, at least ignore the following:
22 |
23 | # User-specific stuff:
24 | # .idea/workspace.xml
25 | .idea/tasks.xml
26 | .idea/dictionaries
27 |
28 | # Sensitive or high-churn files:
29 | .idea/dataSources.ids
30 | .idea/dataSources.xml
31 | .idea/sqlDataSources.xml
32 | .idea/dynamic.xml
33 | .idea/uiDesigner.xml
34 |
35 | # Gradle:
36 | .idea/gradle.xml
37 | .idea/libraries
38 |
39 | # Mongo Explorer plugin:
40 | .idea/mongoSettings.xml
41 |
42 | ## File-based project format:
43 | # *.ipr
44 | # *.iws
45 |
46 | ## Plugin-specific files:
47 |
48 | # IntelliJ
49 | /out/
50 |
51 | # mpeltonen/sbt-idea plugin
52 | .idea_modules/
53 |
54 | # JIRA plugin
55 | atlassian-ide-plugin.xml
56 |
57 | # Crashlytics plugin (for Android Studio and IntelliJ)
58 | com_crashlytics_export_strings.xml
59 | crashlytics.properties
60 | crashlytics-build.properties
61 | ### Gradle template
62 | .gradle
63 | build/
64 |
65 | # Ignore Gradle GUI config
66 | gradle-app.setting
67 |
68 | # Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
69 | !gradle-wrapper.jar
70 |
71 | # Created by .ignore support plugin (hsz.mobi)
72 |
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/.idea/.name:
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1420 | 1.7
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1445 | Gradle: co.paralleluniverse:quasar-actors:0.7.0
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/README.md:
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1 | ```
2 | gradle
3 | ```
4 |
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/build.gradle:
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1 | buildscript {
2 | repositories {
3 | mavenCentral()
4 | }
5 | dependencies {
6 | classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.0.1-2"
7 | }
8 | }
9 |
10 | apply plugin: 'java'
11 | apply plugin: 'kotlin'
12 | apply plugin: 'application'
13 |
14 | version = '0.1.0-SNAPSHOT'
15 | status = 'integration'
16 |
17 | ext.classifier = ':jdk8'
18 | sourceCompatibility = 1.8
19 | targetCompatibility = 1.8
20 |
21 | ext.quasarVer = '0.7.5-SNAPSHOT'
22 | ext.logbackVer = '1.1.3'
23 | ext.slf4jVer = '1.7.21'
24 |
25 | ext.kotlinVer = '1.0.1-2'
26 |
27 | [compileJava, compileTestJava]*.options*.encoding = 'UTF-8'
28 |
29 | configurations {
30 | quasar
31 | }
32 |
33 | configurations.all {
34 | resolutionStrategy {
35 | failOnVersionConflict()
36 |
37 | force "org.slf4j:slf4j-api:$slf4jVer"
38 | }
39 | }
40 |
41 | repositories {
42 | // mavenLocal()
43 | mavenCentral()
44 | maven { url "https://oss.sonatype.org/content/repositories/releases" }
45 | maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }
46 | // maven { url 'https://maven.java.net/content/repositories/snapshots' }
47 | }
48 |
49 | dependencies {
50 | compile "co.paralleluniverse:quasar-core:${quasarVer}${classifier}"
51 | compile "co.paralleluniverse:quasar-kotlin:${quasarVer}"
52 |
53 | compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVer"
54 | compile "org.jetbrains.kotlin:kotlin-reflect:$kotlinVer"
55 |
56 | quasar "co.paralleluniverse:quasar-core:${quasarVer}${classifier}@jar"
57 |
58 | runtime "ch.qos.logback:logback-classic:${logbackVer}"
59 | }
60 |
61 | mainClassName = 'MainKt'
62 |
63 | applicationDefaultJvmArgs = [
64 | // "-Dco.paralleluniverse.fibers.verifyInstrumentation=true",
65 | "-Dco.paralleluniverse.fibers.detectRunawayFibers=false",
66 | "-javaagent:${configurations.quasar.singleFile}" // =v, =d
67 | ]
68 |
69 | run {
70 | standardInput = System.in
71 | }
72 |
73 | defaultTasks 'run'
74 |
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/quasar-kotlin-jetbrains-webinar.iml:
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/src/main/kotlin/Main.kt:
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1 | // - Semicolons are optional in Kotlin.
2 | // - Kotlin support _import bindings_.
3 | // - "import" can be used for all sorts of inputs (package, class, object etc.).
4 |
5 | import java.util.function.*
6 |
7 | import com.google.common.collect.EvictingQueue
8 |
9 | import co.paralleluniverse.strands.*
10 | import java.util.concurrent.CompletableFuture
11 | import java.util.concurrent.ConcurrentHashMap
12 | import java.util.concurrent.ThreadLocalRandom
13 |
14 | import kotlin.concurrent.thread
15 |
16 | /**
17 | * Stock
18 | */
19 | // - Kotlin _primary constructor_ is part of the class header and can specify `val` or `var` to
20 | // create corresponding mutable or immutable _properties_ resp.: no boilerplate assignments are
21 | // necessary.
22 | class Stock(val name: String) {
23 |
24 | // - Kotlin supports singletons directly as _literal objects_ and _companion objects_ are a special case
25 | // that can be referred through the enclosing class' identifier.
26 | // - Singleton objects are full-blown objects: they can inherit, implement and define properties and methods.
27 | companion object {
28 |
29 | // - Kotlin is strongly types but has extensive type inference,
30 | // although explicit typing for signatures is required.
31 | private val HISTORY_WINDOW_SIZE = 10
32 |
33 | // - There's no "new" keyword in Kotlin, constructors are called simply through the class name.
34 | val default = Stock("whatever")
35 |
36 | /**
37 | * Finds a stock by name. The current example implementation just constructs and caches Stock objects.
38 | */
39 | // - Companion object methods and properties can be used as an equivalent of Java's _static_.
40 | // - Methods can be defined by an expression, in this case the return type is optional.
41 | // - Method parameters can also have default values.
42 | private fun find(name: String = "goog") =
43 | // - Kotlin supports higher-order functions.
44 | // - If the last parameter is a function, a DSL-like block-based syntax can be used.
45 | // - A _lambda_, or _function literal_, has the form `{ (param1[:Type1], ...) -> BODY }` and
46 | // if there is only a single parameter the `{ BODY }` form can be used and the parameter
47 | // can be referred to as `it`.
48 | cache.getOrPut(name) {
49 | Stock(name)
50 | }
51 | private val cache = ConcurrentHashMap()
52 |
53 | // - We'll simulate a slow system with threads that will wait up to 3 seconds to answer our inquiry
54 | private val MAX_WAIT_MILLIS: Long = 3000
55 | private fun slowAsyncVal(s: I, f: (I) -> O): CompletableFuture {
56 | val ret = CompletableFuture()
57 | thread {
58 | Strand.sleep(ThreadLocalRandom.current().nextLong(0, MAX_WAIT_MILLIS))
59 | ret.complete(f(s))
60 | }
61 | return ret
62 | }
63 | fun findAsync(s: String) = slowAsyncVal(s) { Stock.find(it) ?: Stock.default }
64 | fun avgAsync(s: Stock) = slowAsyncVal(s) {
65 | it.avg()
66 | }
67 | fun currentAsync(s: Stock) = slowAsyncVal(s) { it.current() }
68 | fun adviceAsync(s: Stock) = slowAsyncVal(s) { it.advice() }
69 | }
70 |
71 | /**
72 | * Sliding window for historical data
73 | */
74 | private val hist = EvictingQueue.create(HISTORY_WINDOW_SIZE)
75 |
76 | // - Kotlin classes can have _initialization blocks_.
77 | init {
78 | // - Kotlin supports _dynamic ranges_.
79 | for(i in 0..HISTORY_WINDOW_SIZE)
80 | hist.offer(Value(newVal().num))
81 | }
82 |
83 | /**
84 | * Generates a new stock value
85 | */
86 | // - Kotlin has _`public`_, _`private`_, _`protected`_ and _`internal`_ (default) visibility.
87 | private fun newVal(): Value =
88 | Value (
89 | // - Many Kotlin constructs, like "if", can be used both as statements and as expressions.
90 | if (hist.isEmpty())
91 | ThreadLocalRandom.current().nextDouble()
92 | else {
93 | // - Locals can be mutable or immutable too.
94 | val DEVIATION = 0.25
95 | val last = hist.last().num
96 | last + (last * ThreadLocalRandom.current().nextDouble(-DEVIATION, +DEVIATION))
97 | }
98 | )
99 |
100 | /**
101 | * Calculates the current stock value
102 | */
103 | private fun current(): Value {
104 | hist.offer(newVal())
105 |
106 | // - `return` is mandatory if the method is defined as a block
107 | return hist.last()
108 | }
109 |
110 | /**
111 | * Calculates the current stock advice
112 | */
113 | private fun advice(): Advice =
114 | Advice.values()[ThreadLocalRandom.current().nextInt(0, Advice.values().size)]
115 |
116 | /**
117 | * Returns the historical average
118 | */
119 | fun avg() =
120 | // - What _is_ the average? It is the division by its size of
121 | // (the sum of
122 | // (the map
123 | // of the historical data
124 | // on its numerical value
125 | // )
126 | // )
127 | hist.map { it.num }.sum() / hist.size
128 | }
129 |
130 | /**
131 | * Stock value
132 | */
133 | // - For _data classes_ Kotlin will generate "toString", "equals", "hashCode" and a nice "copy" method with
134 | // optional parameters to replace some of the properties during the copy.
135 | data class Value(val num: Double)
136 |
137 | /**
138 | * Stock Advice
139 | */
140 | // - Kotlin _enum literals_ are _literal object instances_ of the _enum class_.
141 | enum class Advice {
142 | BUY, SELL, KEEP
143 | }
144 |
145 | // - _Functional monadic async_: let's _define_ a representation of our program as a "special" equation
146 | // both marked as performing async actions and compositions and allowed to used it.
147 | // - Monadic programs are essentially _async_ and _lazy_ and usually implemented in libraries so
148 | // they are extremely difficult to debug with regular tools.
149 |
150 | // - Monads creep into signatures because they are meant to "mark" programs, they are _infectious_.
151 | fun main(args: Array) {
152 |
153 | print("Insert the stock name: ")
154 |
155 | val sName = readLine() ?: "goog"
156 |
157 | println("Defining and submitting the monadic async program...")
158 |
159 | // - Let's use Java 8's `CompletableFuture` to model our monadic async program.
160 | Stock.findAsync(sName)
161 | // - Monadic `flatMap` or `bind`
162 | .thenComposeAsync(Function {
163 | // - We'll create 3 "concurrent" async monads now.
164 | val calcAvg = Stock.avgAsync(it)
165 | val calcNext = Stock.currentAsync(it)
166 | val calcAdvice = Stock.adviceAsync(it)
167 | // - We'll compose them with `allOf` and then use `thenApply` or monadic `map` to print the results.
168 | CompletableFuture.allOf(calcAvg, calcNext, calcAdvice).thenApply {
169 | println("The historical average is: ${calcAvg.join()}")
170 | println("The current value is: ${calcNext.join()}")
171 | println("The current advice is: ${calcAdvice.join()}")
172 | }
173 | })
174 |
175 | // 3) No need for run, will start immediately. But let's say we have submitted.
176 | println("...Submitted!")
177 | }
178 |
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