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Work on #403, incorporate review changes

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This commit is contained in:
Narendra Pathai
2016-08-04 18:10:50 +05:30
parent e7be94d2e4
commit 76970633b8
5 changed files with 100 additions and 54 deletions
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5
promise/README.md
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@@ -3,10 +3,11 @@ layout: pattern
title: Promise
folder: promise
permalink: /patterns/promise/
categories: Structural
categories: Concurrency
tags:
- Java
- Concurrency
- Functional
- Reactive
- Difficulty-Intermediate
---

46
promise/etc/promise.ucls
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@@ -74,38 +74,38 @@
<operations public="true" package="true" protected="true" private="false" static="true"/>
</display>
</class>
<realization id="9">
<end type="SOURCE" refId="3"/>
<end type="TARGET" refId="2"/>
</realization>
<dependency id="10">
<end type="SOURCE" refId="8"/>
<end type="TARGET" refId="1"/>
</dependency>
<generalization id="11">
<generalization id="9">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="3"/>
</generalization>
<dependency id="12">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="4"/>
</dependency>
<dependency id="13">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="7"/>
</dependency>
<dependency id="14">
<end type="SOURCE" refId="8"/>
<end type="TARGET" refId="4"/>
</dependency>
<dependency id="15">
<realization id="10">
<end type="SOURCE" refId="3"/>
<end type="TARGET" refId="2"/>
</realization>
<dependency id="11">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="6"/>
</dependency>
<dependency id="16">
<dependency id="12">
<end type="SOURCE" refId="8"/>
<end type="TARGET" refId="1"/>
</dependency>
<dependency id="13">
<end type="SOURCE" refId="8"/>
<end type="TARGET" refId="4"/>
</dependency>
<dependency id="14">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="7"/>
</dependency>
<dependency id="15">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="5"/>
</dependency>
<dependency id="16">
<end type="SOURCE" refId="1"/>
<end type="TARGET" refId="4"/>
</dependency>
<classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
sort-features="false" accessors="true" visibility="true">
<attributes public="true" package="true" protected="true" private="true" static="true"/>

73
promise/src/main/java/com/iluwatar/promise/App.java
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@@ -22,6 +22,15 @@
*/
package com.iluwatar.promise;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
@@ -44,6 +53,8 @@ import java.util.concurrent.Executors;
* <li> Prevents callback hell and provides callback aggregation
* </ul>
*
* <p>
*
* @see CompletableFuture
*/
public class App {
@@ -68,23 +79,57 @@ public class App {
private static void promiseUsage(Executor executor)
throws InterruptedException, ExecutionException {
Promise<Integer> consumedPromise = new Promise<>();
consumedPromise.fulfillInAsync(() -> {
Thread.sleep(1000);
return 10;
}, executor).then(value -> {
System.out.println("Consumed int value: " + value);
String urlString = "https://raw.githubusercontent.com/iluwatar/java-design-patterns/Promise/promise/README.md";
Promise<Integer> lineCountPromise = new Promise<String>().fulfillInAsync(() -> {
return downloadFile(urlString);
}, executor).then(fileLocation -> {
return countLines(fileLocation);
});
Promise<String> transformedPromise = new Promise<>();
transformedPromise.fulfillInAsync(() -> {
Thread.sleep(1000);
return "10";
}, executor).then(value -> { return Integer.parseInt(value); }).then(value -> {
System.out.println("Consumed transformed int value: " + value);
Promise<Map<Character, Integer>> charFrequencyPromise = new Promise<String>().fulfillInAsync(() -> {
return String.valueOf(downloadFile(urlString));
}, executor).then(fileLocation -> {
return characterFrequency(fileLocation);
});
consumedPromise.get();
transformedPromise.get();
lineCountPromise.get();
System.out.println("Line count is: " + lineCountPromise.get());
charFrequencyPromise.get();
System.out.println("Char frequency is: " + charFrequencyPromise.get());
}
private static Map<Character, Integer> characterFrequency(String fileLocation) {
// TODO Auto-generated method stub
return null;
}
private static Integer countLines(String fileLocation) {
int lineCount = 0;
try (Reader reader = new FileReader(fileLocation);
BufferedReader bufferedReader = new BufferedReader(reader);) {
for (String line; (line = bufferedReader.readLine()) != null; ) {
lineCount++;
}
} catch (IOException ex) {
ex.printStackTrace();
}
return lineCount;
}
private static String downloadFile(String urlString) throws InterruptedException, IOException {
URL url = new URL(urlString);
File file = File.createTempFile("promise_pattern", null);
try (Reader reader = new InputStreamReader(url.openStream());
BufferedReader bufferedReader = new BufferedReader(reader);
FileWriter writer = new FileWriter(file)) {
for (String line; (line = bufferedReader.readLine()) != null; ) {
writer.write(line);
writer.write("\n");
}
} catch (IOException ex) {
ex.printStackTrace();
}
System.out.println("File downloaded at: " + file.getAbsolutePath());
return file.getAbsolutePath();
}
}

16
promise/src/main/java/com/iluwatar/promise/Promise.java
View File

@@ -120,11 +120,11 @@ public class Promise<T> extends PromiseSupport<T> {
*/
private class ConsumeAction implements Runnable {
private Promise<T> src;
private Promise<Void> dest;
private Consumer<? super T> action;
private final Promise<T> src;
private final Promise<Void> dest;
private final Consumer<? super T> action;
ConsumeAction(Promise<T> src, Promise<Void> dest, Consumer<? super T> action) {
private ConsumeAction(Promise<T> src, Promise<Void> dest, Consumer<? super T> action) {
this.src = src;
this.dest = dest;
this.action = action;
@@ -147,11 +147,11 @@ public class Promise<T> extends PromiseSupport<T> {
*/
private class TransformAction<V> implements Runnable {
private Promise<T> src;
private Promise<V> dest;
private Function<? super T, V> func;
private final Promise<T> src;
private final Promise<V> dest;
private final Function<? super T, V> func;
TransformAction(Promise<T> src, Promise<V> dest, Function<? super T, V> func) {
private TransformAction(Promise<T> src, Promise<V> dest, Function<? super T, V> func) {
this.src = src;
this.dest = dest;
this.func = func;

14
promise/src/main/java/com/iluwatar/promise/PromiseSupport.java
View File

@@ -33,15 +33,15 @@ import java.util.concurrent.TimeoutException;
*/
class PromiseSupport<T> implements Future<T> {
static final int RUNNING = 1;
static final int FAILED = 2;
static final int COMPLETED = 3;
private static final int RUNNING = 1;
private static final int FAILED = 2;
private static final int COMPLETED = 3;
final Object lock;
private final Object lock;
volatile int state = RUNNING;
T value;
Exception exception;
private volatile int state = RUNNING;
private T value;
private Exception exception;
PromiseSupport() {
this.lock = new Object();