Added ThreadPool

.travis.yml

@@ -3,4 +3,8 @@ language: java
 sudo: false
 
 notifications:
-  email: false
+  email: false
+
+env:
+  - TEST_DIR=ThreadPool
+script: cd $TEST_DIR && ./gradlew clean check

ThreadPool/build.gradle

@@ -0,0 +1,15 @@
+group 'ru.spbau.dkaznacheev'
+version '1.0-SNAPSHOT'
+
+apply plugin: 'java'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+    compile group: 'org.jetbrains', name: 'annotations', version: '13.0'
+}

ThreadPool/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Fri Mar 09 02:05:00 MSK 2018
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-3.5-rc-2-all.zip

ThreadPool/settings.gradle

@@ -0,0 +1,3 @@
+rootProject.name = 'ThreadPool'
+rootProject.name = 'ThreadPool'
+

ThreadPool/src/main/java/ru/spbau/dkaznacheev/threadpool/LightFuture.java

@@ -0,0 +1,27 @@
+package ru.spbau.dkaznacheev.threadpool;
+
+import java.util.function.Function;
+
+public interface LightFuture<T> {
+
+    /**
+     * Returns whether a computation is completed.
+     * @return whether a computation is completed
+     */
+    boolean isReady();
+
+    /**
+     * Returns the result of the computation, if it is not completed, this method blocks the execution.
+     * @return result of the computation
+     * @throws LightFutureException if an exception occurred during a computation
+     */
+    T get() throws LightFutureException;
+
+    /**
+     * Applies the result of current computation to another and returns another computation's LightFuture.
+     * @param function the function to compute with this LightFuture's result
+     * @param <U> type that the function returns
+     * @return the result of the function
+     */
+    <U> LightFuture<U> thenApply(Function<T, U> function);
+}

ThreadPool/src/main/java/ru/spbau/dkaznacheev/threadpool/LightFutureException.java

@@ -0,0 +1,7 @@
+package ru.spbau.dkaznacheev.threadpool;
+
+/**
+ * An Exception that is thrown when a computation in ThreadPool throws an Exception.
+ */
+public class LightFutureException extends RuntimeException {
+}

ThreadPool/src/main/java/ru/spbau/dkaznacheev/threadpool/ThreadPool.java

@@ -0,0 +1,21 @@
+package ru.spbau.dkaznacheev.threadpool;
+
+import java.util.function.Supplier;
+
+/**
+ * ThreadPool interface. It is capable of adding tasks to it and shutting down all of current workers.
+ */
+public interface ThreadPool {
+    /**
+     * Adds a task to the pool, returning a LightFuture object.
+     * @param supplier supplier for the computation
+     * @param <T> type of the result
+     * @return LightFuture object that will contain the result of computation
+     */
+    <T> LightFuture<T> addTask(Supplier<T> supplier);
+
+    /**
+     * Shuts down all of its current workers.
+     */
+    void shutdown() throws InterruptedException;
+}