ExecutorService Pool Implementation

Author: jonathanaustin

…/taskmaster/pool/TaskMasterPoolUtil.java …/taskmaster/impl/TaskMasterPoolUtil.javataskmaster-core/src/main/java/com/github/bordertech/taskmaster/pool/TaskMasterPoolUtil.java renamed to taskmaster-core/src/main/java/com/github/bordertech/taskmaster/impl/TaskMasterPoolUtil.java taskmaster-core/src/main/java/com/github/bordertech/taskmaster/pool/TaskMasterPoolUtil.java renamed to taskmaster-core/src/main/java/com/github/bordertech/taskmaster/impl/TaskMasterPoolUtil.java

@@ -1,4 +1,4 @@
-package com.github.bordertech.taskmaster.pool;
+package com.github.bordertech.taskmaster.impl;
 
 import com.github.bordertech.config.Config;
 import java.util.HashMap;
@@ -52,7 +52,7 @@ private TaskMasterPoolUtil() {
 	 * @param pool the pool name to create
 	 * @return the executor service
 	 */
-	public static ExecutorService buildPool(final String pool) {
+	private static ExecutorService buildPool(final String pool) {
 		// TODO Logging and performance parameters
 		// http://www.nurkiewicz.com/2014/11/executorservice-10-tips-and-tricks.html
 

taskmaster-core/src/main/java/com/github/bordertech/taskmaster/impl/TaskMasterProviderExecutorService.java

@@ -1,20 +1,10 @@
 package com.github.bordertech.taskmaster.impl;
 
-import com.github.bordertech.config.Config;
 import com.github.bordertech.taskmaster.exception.RejectedTaskException;
 import com.github.bordertech.taskmaster.TaskFuture;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
-import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.SynchronousQueue;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
 import javax.inject.Singleton;
 import com.github.bordertech.taskmaster.TaskMasterProvider;
 
@@ -27,86 +17,27 @@
 @Singleton
 public class TaskMasterProviderExecutorService implements TaskMasterProvider {
 
-	private static final Map<String, ExecutorService> THREAD_POOLS = new HashMap<>();
-
-	private static final String TP_PARAM_PREFIX = "bordertech.taskmaster.pool.";
-
-	private static final String DEFAULT_POOL = Config.getInstance().getString(TP_PARAM_PREFIX + "default", "default");
-
-	private static final int DEFAULT_MAX_THREADS = 20;
-	private static final int DEFAULT_QUEUE_LENGTH = 0;
-
-	static {
-		// Load thread pools
-		String[] pools = Config.getInstance().getStringArray(TP_PARAM_PREFIX + "names");
-		for (String pool : pools) {
-			THREAD_POOLS.put(pool, buildPool(pool));
-		}
-		// Check if default pool needs to be created
-		if (!THREAD_POOLS.containsKey(DEFAULT_POOL)) {
-			THREAD_POOLS.put(DEFAULT_POOL, buildPool(DEFAULT_POOL));
-		}
+	@Override
+	public void shutdown() {
+		shutdownNow();
 	}
 
 	/**
-	 * @param pool the pool name to create
-	 * @return the executor service
+	 * TODO This needs to be put in TaskMaster.
 	 */
-	private static ExecutorService buildPool(final String pool) {
-		// TODO Logging and performance parameters
-		// http://www.nurkiewicz.com/2014/11/executorservice-10-tips-and-tricks.html
-
-		// Get the pool type - defaults to cached
-		String type = Config.getInstance().getString(TP_PARAM_PREFIX + pool + ".type", "cached");
-		switch (type.toLowerCase()) {
-			case "single":
-				return Executors.newSingleThreadExecutor();
-			case "fixed":
-				// Number of fixed threads
-				int max = Config.getInstance().getInt(TP_PARAM_PREFIX + pool + ".max", DEFAULT_MAX_THREADS);
-				if (max < 1) {
-					max = DEFAULT_MAX_THREADS;
-				}
-				// Length of pending queue
-				int queue = Config.getInstance().getInt(TP_PARAM_PREFIX + pool + ".queue", DEFAULT_QUEUE_LENGTH);
-				// Create executable with the appropriate queue type
-				BlockingQueue<Runnable> blkQueue;
-				if (queue < 0) {
-					// Unlimited
-					blkQueue = new LinkedBlockingQueue<>();
-				} else if (queue == 0) {
-					// No queue
-					blkQueue = new SynchronousQueue<>();
-				} else {
-					// Fixed queue length
-					blkQueue = new ArrayBlockingQueue<>(queue);
-				}
-				return new ThreadPoolExecutor(max, max, 0L, TimeUnit.MILLISECONDS, blkQueue);
-			default:
-				// Default - Unlimited Threads and No Queue
-				return Executors.newCachedThreadPool();
-		}
-	}
-
-	@Override
-	public void shutdown() {
-		for (ExecutorService exec : THREAD_POOLS.values()) {
-			exec.shutdown();
-		}
+	public void shutdownNow() {
+		// Provide an immediate shutdown of threads without running the waiting threads.
+		TaskMasterPoolUtil.shutdown();
 	}
 
 	@Override
 	public <T> TaskFuture<T> submit(final Runnable task, final T result) throws RejectedTaskException {
-		return submit(task, result, DEFAULT_POOL);
+		return submit(task, result, TaskMasterPoolUtil.DEFAULT_POOL);
 	}
 
 	@Override
 	public <T> TaskFuture<T> submit(final Runnable task, final T result, final String pool) throws RejectedTaskException {
-		String name = pool == null ? DEFAULT_POOL : pool;
-		ExecutorService exec = THREAD_POOLS.get(name);
-		if (exec == null) {
-			throw new IllegalStateException("Thread pool [" + name + "] has not been defined.");
-		}
+		ExecutorService exec = TaskMasterPoolUtil.getPool(pool);
 		try {
 			Future<T> future = exec.submit(task, result);
 			return new TaskFutureWrapper<>(future);