Change the license to GPL v3 to be compatible with Apache License 2.0.

HMCLAPI/src/main/java/rx/concurrency/Schedulers.java

@@ -0,0 +1,143 @@
+/**
+ * Copyright 2013 Netflix, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package rx.concurrency;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+
+import rx.Scheduler;
+
+/**
+ * Static factory methods for creating Schedulers.
+ */
+public class Schedulers {
+    private static final ScheduledExecutorService COMPUTATION_EXECUTOR = createComputationExecutor();
+    private static final Executor IO_EXECUTOR = createIOExecutor();
+
+    private Schedulers() {
+
+    }
+
+    /**
+     * {@link Scheduler} that executes work immediately on the current thread.
+     * 
+     * @return {@link ImmediateScheduler} instance
+     */
+    public static Scheduler immediate() {
+        return ImmediateScheduler.getInstance();
+    }
+
+    /**
+     * {@link Scheduler} that queues work on the current thread to be executed after the current work completes.
+     * 
+     * @return {@link CurrentThreadScheduler} instance
+     */
+    public static Scheduler currentThread() {
+        return CurrentThreadScheduler.getInstance();
+    }
+
+    /**
+     * {@link Scheduler} that creates a new {@link Thread} for each unit of work.
+     * 
+     * @return {@link NewThreadScheduler} instance
+     */
+    public static Scheduler newThread() {
+        return NewThreadScheduler.getInstance();
+    }
+
+    /**
+     * {@link Scheduler} that queues work on an {@link Executor}.
+     * <p>
+     * Note that this does not support scheduled actions with a delay.
+     * 
+     * @return {@link ExecutorScheduler} instance
+     */
+    public static Scheduler executor(Executor executor) {
+        return new ExecutorScheduler(executor);
+    }
+
+    /**
+     * {@link Scheduler} that queues work on an {@link ScheduledExecutorService}.
+     * 
+     * @return {@link ExecutorScheduler} instance
+     */
+    public static Scheduler executor(ScheduledExecutorService executor) {
+        return new ExecutorScheduler(executor);
+    }
+
+    /**
+     * {@link Scheduler} intended for computational work.
+     * <p>
+     * The implementation is backed by a {@link ScheduledExecutorService} thread-pool sized to the number of CPU cores.
+     * <p>
+     * This can be used for event-loops, processing callbacks and other computational work.
+     * <p>
+     * Do not perform IO-bound work on this scheduler. Use {@link #threadPoolForComputation()} instead.
+     * 
+     * @return {@link ExecutorScheduler} for computation-bound work.
+     */
+    public static Scheduler threadPoolForComputation() {
+        return executor(COMPUTATION_EXECUTOR);
+    }
+
+    /**
+     * {@link Scheduler} intended for IO-bound work.
+     * <p>
+     * The implementation is backed by an {@link Executor} thread-pool that will grow as needed.
+     * <p>
+     * This can be used for asynchronously performing blocking IO.
+     * <p>
+     * Do not perform computational work on this scheduler. Use {@link #threadPoolForComputation()} instead.
+     * 
+     * @return {@link ExecutorScheduler} for IO-bound work.
+     */
+    public static Scheduler threadPoolForIO() {
+        return executor(IO_EXECUTOR);
+    }
+
+    private static ScheduledExecutorService createComputationExecutor() {
+        int cores = Runtime.getRuntime().availableProcessors();
+        return Executors.newScheduledThreadPool(cores, new ThreadFactory() {
+            final AtomicInteger counter = new AtomicInteger();
+
+            @Override
+            public Thread newThread(Runnable r) {
+                Thread t = new Thread(r, "RxComputationThreadPool-" + counter.incrementAndGet());
+                t.setDaemon(true);
+                return t;
+            }
+        });
+    }
+
+    private static Executor createIOExecutor() {
+        Executor result = Executors.newCachedThreadPool(new ThreadFactory() {
+            final AtomicLong counter = new AtomicLong();
+
+            @Override
+            public Thread newThread(Runnable r) {
+                Thread t = new Thread(r, "RxIOThreadPool-" + counter.incrementAndGet());
+                t.setDaemon(true);
+                return t;
+            }
+        });
+
+        return result;
+    }
+}