[APGAS] added finish expression construct

apgas/src/apgas/Constructs.java

@@ -13,6 +13,7 @@
 
 import java.io.Serializable;
 import java.util.List;
+import java.util.concurrent.Callable;
 
 import apgas.impl.SerializableRunnable;
 
@@ -31,7 +32,7 @@ private Constructs() {
    * Runs {@code f} then waits for all tasks transitively spawned by {@code f}
    * to complete.
    * <p>
-   * If {@code f} or the transitively tasks spawned by {@code f} have uncaught
+   * If {@code f} or the tasks transitively spawned by {@code f} have uncaught
    * exceptions then {@code finish(f)} then throws a {@link MultipleException}
    * that collects these uncaught exceptions.
    *
@@ -44,6 +45,24 @@ public static void finish(Job f) {
     GlobalRuntime.getRuntime().finish(f);
   }
 
+  /**
+   * Evaluates {@code f}, waits for all the tasks transitively spawned by
+   * {@code f}, and returns the result.
+   * <p>
+   * If {@code f} or the tasks transitively spawned by {@code f} have uncaught
+   * exceptions then {@code finish(F)} then throws a {@link MultipleException}
+   * that collects these uncaught exceptions.
+   *
+   * @param <T>
+   *          the type of the result
+   * @param f
+   *          the function to run
+   * @return the result of the evaluation
+   */
+  public static <T> T finish(Callable<T> f) {
+    return GlobalRuntime.getRuntime().finish(f);
+  }
+
   /**
    * Submits a new local task to the global runtime with body {@code f} and
    * returns immediately.

apgas/src/apgas/GlobalRuntime.java

@@ -13,6 +13,7 @@
 
 import java.io.Serializable;
 import java.util.List;
+import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.function.Consumer;
 
@@ -98,7 +99,7 @@ public static GlobalRuntime getRuntime() {
    * Runs {@code f} then waits for all tasks transitively spawned by {@code f}
    * to complete.
    * <p>
-   * If {@code f} or the transitively tasks spawned by {@code f} have uncaught
+   * If {@code f} or the tasks transitively spawned by {@code f} have uncaught
    * exceptions then {@code finish(F)} then throws a {@link MultipleException}
    * that collects these uncaught exceptions.
    *
@@ -109,6 +110,22 @@ public static GlobalRuntime getRuntime() {
    */
   protected abstract void finish(Job f);
 
+  /**
+   * Evaluates {@code f}, waits for all the tasks transitively spawned by
+   * {@code f}, and returns the result.
+   * <p>
+   * If {@code f} or the tasks transitively spawned by {@code f} have uncaught
+   * exceptions then {@code finish(F)} then throws a {@link MultipleException}
+   * that collects these uncaught exceptions.
+   *
+   * @param <T>
+   *          the type of the result
+   * @param f
+   *          the function to run
+   * @return the result of the evaluation
+   */
+  protected abstract <T> T finish(Callable<T> f);
+
   /**
    * Submits a new local task to the global runtime with body {@code f} and
    * returns immediately.

apgas/src/apgas/impl/GlobalRuntimeImpl.java

@@ -20,6 +20,7 @@
 import java.util.List;
 import java.util.SortedSet;
 import java.util.TreeSet;
+import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ForkJoinPool;
 import java.util.concurrent.ForkJoinTask;
@@ -34,6 +35,7 @@
 import apgas.Place;
 import apgas.SerializableCallable;
 import apgas.SerializableJob;
+import apgas.util.Cell;
 import apgas.util.GlobalID;
 
 import com.hazelcast.core.IMap;
@@ -366,6 +368,13 @@ public void finish(Job f) {
     }
   }
 
+  @Override
+  public <T> T finish(Callable<T> f) {
+    final Cell<T> cell = new Cell<T>();
+    finish(() -> cell.set(f.call()));
+    return cell.get();
+  }
+
   @Override
   public void async(Job f) {
     final Worker worker = currentWorker();