SeqTask: don't hold on to taks list longer than necessary

Author: cpettitt-linkedin

src/com/linkedin/parseq/SeqTask.java

@@ -20,8 +20,6 @@
 import com.linkedin.parseq.promise.Promise;
 import com.linkedin.parseq.promise.Promises;
 import com.linkedin.parseq.promise.SettablePromise;
-import com.linkedin.parseq.trace.ShallowTrace;
-import com.linkedin.parseq.trace.ShallowTraceBuilder;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -30,15 +28,15 @@
 /**
  * A {@link Task} that will run the constructor-supplied tasks one after the other.
  * <p/>
- * Use {@link Tasks#seq(Iterable)} or {@link Tasks#seq(Task[])} to create
+ * Use {@link Tasks#seq(Iterable)} or {@link Tasks#seq(java.lang.Iterable)} to create
  * instances of this class.
  *
  * @author Chris Pettitt ([email protected])
  * @author Chi Chan ([email protected])
  */
 /* package private */ class SeqTask<T> extends SystemHiddenTask<T>
 {
-  private final List<Task<?>> _tasks;
+  private volatile List<Task<?>> _tasks;
 
   public SeqTask(final String name, final Iterable<? extends Task<?>> tasks)
   {
@@ -54,7 +52,6 @@ public SeqTask(final String name, final Iterable<? extends Task<?>> tasks)
       throw new IllegalArgumentException("No tasks to sequence!");
     }
 
-
     _tasks = Collections.unmodifiableList(taskList);
   }
 
@@ -77,6 +74,9 @@ protected Promise<? extends T> run(final Context context) throws Exception
     final Task<T> typedPrevTask = (Task<T>)prevTask;
     Promises.propagateResult(typedPrevTask, result);
     context.run(_tasks.get(0));
+
+    _tasks = null;
+
     return result;
   }
 }