X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fws2%2Factions%2Fapi%2FTaskEventListener.java;h=b0bb4b63fe5373078c1b2eab4e49113726b5a153;hb=4df015be529a2e1b12c6b82b061798e186cc154b;hp=f48272a1c350a5f0391bd0c15473d7cea1695daf;hpb=d19882378d8912834a5e196a30f78491cb1e621a;p=jalview.git

diff --git a/src/jalview/ws2/actions/api/TaskEventListener.java b/src/jalview/ws2/actions/api/TaskEventListener.java
index f48272a..b0bb4b6 100644
--- a/src/jalview/ws2/actions/api/TaskEventListener.java
+++ b/src/jalview/ws2/actions/api/TaskEventListener.java
@@ -2,6 +2,7 @@ package jalview.ws2.actions.api;
 
 import java.util.List;
 
+import jalview.bin.Console;
 import jalview.ws2.api.JobStatus;
 import jalview.ws2.api.WebServiceJobHandle;
 
@@ -29,7 +30,7 @@ public interface TaskEventListener<T>
    * @param subJobs
    *          list of sub-jobs for this run
    */
-  void taskStarted(TaskI<T> source, List<? extends JobI> subJobs);
+  default void taskStarted(TaskI<T> source, List<? extends JobI> subJobs) {};
 
   /**
    * Invoked when the global task status has changed.
@@ -39,7 +40,7 @@ public interface TaskEventListener<T>
    * @param status
    *          new task status
    */
-  void taskStatusChanged(TaskI<T> source, JobStatus status);
+  default void taskStatusChanged(TaskI<T> source, JobStatus status) {};
 
   /**
    * Invoked when the task has completed. If the task completed with a result,
@@ -51,7 +52,7 @@ public interface TaskEventListener<T>
    * @param result
    *          computation result or null if result not present
    */
-  void taskCompleted(TaskI<T> source, T result);
+  default void taskCompleted(TaskI<T> source, T result) {};
 
   /**
    * Invoked when an unhandled exception has occurred during task execution.
@@ -61,8 +62,7 @@ public interface TaskEventListener<T>
    * @param e
    *          exception
    */
-  void taskException(TaskI<T> source, Exception e);
-
+  default void taskException(TaskI<T> source, Exception e) {};
 
   /**
    * Invoked when the status of a sub-job has changed.
@@ -74,7 +74,7 @@ public interface TaskEventListener<T>
    * @param status
    *          new job status
    */
-  void subJobStatusChanged(TaskI<T> source, JobI job, JobStatus status);
+  default void subJobStatusChanged(TaskI<T> source, JobI job, JobStatus status) {};
 
   /**
    * Invoked when a log string of the sub-job has changed.
@@ -86,7 +86,7 @@ public interface TaskEventListener<T>
    * @param log
    *          new log string
    */
-  void subJobLogChanged(TaskI<T> source, JobI job, String log);
+  default void subJobLogChanged(TaskI<T> source, JobI job, String log) {};
 
   /**
    * Invoked when an error log string of the sub-job has changed.
@@ -98,5 +98,56 @@ public interface TaskEventListener<T>
    * @param log
    *          new log string
    */
-  void subJobErrorLogChanged(TaskI<T> source, JobI job, String log);
+  default void subJobErrorLogChanged(TaskI<T> source, JobI job, String log) {};
+
+  @SuppressWarnings("rawtypes")
+  static final TaskEventListener NULL_LISTENER = new TaskEventListener()
+  {
+    @Override
+    public void taskStarted(TaskI source, List subJobs)
+    {
+      Console.info("task started with " + subJobs.size() + " jobs");
+    }
+
+    @Override
+    public void taskStatusChanged(TaskI source, JobStatus status)
+    {
+      Console.info("task status " + status);
+    }
+
+    @Override
+    public void taskCompleted(TaskI source, Object result)
+    {
+      Console.info("task completed");
+    }
+
+    @Override
+    public void taskException(TaskI source, Exception e)
+    {
+      Console.info("task failed", e);
+    }
+
+    @Override
+    public void subJobStatusChanged(TaskI source, JobI job,
+            JobStatus status)
+    {
+      Console.info("sub-job " + job.getInternalId() + " status " + status);
+    }
+
+    @Override
+    public void subJobLogChanged(TaskI source, JobI job, String log)
+    {
+    }
+
+    @Override
+    public void subJobErrorLogChanged(TaskI source, JobI job, String log)
+    {
+    }
+  };
+
+  @SuppressWarnings("unchecked")
+  static <T> TaskEventListener<T> nullListener()
+  {
+    return (TaskEventListener<T>) NULL_LISTENER;
+  }
 }