add isStartRequired, add GroupChannel to synth

1 files changed, 13 insertions, 3 deletions

diff --git a/src/com/jsyn/unitgen/SequentialDataWriter.java b/src/com/jsyn/unitgen/SequentialDataWriter.java
index 5a5febb..cb3bb11 100644
--- a/src/com/jsyn/unitgen/SequentialDataWriter.java
+++ b/src/com/jsyn/unitgen/SequentialDataWriter.java
@@ -4,9 +4,9 @@
  * 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.
@@ -21,7 +21,9 @@ import com.jsyn.ports.UnitInputPort;
 
 /**
  * Base class for writing to a sample.
- * 
+ *
+ * Note that you must call start() on subclasses of this unit because it does not have an output for pulling data.
+ *
  * @author Phil Burk (C) 2009 Mobileer Inc
  */
 public abstract class SequentialDataWriter extends UnitGenerator {
@@ -31,4 +33,12 @@ public abstract class SequentialDataWriter extends UnitGenerator {
     public SequentialDataWriter() {
         addPort(dataQueue = new UnitDataQueuePort("Data"));
     }
+
+    /**
+     * This unit won't do anything unless you start() it.
+     */
+    @Override
+    public boolean isStartRequired() {
+        return true;
+    }
 }