content: /*
   * Copyright (C) 2011 The Android Open Source Project
   *
   * 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 android.filterfw.core;
  
  import android.filterfw.core.Filter;
  import android.filterfw.core.RoundRobinScheduler;
  import android.util.Log;
  
  import java.util.HashMap;
  
  /**
   * This OneShotScheduler only schedules source filters at most once. All other
   * filters will be scheduled, and possibly repeatedly, until there is no filter
   * that can be scheduled.
   *
   * @hide
   */
  public class OneShotScheduler extends RoundRobinScheduler {
      private HashMap <String, Integer> scheduled;
  
      private final boolean mLogVerbose;
      private static final String TAG = "OneShotScheduler";
  
      public OneShotScheduler(FilterGraph graph) {
          super(graph);
          scheduled = new HashMap<String, Integer>();
          mLogVerbose = Log.isLoggable(TAG, Log.VERBOSE);
      }
  
      @Override
      public void reset() {
          super.reset();
          scheduled.clear();
      }
  
      @Override
      public Filter scheduleNextNode() {
          Filter first = null;
          // return the first filter that is not scheduled before.
          while (true) {
              Filter filter = super.scheduleNextNode();
              if (filter == null) {
                  if (mLogVerbose) Log.v(TAG, "No filters available to run.");
                  return null;
              }
              if (!scheduled.containsKey(filter.getName())) {
                  if (filter.getNumberOfConnectedInputs() == 0)
                      scheduled.put(filter.getName(),1);
                  if (mLogVerbose) Log.v(TAG, "Scheduling filter \"" + filter.getName() + "\" of type " + filter.getFilterClassName());
                  return filter;
              }
              // if loop back, nothing available
              if (first == filter) {
                  break;
              }
              // save the first scheduled one
              if (first == null) first = filter;
          }
          if (mLogVerbose) Log.v(TAG, "One pass through graph completed.");
          return null;
      }
  }
  