1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 18package android.filterfw.core; 19 20import android.filterfw.core.Filter; 21import android.filterfw.core.RoundRobinScheduler; 22import android.util.Log; 23 24import java.util.HashMap; 25 26/** 27 * This OneShotScheduler only schedules source filters at most once. All other 28 * filters will be scheduled, and possibly repeatedly, until there is no filter 29 * that can be scheduled. 30 * 31 * @hide 32 */ 33public class OneShotScheduler extends RoundRobinScheduler { 34 private HashMap <String, Integer> scheduled; 35 36 private final boolean mLogVerbose; 37 private static final String TAG = "OneShotScheduler"; 38 39 public OneShotScheduler(FilterGraph graph) { 40 super(graph); 41 scheduled = new HashMap<String, Integer>(); 42 mLogVerbose = Log.isLoggable(TAG, Log.VERBOSE); 43 } 44 45 @Override 46 public void reset() { 47 super.reset(); 48 scheduled.clear(); 49 } 50 51 @Override 52 public Filter scheduleNextNode() { 53 Filter first = null; 54 // return the first filter that is not scheduled before. 55 while (true) { 56 Filter filter = super.scheduleNextNode(); 57 if (filter == null) { 58 if (mLogVerbose) Log.v(TAG, "No filters available to run."); 59 return null; 60 } 61 if (!scheduled.containsKey(filter.getName())) { 62 if (filter.getNumberOfConnectedInputs() == 0) 63 scheduled.put(filter.getName(),1); 64 if (mLogVerbose) Log.v(TAG, "Scheduling filter \"" + filter.getName() + "\" of type " + filter.getFilterClassName()); 65 return filter; 66 } 67 // if loop back, nothing available 68 if (first == filter) { 69 break; 70 } 71 // save the first scheduled one 72 if (first == null) first = filter; 73 } 74 if (mLogVerbose) Log.v(TAG, "One pass through graph completed."); 75 return null; 76 } 77} 78