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.filterpacks.base;
  
  import android.filterfw.core.Filter;
  import android.filterfw.core.FilterContext;
  import android.filterfw.core.Frame;
  import android.filterfw.core.GenerateFieldPort;
  import android.filterfw.core.GenerateFinalPort;
  import android.os.Handler;
  import android.os.Looper;
  
  import java.lang.Runnable;
  
  /**
   * @hide
   */
  public class CallbackFilter extends Filter {
  
      @GenerateFieldPort(name = "listener", hasDefault = true)
      private FilterContext.OnFrameReceivedListener mListener;
  
      @GenerateFieldPort(name = "userData", hasDefault = true)
      private Object mUserData;
  
      @GenerateFinalPort(name = "callUiThread", hasDefault = true)
      private boolean mCallbacksOnUiThread = true;
  
      private Handler mUiThreadHandler;
  
      private class CallbackRunnable implements Runnable {
          private Filter mFilter;
          private Frame mFrame;
          private Object mUserData;
          private FilterContext.OnFrameReceivedListener mListener;
  
          public CallbackRunnable(FilterContext.OnFrameReceivedListener listener, Filter filter, Frame frame, Object userData) {
              mListener = listener;
              mFilter = filter;
              mFrame = frame;
              mUserData = userData;
          }
  
          public void run() {
              mListener.onFrameReceived(mFilter, mFrame, mUserData);
              mFrame.release();
          }
      }
  
      public CallbackFilter(String name) {
          super(name);
      }
  
      @Override
      public void setupPorts() {
          addInputPort("frame");
      }
  
      public void prepare(FilterContext context) {
          if (mCallbacksOnUiThread) {
              mUiThreadHandler = new Handler(Looper.getMainLooper());
          }
      }
  
      public void process(FilterContext context) {
          // Get frame and forward to listener
          final Frame input = pullInput("frame");
          if (mListener != null) {
              if (mCallbacksOnUiThread) {
                  input.retain();
                  CallbackRunnable uiRunnable = new CallbackRunnable(mListener, this, input, mUserData);
                  if (!mUiThreadHandler.post(uiRunnable)) {
                      throw new RuntimeException("Unable to send callback to UI thread!");
                  }
              } else {
                  mListener.onFrameReceived(this, input, mUserData);
              }
          } else {
              throw new RuntimeException("CallbackFilter received frame, but no listener set!");
          }
      }
  
  }
  