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;
  
  /**
   * @hide
   */
  public class StreamPort extends InputPort {
  
      private Frame mFrame;
      private boolean mPersistent;
  
      public StreamPort(Filter filter, String name) {
          super(filter, name);
      }
  
      @Override
      public void clear() {
          if (mFrame != null) {
              mFrame.release();
              mFrame = null;
          }
      }
  
      @Override
      public void setFrame(Frame frame) {
          assignFrame(frame, true);
      }
  
      @Override
      public void pushFrame(Frame frame) {
          assignFrame(frame, false);
      }
  
      protected synchronized void assignFrame(Frame frame, boolean persistent) {
          assertPortIsOpen();
          checkFrameType(frame, persistent);
  
          if (persistent) {
              if (mFrame != null) {
                  mFrame.release();
              }
          } else if (mFrame != null) {
              throw new RuntimeException(
                  "Attempting to push more than one frame on port: " + this + "!");
          }
          mFrame = frame.retain();
          mFrame.markReadOnly();
          mPersistent = persistent;
      }
  
      @Override
      public synchronized Frame pullFrame() {
          // Make sure we have a frame
          if (mFrame == null) {
              throw new RuntimeException("No frame available to pull on port: " + this + "!");
          }
  
          // Return a retained result
          Frame result = mFrame;
          if (mPersistent) {
              mFrame.retain();
          } else {
              mFrame = null;
          }
          return result;
      }
  
      @Override
      public synchronized boolean hasFrame() {
          return mFrame != null;
      }
  
      @Override
      public String toString() {
          return "input " + super.toString();
      }
  
      @Override
      public synchronized void transfer(FilterContext context) {
          if (mFrame != null) {
              checkFrameManager(mFrame, context);
          }
      }
  }
  