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 java.lang.reflect.Field;
  
  /**
   * @hide
   */
  public class FieldPort extends InputPort {
  
      protected Field mField;
      protected boolean mHasFrame;
      protected boolean mValueWaiting = false;
      protected Object mValue;
  
      public FieldPort(Filter filter, String name, Field field, boolean hasDefault) {
          super(filter, name);
          mField = field;
          mHasFrame = hasDefault;
      }
  
      @Override
      public void clear() {
      }
  
      @Override
      public void pushFrame(Frame frame) {
          setFieldFrame(frame, false);
      }
  
      @Override
      public void setFrame(Frame frame) {
          setFieldFrame(frame, true);
      }
  
      @Override
      public Object getTarget() {
          try {
              return mField.get(mFilter);
          } catch (IllegalAccessException e) {
              return null;
          }
      }
  
      @Override
      public synchronized void transfer(FilterContext context) {
          if (mValueWaiting) {
              try {
                  mField.set(mFilter, mValue);
              } catch (IllegalAccessException e) {
                  throw new RuntimeException(
                      "Access to field '" + mField.getName() + "' was denied!");
              }
              mValueWaiting = false;
              if (context != null) {
                  mFilter.notifyFieldPortValueUpdated(mName, context);
              }
          }
      }
  
      @Override
      public synchronized Frame pullFrame() {
          throw new RuntimeException("Cannot pull frame on " + this + "!");
      }
  
      @Override
      public synchronized boolean hasFrame() {
          return mHasFrame;
      }
  
      @Override
      public synchronized boolean acceptsFrame() {
          return !mValueWaiting;
      }
  
      @Override
      public String toString() {
          return "field " + super.toString();
      }
  
      protected synchronized void setFieldFrame(Frame frame, boolean isAssignment) {
          assertPortIsOpen();
          checkFrameType(frame, isAssignment);
  
          // Store the object value
          Object value = frame.getObjectValue();
          if ((value == null && mValue != null) || !value.equals(mValue)) {
              mValue = value;
              mValueWaiting = true;
          }
  
          // Since a frame was set, mark this port as having a frame to pull
          mHasFrame = true;
      }
  }
  