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      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 
     18 package android.filterfw.core;
     19 
     20 import java.lang.reflect.Field;
     21 
     22 /**
     23  * @hide
     24  */
     25 public class FieldPort extends InputPort {
     26 
     27     protected Field mField;
     28     protected boolean mHasFrame;
     29     protected boolean mValueWaiting = false;
     30     protected Object mValue;
     31 
     32     public FieldPort(Filter filter, String name, Field field, boolean hasDefault) {
     33         super(filter, name);
     34         mField = field;
     35         mHasFrame = hasDefault;
     36     }
     37 
     38     @Override
     39     public void clear() {
     40     }
     41 
     42     @Override
     43     public void pushFrame(Frame frame) {
     44         setFieldFrame(frame, false);
     45     }
     46 
     47     @Override
     48     public void setFrame(Frame frame) {
     49         setFieldFrame(frame, true);
     50     }
     51 
     52     @Override
     53     public Object getTarget() {
     54         try {
     55             return mField.get(mFilter);
     56         } catch (IllegalAccessException e) {
     57             return null;
     58         }
     59     }
     60 
     61     @Override
     62     public synchronized void transfer(FilterContext context) {
     63         if (mValueWaiting) {
     64             try {
     65                 mField.set(mFilter, mValue);
     66             } catch (IllegalAccessException e) {
     67                 throw new RuntimeException(
     68                     "Access to field '" + mField.getName() + "' was denied!");
     69             }
     70             mValueWaiting = false;
     71             if (context != null) {
     72                 mFilter.notifyFieldPortValueUpdated(mName, context);
     73             }
     74         }
     75     }
     76 
     77     @Override
     78     public synchronized Frame pullFrame() {
     79         throw new RuntimeException("Cannot pull frame on " + this + "!");
     80     }
     81 
     82     @Override
     83     public synchronized boolean hasFrame() {
     84         return mHasFrame;
     85     }
     86 
     87     @Override
     88     public synchronized boolean acceptsFrame() {
     89         return !mValueWaiting;
     90     }
     91 
     92     @Override
     93     public String toString() {
     94         return "field " + super.toString();
     95     }
     96 
     97     protected synchronized void setFieldFrame(Frame frame, boolean isAssignment) {
     98         assertPortIsOpen();
     99         checkFrameType(frame, isAssignment);
    100 
    101         // Store the object value
    102         Object value = frame.getObjectValue();
    103         if ((value == null && mValue != null) || !value.equals(mValue)) {
    104             mValue = value;
    105             mValueWaiting = true;
    106         }
    107 
    108         // Since a frame was set, mark this port as having a frame to pull
    109         mHasFrame = true;
    110     }
    111 }
    112