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      1 /*
      2  * Copyright (C) 2010 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 package android.nfc.tech;
     18 
     19 import android.nfc.ErrorCodes;
     20 import android.nfc.Tag;
     21 import android.nfc.TransceiveResult;
     22 import android.os.RemoteException;
     23 import android.util.Log;
     24 
     25 import java.io.IOException;
     26 
     27 /**
     28  * A base class for tag technologies that are built on top of transceive().
     29  */
     30 abstract class BasicTagTechnology implements TagTechnology {
     31     private static final String TAG = "NFC";
     32 
     33     final Tag mTag;
     34 
     35     boolean mIsConnected;
     36     int mSelectedTechnology;
     37 
     38     BasicTagTechnology(Tag tag, int tech) throws RemoteException {
     39         mTag = tag;
     40         mSelectedTechnology = tech;
     41     }
     42 
     43     @Override
     44     public Tag getTag() {
     45         return mTag;
     46     }
     47 
     48     /** Internal helper to throw IllegalStateException if the technology isn't connected */
     49     void checkConnected() {
     50        if ((mTag.getConnectedTechnology() != mSelectedTechnology) ||
     51                (mTag.getConnectedTechnology() == -1)) {
     52            throw new IllegalStateException("Call connect() first!");
     53        }
     54     }
     55 
     56     @Override
     57     public boolean isConnected() {
     58         if (!mIsConnected) {
     59             return false;
     60         }
     61 
     62         try {
     63             return mTag.getTagService().isPresent(mTag.getServiceHandle());
     64         } catch (RemoteException e) {
     65             Log.e(TAG, "NFC service dead", e);
     66             return false;
     67         }
     68     }
     69 
     70     @Override
     71     public void connect() throws IOException {
     72         try {
     73             int errorCode = mTag.getTagService().connect(mTag.getServiceHandle(),
     74                     mSelectedTechnology);
     75 
     76             if (errorCode == ErrorCodes.SUCCESS) {
     77                 // Store this in the tag object
     78                 mTag.setConnectedTechnology(mSelectedTechnology);
     79                 mIsConnected = true;
     80             } else if (errorCode == ErrorCodes.ERROR_NOT_SUPPORTED) {
     81                 throw new UnsupportedOperationException("Connecting to " +
     82                         "this technology is not supported by the NFC " +
     83                         "adapter.");
     84             } else {
     85                 throw new IOException();
     86             }
     87         } catch (RemoteException e) {
     88             Log.e(TAG, "NFC service dead", e);
     89             throw new IOException("NFC service died");
     90         }
     91     }
     92 
     93     /** @hide */
     94     @Override
     95     public void reconnect() throws IOException {
     96         if (!mIsConnected) {
     97             throw new IllegalStateException("Technology not connected yet");
     98         }
     99 
    100         try {
    101             int errorCode = mTag.getTagService().reconnect(mTag.getServiceHandle());
    102 
    103             if (errorCode != ErrorCodes.SUCCESS) {
    104                 mIsConnected = false;
    105                 mTag.setTechnologyDisconnected();
    106                 throw new IOException();
    107             }
    108         } catch (RemoteException e) {
    109             mIsConnected = false;
    110             mTag.setTechnologyDisconnected();
    111             Log.e(TAG, "NFC service dead", e);
    112             throw new IOException("NFC service died");
    113         }
    114     }
    115 
    116     @Override
    117     public void close() throws IOException {
    118         try {
    119             /* Note that we don't want to physically disconnect the tag,
    120              * but just reconnect to it to reset its state
    121              */
    122             mTag.getTagService().resetTimeouts();
    123             mTag.getTagService().reconnect(mTag.getServiceHandle());
    124         } catch (RemoteException e) {
    125             Log.e(TAG, "NFC service dead", e);
    126         } finally {
    127             mIsConnected = false;
    128             mTag.setTechnologyDisconnected();
    129         }
    130     }
    131 
    132     /** Internal getMaxTransceiveLength() */
    133     int getMaxTransceiveLengthInternal() {
    134         try {
    135             return mTag.getTagService().getMaxTransceiveLength(mSelectedTechnology);
    136         } catch (RemoteException e) {
    137             Log.e(TAG, "NFC service dead", e);
    138             return 0;
    139         }
    140     }
    141     /** Internal transceive */
    142     byte[] transceive(byte[] data, boolean raw) throws IOException {
    143         checkConnected();
    144 
    145         try {
    146             TransceiveResult result = mTag.getTagService().transceive(mTag.getServiceHandle(),
    147                     data, raw);
    148             if (result == null) {
    149                 throw new IOException("transceive failed");
    150             } else {
    151                 return result.getResponseOrThrow();
    152             }
    153         } catch (RemoteException e) {
    154             Log.e(TAG, "NFC service dead", e);
    155             throw new IOException("NFC service died");
    156         }
    157     }
    158 }
    159