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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.Tag;
     20 import android.os.Bundle;
     21 import android.os.RemoteException;
     22 
     23 import java.io.IOException;
     24 
     25 /**
     26  * Provides access to NFC-B (ISO 14443-3B) properties and I/O operations on a {@link Tag}.
     27  *
     28  * <p>Acquire a {@link NfcB} object using {@link #get}.
     29  * <p>The primary NFC-B I/O operation is {@link #transceive}. Applications must
     30  * implement their own protocol stack on top of {@link #transceive}.
     31  *
     32  * <p class="note"><strong>Note:</strong> Methods that perform I/O operations
     33  * require the {@link android.Manifest.permission#NFC} permission.
     34  */
     35 public final class NfcB extends BasicTagTechnology {
     36     /** @hide */
     37     public static final String EXTRA_APPDATA = "appdata";
     38     /** @hide */
     39     public static final String EXTRA_PROTINFO = "protinfo";
     40 
     41     private byte[] mAppData;
     42     private byte[] mProtInfo;
     43 
     44     /**
     45      * Get an instance of {@link NfcB} for the given tag.
     46      * <p>Returns null if {@link NfcB} was not enumerated in {@link Tag#getTechList}.
     47      * This indicates the tag does not support NFC-B.
     48      * <p>Does not cause any RF activity and does not block.
     49      *
     50      * @param tag an NFC-B compatible tag
     51      * @return NFC-B object
     52      */
     53     public static NfcB get(Tag tag) {
     54         if (!tag.hasTech(TagTechnology.NFC_B)) return null;
     55         try {
     56             return new NfcB(tag);
     57         } catch (RemoteException e) {
     58             return null;
     59         }
     60     }
     61 
     62     /** @hide */
     63     public NfcB(Tag tag) throws RemoteException {
     64         super(tag, TagTechnology.NFC_B);
     65         Bundle extras = tag.getTechExtras(TagTechnology.NFC_B);
     66         mAppData = extras.getByteArray(EXTRA_APPDATA);
     67         mProtInfo = extras.getByteArray(EXTRA_PROTINFO);
     68     }
     69 
     70     /**
     71      * Return the Application Data bytes from ATQB/SENSB_RES at tag discovery.
     72      *
     73      * <p>Does not cause any RF activity and does not block.
     74      *
     75      * @return Application Data bytes from ATQB/SENSB_RES bytes
     76      */
     77     public byte[] getApplicationData() {
     78         return mAppData;
     79     }
     80 
     81     /**
     82      * Return the Protocol Info bytes from ATQB/SENSB_RES at tag discovery.
     83      *
     84      * <p>Does not cause any RF activity and does not block.
     85      *
     86      * @return Protocol Info bytes from ATQB/SENSB_RES bytes
     87      */
     88     public byte[] getProtocolInfo() {
     89         return mProtInfo;
     90     }
     91 
     92     /**
     93      * Send raw NFC-B commands to the tag and receive the response.
     94      *
     95      * <p>Applications must not append the EoD (CRC) to the payload,
     96      * it will be automatically calculated.
     97      * <p>Applications must not send commands that manage the polling
     98      * loop and initialization (SENSB_REQ, SLOT_MARKER etc).
     99      *
    100      * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes
    101      * that can be sent with {@link #transceive}.
    102      *
    103      * <p>This is an I/O operation and will block until complete. It must
    104      * not be called from the main application thread. A blocked call will be canceled with
    105      * {@link IOException} if {@link #close} is called from another thread.
    106      *
    107      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
    108      *
    109      * @param data bytes to send
    110      * @return bytes received in response
    111      * @throws TagLostException if the tag leaves the field
    112      * @throws IOException if there is an I/O failure, or this operation is canceled
    113      */
    114     public byte[] transceive(byte[] data) throws IOException {
    115         return transceive(data, true);
    116     }
    117 
    118     /**
    119      * Return the maximum number of bytes that can be sent with {@link #transceive}.
    120      * @return the maximum number of bytes that can be sent with {@link #transceive}.
    121      */
    122     public int getMaxTransceiveLength() {
    123         return getMaxTransceiveLengthInternal();
    124     }
    125 }
    126