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      */
get(Tag tag)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 */
NfcB(Tag tag)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      */
getApplicationData()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      */
getProtocolInfo()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      */
transceive(byte[] data)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      */
getMaxTransceiveLength()122     public int getMaxTransceiveLength() {
123         return getMaxTransceiveLengthInternal();
124     }
125 }
126