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/*
* Copyright (C) 2010 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.nfc;
import android.nfc.technology.IsoDep;
import android.nfc.technology.MifareClassic;
import android.nfc.technology.MifareUltralight;
import android.nfc.technology.NfcV;
import android.nfc.technology.Ndef;
import android.nfc.technology.NfcA;
import android.nfc.technology.NfcB;
import android.nfc.technology.NfcF;
import android.nfc.technology.TagTechnology;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.os.RemoteException;
import java.util.Arrays;
/**
* Represents a (generic) discovered tag.
* <p>
* A tag is a passive NFC element, such as NFC Forum Tag's, Mifare class Tags,
* Sony Felica Tags.
* <p>
* Tag's have a type and usually have a UID.
* <p>
* {@link Tag} objects are passed to applications via the {@link NfcAdapter#EXTRA_TAG} extra
* in {@link NfcAdapter#ACTION_TAG_DISCOVERED} intents. A {@link Tag} object is immutable
* and represents the state of the tag at the time of discovery. It can be
* directly queried for its UID and Type, or used to create a {@link TagTechnology}
* (with {@link Tag#getTechnology(int)}).
* <p>
* A {@link Tag} can be used to create a {@link TagTechnology} only while the tag is in
* range. If it is removed and then returned to range, then the most recent
* {@link Tag} object (in {@link NfcAdapter#ACTION_TAG_DISCOVERED}) should be used to create a
* {@link TagTechnology}.
* <p>This is an immutable data class. All properties are set at Tag discovery
* time and calls on this class will retrieve those read-only properties, and
* not cause any further RF activity or block. Note however that arrays passed to and
* returned by this class are *not* cloned, so be careful not to modify them.
* @hide
*/
public class Tag implements Parcelable {
/*package*/ final byte[] mId;
/*package*/ final int[] mTechList;
/*package*/ final Bundle[] mTechExtras;
/*package*/ final int mServiceHandle; // for use by NFC service, 0 indicates a mock
/**
* Hidden constructor to be used by NFC service and internal classes.
* @hide
*/
public Tag(byte[] id, int[] techList, Bundle[] techListExtras, int serviceHandle) {
if (techList == null) {
throw new IllegalArgumentException("rawTargets cannot be null");
}
mId = id;
mTechList = Arrays.copyOf(techList, techList.length);
// Ensure mTechExtras is as long as mTechList
mTechExtras = Arrays.copyOf(techListExtras, techList.length);
mServiceHandle = serviceHandle;
}
/**
* Construct a mock Tag.
* <p>This is an application constructed tag, so NfcAdapter methods on this
* Tag such as {@link #getTechnology} may fail with
* {@link IllegalArgumentException} since it does not represent a physical Tag.
* <p>This constructor might be useful for mock testing.
* @param id The tag identifier, can be null
* @param techList must not be null
* @return freshly constructed tag
*/
public static Tag createMockTag(byte[] id, int[] techList, Bundle[] techListExtras) {
// set serviceHandle to 0 to indicate mock tag
return new Tag(id, techList, techListExtras, 0);
}
/**
* For use by NfcService only.
* @hide
*/
public int getServiceHandle() {
return mServiceHandle;
}
/**
* Get the Tag Identifier (if it has one).
* <p>Tag ID is usually a serial number for the tag.
*
* @return ID, or null if it does not exist
*/
public byte[] getId() {
return mId;
}
/**
* Returns technologies present in the tag that this implementation understands,
* or a zero length array if there are no supported technologies on this tag.
*
* The elements of the list are guaranteed be one of the constants defined in
* {@link TagTechnology}.
*
* The ordering of the returned array is undefined and should not be relied upon.
*/
public int[] getTechnologyList() {
return Arrays.copyOf(mTechList, mTechList.length);
}
/**
* Returns the technology, or null if not present
*/
public TagTechnology getTechnology(int tech) {
int pos = -1;
for (int idx = 0; idx < mTechList.length; idx++) {
if (mTechList[idx] == tech) {
pos = idx;
break;
}
}
if (pos < 0) {
return null;
}
Bundle extras = mTechExtras[pos];
NfcAdapter adapter = NfcAdapter.getDefaultAdapter();
try {
switch (tech) {
case TagTechnology.NFC_A: {
return new NfcA(adapter, this, extras);
}
case TagTechnology.NFC_B: {
return new NfcB(adapter, this, extras);
}
case TagTechnology.ISO_DEP: {
return new IsoDep(adapter, this, extras);
}
case TagTechnology.NFC_V: {
return new NfcV(adapter, this, extras);
}
case TagTechnology.NDEF: {
return new Ndef(adapter, this, tech, extras);
}
case TagTechnology.NFC_F: {
return new NfcF(adapter, this, extras);
}
case TagTechnology.MIFARE_CLASSIC: {
return new MifareClassic(adapter, this, extras);
}
case TagTechnology.MIFARE_ULTRALIGHT: {
return new MifareUltralight(adapter, this, extras);
}
default: {
throw new UnsupportedOperationException("Tech " + tech + " not supported");
}
}
} catch (RemoteException e) {
return null;
}
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("TAG ")
.append("uid = ")
.append(mId)
.append(" Tech [");
for (int i : mTechList) {
sb.append(i)
.append(", ");
}
return sb.toString();
}
/*package*/ static byte[] readBytesWithNull(Parcel in) {
int len = in.readInt();
byte[] result = null;
if (len >= 0) {
result = new byte[len];
in.readByteArray(result);
}
return result;
}
/*package*/ static void writeBytesWithNull(Parcel out, byte[] b) {
if (b == null) {
out.writeInt(-1);
return;
}
out.writeInt(b.length);
out.writeByteArray(b);
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
writeBytesWithNull(dest, mId);
dest.writeInt(mTechList.length);
dest.writeIntArray(mTechList);
dest.writeTypedArray(mTechExtras, 0);
dest.writeInt(mServiceHandle);
}
public static final Parcelable.Creator<Tag> CREATOR =
new Parcelable.Creator<Tag>() {
@Override
public Tag createFromParcel(Parcel in) {
// Tag fields
byte[] id = Tag.readBytesWithNull(in);
int[] techList = new int[in.readInt()];
in.readIntArray(techList);
Bundle[] techExtras = in.createTypedArray(Bundle.CREATOR);
int serviceHandle = in.readInt();
return new Tag(id, techList, techExtras, serviceHandle);
}
@Override
public Tag[] newArray(int size) {
return new Tag[size];
}
};
}
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