/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.nfc.tech;
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import android.nfc.Tag;
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import java.io.Closeable;
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import java.io.IOException;
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/**
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* {@link TagTechnology} is an interface to a technology in a {@link Tag}.
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* <p>
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* Obtain a {@link TagTechnology} implementation by calling the static method <code>get()</code>
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* on the implementation class.
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* <p>
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* NFC tags are based on a number of independently developed technologies and offer a
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* wide range of capabilities. The
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* {@link TagTechnology} implementations provide access to these different
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* technologies and capabilities. Some sub-classes map to technology
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* specification (for example {@link NfcA}, {@link IsoDep}, others map to
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* pseudo-technologies or capabilities (for example {@link Ndef}, {@link NdefFormatable}).
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* <p>
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* It is mandatory for all Android NFC devices to provide the following
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* {@link TagTechnology} implementations.
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* <ul>
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* <li>{@link NfcA} (also known as ISO 14443-3A)
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* <li>{@link NfcB} (also known as ISO 14443-3B)
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* <li>{@link NfcF} (also known as JIS 6319-4)
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* <li>{@link NfcV} (also known as ISO 15693)
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* <li>{@link IsoDep}
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* <li>{@link Ndef} on NFC Forum Type 1, Type 2, Type 3 or Type 4 compliant tags
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* </ul>
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* It is optional for Android NFC devices to provide the following
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* {@link TagTechnology} implementations. If it is not provided, the
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* Android device will never enumerate that class via {@link Tag#getTechList}.
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* <ul>
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* <li>{@link MifareClassic}
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* <li>{@link MifareUltralight}
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* <li>{@link NfcBarcode}
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* <li>{@link NdefFormatable} must only be enumerated on tags for which this Android device
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* is capable of formatting. Proprietary knowledge is often required to format a tag
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* to make it NDEF compatible.
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* </ul>
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* <p>
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* {@link TagTechnology} implementations provide methods that fall into two classes:
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* <em>cached getters</em> and <em>I/O operations</em>.
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* <h4>Cached getters</h4>
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* These methods (usually prefixed by <code>get</code> or <code>is</code>) return
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* properties of the tag, as determined at discovery time. These methods will never
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* block or cause RF activity, and do not require {@link #connect} to have been called.
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* They also never update, for example if a property is changed by an I/O operation with a tag
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* then the cached getter will still return the result from tag discovery time.
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* <h4>I/O operations</h4>
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* I/O operations may require RF activity, and may block. They have the following semantics.
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* <ul>
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* <li>{@link #connect} must be called before using any other I/O operation.
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* <li>{@link #close} must be called after completing I/O operations with a
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* {@link TagTechnology}, and it will cancel all other blocked I/O operations on other threads
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* (including {@link #connect} with {@link IOException}.
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* <li>Only one {@link TagTechnology} can be connected at a time. Other calls to
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* {@link #connect} will return {@link IOException}.
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* <li>I/O operations may block, and should never be called on the main application
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* thread.
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* </ul>
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*
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* <p class="note"><strong>Note:</strong> Methods that perform I/O operations
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* require the {@link android.Manifest.permission#NFC} permission.
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*/
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public interface TagTechnology extends Closeable {
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/**
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* This technology is an instance of {@link NfcA}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int NFC_A = 1;
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/**
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* This technology is an instance of {@link NfcB}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int NFC_B = 2;
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/**
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* This technology is an instance of {@link IsoDep}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int ISO_DEP = 3;
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/**
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* This technology is an instance of {@link NfcF}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int NFC_F = 4;
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/**
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* This technology is an instance of {@link NfcV}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int NFC_V = 5;
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/**
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* This technology is an instance of {@link Ndef}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int NDEF = 6;
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/**
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* This technology is an instance of {@link NdefFormatable}.
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* <p>Support for this technology type is mandatory.
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* @hide
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*/
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public static final int NDEF_FORMATABLE = 7;
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/**
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* This technology is an instance of {@link MifareClassic}.
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* <p>Support for this technology type is optional. If a stack doesn't support this technology
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* type tags using it must still be discovered and present the lower level radio interface
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* technologies in use.
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* @hide
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*/
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public static final int MIFARE_CLASSIC = 8;
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/**
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* This technology is an instance of {@link MifareUltralight}.
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* <p>Support for this technology type is optional. If a stack doesn't support this technology
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* type tags using it must still be discovered and present the lower level radio interface
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* technologies in use.
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* @hide
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*/
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public static final int MIFARE_ULTRALIGHT = 9;
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/**
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* This technology is an instance of {@link NfcBarcode}.
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* <p>Support for this technology type is optional. If a stack doesn't support this technology
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* type tags using it must still be discovered and present the lower level radio interface
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* technologies in use.
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* @hide
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*/
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public static final int NFC_BARCODE = 10;
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/**
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* Get the {@link Tag} object backing this {@link TagTechnology} object.
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* @return the {@link Tag} backing this {@link TagTechnology} object.
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*/
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public Tag getTag();
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/**
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* Enable I/O operations to the tag from this {@link TagTechnology} object.
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* <p>May cause RF activity and may block. Must not be called
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* from the main application thread. A blocked call will be canceled with
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* {@link IOException} by calling {@link #close} from another thread.
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* <p>Only one {@link TagTechnology} object can be connected to a {@link Tag} at a time.
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* <p>Applications must call {@link #close} when I/O operations are complete.
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*
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* <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
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*
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* @see #close()
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* @throws TagLostException if the tag leaves the field
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* @throws IOException if there is an I/O failure, or connect is canceled
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*/
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public void connect() throws IOException;
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/**
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* Re-connect to the {@link Tag} associated with this connection. Reconnecting to a tag can be
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* used to reset the state of the tag itself.
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*
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* <p>May cause RF activity and may block. Must not be called
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* from the main application thread. A blocked call will be canceled with
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* {@link IOException} by calling {@link #close} from another thread.
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*
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* <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
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*
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* @see #connect()
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* @see #close()
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* @throws TagLostException if the tag leaves the field
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* @throws IOException if there is an I/O failure, or connect is canceled
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* @hide
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*/
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public void reconnect() throws IOException;
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/**
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* Disable I/O operations to the tag from this {@link TagTechnology} object, and release resources.
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* <p>Also causes all blocked I/O operations on other thread to be canceled and
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* return with {@link IOException}.
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*
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* <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
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*
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* @see #connect()
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*/
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public void close() throws IOException;
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/**
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* Helper to indicate if I/O operations should be possible.
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*
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* <p>Returns true if {@link #connect} has completed, and {@link #close} has not been
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* called, and the {@link Tag} is not known to be out of range.
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* <p>Does not cause RF activity, and does not block.
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*
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* @return true if I/O operations should be possible
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*/
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public boolean isConnected();
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}
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