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	/*
	* Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.smartcardio;

	import java.util.Arrays;

	/**
	* A response APDU as defined in ISO/IEC 7816-4. It consists of a conditional
	* body and a two byte trailer.
	* This class does not attempt to verify that the APDU encodes a semantically
	* valid response.
	*
	* <p>Instances of this class are immutable. Where data is passed in or out
	* via byte arrays, defensive cloning is performed.
	*
	* @see CommandAPDU
	* @see CardChannel#transmit CardChannel.transmit
	*
	* @since 1.6
	* @author Andreas Sterbenz
	* @author JSR 268 Expert Group
	*/
	public final class ResponseAPDU implements java.io.Serializable {

	private static final long serialVersionUID = 6962744978375594225L;

	/** @serial */
	private byte[] apdu;

	/**
	* Constructs a ResponseAPDU from a byte array containing the complete
	* APDU contents (conditional body and trailed).
	*
	* <p>Note that the byte array is cloned to protect against subsequent
	* modification.
	*
	* @param apdu the complete response APDU
	*
	* @throws NullPointerException if apdu is null
	* @throws IllegalArgumentException if apdu.length is less than 2
	*/
	public ResponseAPDU(byte[] apdu) {
	apdu = apdu.clone();
	check(apdu);
	this.apdu = apdu;
	}

	private static void check(byte[] apdu) {
	if (apdu.length < 2) {
	throw new IllegalArgumentException("apdu must be at least 2 bytes long");
	}
	}

	/**
	* Returns the number of data bytes in the response body (Nr) or 0 if this
	* APDU has no body. This call is equivalent to
	* <code>getData().length</code>.
	*
	* @return the number of data bytes in the response body or 0 if this APDU
	* has no body.
	*/
	public int getNr() {
	return apdu.length - 2;
	}

	/**
	* Returns a copy of the data bytes in the response body. If this APDU as
	* no body, this method returns a byte array with a length of zero.
	*
	* @return a copy of the data bytes in the response body or the empty
	* byte array if this APDU has no body.
	*/
	public byte[] getData() {
	byte[] data = new byte[apdu.length - 2];
	System.arraycopy(apdu, 0, data, 0, data.length);
	return data;
	}

	/**
	* Returns the value of the status byte SW1 as a value between 0 and 255.
	*
	* @return the value of the status byte SW1 as a value between 0 and 255.
	*/
	public int getSW1() {
	return apdu[apdu.length - 2] & 0xff;
	}

	/**
	* Returns the value of the status byte SW2 as a value between 0 and 255.
	*
	* @return the value of the status byte SW2 as a value between 0 and 255.
	*/
	public int getSW2() {
	return apdu[apdu.length - 1] & 0xff;
	}

	/**
	* Returns the value of the status bytes SW1 and SW2 as a single
	* status word SW.
	* It is defined as
	* {@code (getSW1() << 8) \| getSW2()}
	*
	* @return the value of the status word SW.
	*/
	public int getSW() {
	return (getSW1() << 8) \| getSW2();
	}

	/**
	* Returns a copy of the bytes in this APDU.
	*
	* @return a copy of the bytes in this APDU.
	*/
	public byte[] getBytes() {
	return apdu.clone();
	}

	/**
	* Returns a string representation of this response APDU.
	*
	* @return a String representation of this response APDU.
	*/
	public String toString() {
	return "ResponseAPDU: " + apdu.length + " bytes, SW="
	+ Integer.toHexString(getSW());
	}

	/**
	* Compares the specified object with this response APDU for equality.
	* Returns true if the given object is also a ResponseAPDU and its bytes are
	* identical to the bytes in this ResponseAPDU.
	*
	* @param obj the object to be compared for equality with this response APDU
	* @return true if the specified object is equal to this response APDU
	*/
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj instanceof ResponseAPDU == false) {
	return false;
	}
	ResponseAPDU other = (ResponseAPDU)obj;
	return Arrays.equals(this.apdu, other.apdu);
	}

	/**
	* Returns the hash code value for this response APDU.
	*
	* @return the hash code value for this response APDU.
	*/
	public int hashCode() {
	return Arrays.hashCode(apdu);
	}

	private void readObject(java.io.ObjectInputStream in)
	throws java.io.IOException, ClassNotFoundException {
	apdu = (byte[])in.readUnshared();
	check(apdu);
	}

	}

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