/*
* @(#)HexBinaryAttribute.java
*
* Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistribution in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
* AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
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* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
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*
* You acknowledge that this software is not designed or intended for use in
* the design, construction, operation or maintenance of any nuclear facility.
*/
package com.sun.xacml.attr;
import java.net.URI;
import java.util.Arrays;
import org.w3c.dom.Node;
import com.sun.xacml.ParsingException;
/**
* Representation of an xsi:hexBinary value. This class supports parsing xsi:hexBinary values. All
* objects of this class are immutable and all methods of the class are thread-safe.
*
* @since 1.0
* @author Steve Hanna
*/
public class HexBinaryAttribute extends AttributeValue {
/**
* Official name of this type
*/
public static final String identifier = "http://www.w3.org/2001/XMLSchema#hexBinary";
/**
* URI version of name for this type
*/
private static final URI identifierURI = URI.create(identifier);
/**
* The actual binary value that this object represents.
*/
private byte[] value;
/**
* The value returned by toString(). Cached, but only generated if needed.
*/
private String strValue;
/**
* Creates a new <code>HexBinaryAttribute</code> that represents the byte [] value supplied.
*
* @param value
* the <code>byte []</code> value to be represented
*/
public HexBinaryAttribute(byte[] value) {
super(identifierURI);
// This will throw a NullPointerException if value == null.
// That's what we want in that case.
this.value = (byte[]) value.clone();
}
/**
* Returns a new <code>HexBinaryAttribute</code> that represents the xsi:hexBinary at a
* particular DOM node.
*
* @param root
* the <code>Node</code> that contains the desired value
* @return a new <code>HexBinaryAttribute</code> representing the appropriate value
* @exception ParsingException
* if a parsing error occurs
*/
public static HexBinaryAttribute getInstance(Node root) throws ParsingException {
return getInstance(root.getFirstChild().getNodeValue());
}
/**
* Returns a new <code>HexBinaryAttribute</code> that represents the xsi:hexBinary value
* indicated by the string provided.
*
* @param value
* a string representing the desired value
* @return a new <code>HexBinaryAttribute</code> representing the desired value
* @exception ParsingException
* if a parsing error occurs
*/
public static HexBinaryAttribute getInstance(String value) throws ParsingException {
byte[] bytes = hexToBin(value);
if (bytes == null)
throw new ParsingException("Couldn't parse purported " + "hex string: " + value);
return new HexBinaryAttribute(bytes);
}
/**
* Returns the <code>byte []</code> value represented by this object. Note that this value is
* cloned before returning to prevent unauthorized modifications.
*
* @return the <code>byte []</code> value
*/
public byte[] getValue() {
return (byte[]) value.clone();
}
/**
* Returns the hashcode value used to index and compare this object with others of the same
* type. Typically this is the hashcode of the backing data object.
*
* @return the object's hashcode value
*/
public int hashCode() {
int code = (int) (value[0]);
for (int i = 1; i < value.length; i++) {
code *= 31;
code += (int) (value[i]);
}
return code;
}
/**
* Returns true if the input is an instance of this class and if its value equals the value
* contained in this class.
*
* @param o
* the object to compare
*
* @return true if this object and the input represent the same value
*/
public boolean equals(Object o) {
if (!(o instanceof HexBinaryAttribute))
return false;
HexBinaryAttribute other = (HexBinaryAttribute) o;
return Arrays.equals(value, other.value);
}
/**
* Return the int value of a hex character. Return -1 if the character is not a valid hex
* character.
*/
private static int hexToBinNibble(char c) {
int result = -1;
if ((c >= '0') && (c <= '9'))
result = (c - '0');
else {
if ((c >= 'a') && (c <= 'f'))
result = (c - 'a') + 10;
else {
if ((c >= 'A') && (c <= 'F'))
result = (c - 'A') + 10;
// else pick up the -1 value set above
}
}
return result;
}
/**
* Parse a hex string, returning a new byte array containing the value. Return null in case of a
* parsing error.
*
* @param hex
* the hex string
* @return a new byte array containing the value (or null)
*/
private static byte[] hexToBin(String hex) {
int len = hex.length();
// Must have an even number of hex digits
if (len % 2 != 0)
return null;
int byteCount = len / 2;
byte[] bytes = new byte[byteCount];
int charIndex = 0;
for (int byteIndex = 0; byteIndex < byteCount; byteIndex++) {
int hiNibble = hexToBinNibble(hex.charAt(charIndex++));
int loNibble = hexToBinNibble(hex.charAt(charIndex++));
if ((hiNibble < 0) || (loNibble < 0))
return null;
bytes[byteIndex] = (byte) (hiNibble * 16 + loNibble);
}
return bytes;
}
/**
* Return the hex character for a particular nibble (half a byte).
*
* @param nibble
* a value 0-15
* @return hex character for that nibble (using A-F for 10-15)
*/
private static char binToHexNibble(int nibble) {
char result = (char) 0;
if (nibble < 10)
result = (char) (nibble + '0');
else
result = (char) ((nibble - 10) + 'A');
return result;
}
/**
* Return a straight hexadecimal conversion of a byte array. This is a String containing only
* hex digits.
*
* @param bytes
* the byte array
* @return the hex version
*/
private static String binToHex(byte[] bytes) {
int byteLength = bytes.length;
char[] chars = new char[byteLength * 2];
int charIndex = 0;
for (int byteIndex = 0; byteIndex < byteLength; byteIndex++) {
byte b = bytes[byteIndex];
chars[charIndex++] = binToHexNibble((b >> 4) & 0xf);
chars[charIndex++] = binToHexNibble(b & 0xf);
}
return new String(chars);
}
/**
* Returns a String representation.
*
* @return the String representation
*/
public String toString() {
if (strValue == null)
strValue = binToHex(value);
return "HexBinaryAttribute: [\n" + strValue + "]\n";
}
/**
*
*/
public String encode() {
if (strValue == null)
strValue = binToHex(value);
return strValue;
}
}