/*
* @(#)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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* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* 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 com.sun.xacml.Constants;
import com.sun.xacml.ParsingException;
import java.net.URI;
import java.util.Arrays;
import org.w3c.dom.Node;
/**
* 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 =
TypeIdentifierConstants.HEXBINARY;
/**
* URI version of name for this type
* <p>
* This field is initialized by a static initializer so that
* we can catch any exceptions thrown by URI(String) and
* transform them into a RuntimeException, since this should
* never happen but should be reported properly if it ever does.
*/
private static URI identifierURI;
/**
* RuntimeException that wraps an Exception thrown during the
* creation of identifierURI, null if none.
*/
private static RuntimeException earlyException;
/**
* Static initializer that initializes the identifierURI
* class field so that we can catch any exceptions thrown
* by URI(String) and transform them into a RuntimeException.
* Such exceptions should never happen but should be reported
* properly if they ever do.
*/
static {
try {
identifierURI = URI.create(identifier);
} catch (IllegalArgumentException e) {
earlyException = e;
}
}
/**
* 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);
// Shouldn't happen, but just in case...
if (earlyException != null) {
throw earlyException;
}
// 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 {
if (root.getFirstChild() != null) {
return getInstance(root.getFirstChild().getNodeValue());
}
throw new ParsingException("Error while parsing"
+ "a HexBinaryAttribute");
}
/**
* 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 {
if (value == null) {
throw new ParsingException("Can't create a "
+ "HexBinaryAttribute from null input");
}
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[])this.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 = this.value[0];
for (int i = 1; i < this.value.length; i++) {
code *= 31;
code += this.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(this.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 (this.strValue == null) {
this.strValue = binToHex(this.value);
}
return "HexBinaryAttribute: [" + Constants.nl
+ this.strValue + "]" + Constants.nl;
}
/**
* @return The String encoding this AttributeValue.
*/
public String encode() {
if (this.strValue == null) {
this.strValue = binToHex(this.value);
}
return this.strValue;
}
}