/*
* @(#)StringAttribute.java
*
* Copyright 2003-2005 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
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*
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* 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
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*/
package com.sun.xacml.attr;
import java.net.URI;
import org.w3c.dom.Node;
import com.sun.xacml.ParsingException;
/**
* Representation of an xs:string value. This class supports parsing
* xs:string values. All objects of this class are immutable and
* all methods of the class are thread-safe.
* <p>
* Note that there was some confusion in the XACML specification
* about whether this datatype should be able to handle XML elements (ie,
* whether <AttributeValue DataType="...string"><foo/>
* </AttributeValue> is valid). This has been clarified to provide
* the correct requirement that a string may not contain mixed content (ie,
* the example provided here is invalid). If you need to specify something
* like this with the string datatype, then you must escape the
* <code><</code> and <code>></code> characters.
*
* @since 1.0
* @author Marco Barreno
* @author Seth Proctor
* @author Steve Hanna
*/
public class StringAttribute extends AttributeValue
{
/**
* Official name of this type
*/
public static final String identifier =
TypeIdentifierConstants.STRING;
/**
* 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 String value that this object represents.
*/
private String value;
/**
* Creates a new <code>StringAttribute</code> that represents
* the String value supplied.
*
* @param value the <code>String</code> value to be represented
*/
public StringAttribute(String value) {
super(identifierURI);
// Shouldn't happen, but just in case...
if (earlyException != null) {
throw earlyException;
}
if (value == null) {
this.value = "";
} else {
this.value = value;
}
}
/**
* Returns a new <code>StringAttribute</code> that represents
* the xs:string at a particular DOM node.
*
* @param root the <code>Node</code> that contains the desired value
* @return a new <code>StringAttribute</code> representing the
* appropriate value (null if there is a parsing error)
* @throws ParsingException
*/
public static StringAttribute getInstance(Node root)
throws ParsingException {
Node node = root.getFirstChild();
// Strings are allowed to have an empty AttributeValue element and are
// just treated as empty strings...we have to handle this case
if (node == null) {
return new StringAttribute("");
}
// get the type of the node
short type = node.getNodeType();
// now see if we have (effectively) a simple string value
if ((type == Node.TEXT_NODE) || (type == Node.CDATA_SECTION_NODE) ||
(type == Node.COMMENT_NODE)) {
return getInstance(node.getNodeValue());
}
// there is some confusion in the specifications about what should
// happen at this point, but the strict reading of the XMLSchema
// specification suggests that this should be an error
throw new ParsingException("Can't create a StringAttribute from "
+ "given xml node type: " + root.getNodeType());
}
/**
* Returns a new <code>StringAttribute</code> that represents
* the xs:string value indicated by the <code>String</code> provided.
*
* @param value a string representing the desired value
* @return a new <code>StringAttribute</code> representing the
* appropriate value
*/
public static StringAttribute getInstance(String value) {
return new StringAttribute(value);
}
/**
* Returns the <code>String</code> value represented by this object.
*
* @return the <code>String</code> value
*/
public String getValue() {
return this.value;
}
/**
* 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 StringAttribute)) {
return false;
}
StringAttribute other = (StringAttribute)o;
return this.value.equals(other.value);
}
/**
* 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() {
return this.value.hashCode();
}
/**
* Converts to a String representation.
*
* @return the String representation
*/
public String toString() {
return "StringAttribute: \"" + this.value + "\"";
}
/**
* @return The String encoding this AttributeValue.
*/
public String encode() {
return this.value;
}
}