/*
* @(#)BooleanAttribute.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
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* 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,
* EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* 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.ParsingException;
import java.net.URI;
import org.w3c.dom.Node;
/**
* Representation of an xs:boolean value. This class supports parsing
* xs:boolean values. All objects of this class are immutable and
* all methods of the class are thread-safe.
*
* @since 1.0
* @author Marco Barreno
* @author Steve Hanna
*/
public class BooleanAttribute extends AttributeValue
{
/**
* Official name of this type
*/
public static final String identifier = TypeIdentifierConstants.BOOLEAN;
/**
* 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;
/**
* Single instance of BooleanAttribute that represents true.
* Initialized by the static initializer below.
*/
private static BooleanAttribute trueInstance;
/**
* Single instance of BooleanAttribute that represents false.
* Initialized by the static initializer below.
*/
private static BooleanAttribute falseInstance;
/**
* TODO hack? required for null value for defining missing
* attributes in the statusDetail
*/
private static BooleanAttribute invalidInstance;
/**
* Static initializer that initializes many static fields.
* <p>
* It is possible 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);
trueInstance = new BooleanAttribute(true);
falseInstance = new BooleanAttribute(false);
invalidInstance = new BooleanAttribute();
} catch (IllegalArgumentException e) {
earlyException = e;
}
}
/**
* The actual boolean value that this object represents.
*/
private boolean value;
private boolean valid = true;
/**
* Creates a new <code>BooleanAttribute</code> that represents
* the boolean value supplied.
* <p>
* This constructor is private because it should not be used by
* anyone other than the static initializer in this class.
* Instead, please use one of the getInstance methods, which
* will ensure that only two BooleanAttribute objects are created,
* thus avoiding excess object creation.
*/
protected BooleanAttribute(boolean value) {
super(identifierURI);
this.value = value;
}
private BooleanAttribute() {
super(identifierURI);
this.valid = false;
this.value = false;
}
/**
* Returns a <code>BooleanAttribute</code> that represents
* the xs:boolean at a particular DOM node.
*
* @param root the <code>Node</code> that contains the desired value
* @return a <code>BooleanAttribute</code> representing the
* appropriate value (null if there is a parsing error)
*
* @throws ParsingException
*/
public static BooleanAttribute getInstance(Node root)
throws ParsingException {
if (root.getFirstChild() != null) {
return getInstance(root.getFirstChild().getNodeValue());
}
throw new ParsingException("Error while parsing"
+ "a BooleanAttribute");
}
/**
* Returns a <code>BooleanAttribute</code> that represents
* the xs:boolean value indicated by the string provided.
*
* @param value a string representing the desired value
* @return a <code>BooleanAttribute</code> representing the
* appropriate value (null if there is a parsing error)
*
* @throws ParsingException
*/
public static BooleanAttribute getInstance(String value)
throws ParsingException {
if (value == null) {
return invalidInstance;
// throw new ParsingException("Can't create a "
// + "BooleanAttribute from null input");
}
// Shouldn't happen, but just in case...
if (earlyException != null) {
throw earlyException;
}
if (value.equals("true")) {
return trueInstance;
}
if (value.equals("false")) {
return falseInstance;
}
if (value.equals("")) {
return invalidInstance;
}
throw new ParsingException("Boolean string must be true or false");
}
/**
* Returns a <code>BooleanAttribute</code> that represents
* the boolean value provided.
*
* @param value a boolean representing the desired value
* @return a <code>BooleanAttribute</code> representing the
* appropriate value
*/
public static BooleanAttribute getInstance(boolean value) {
// Shouldn't happen, but just in case...
if (earlyException != null) {
throw earlyException;
}
if (value) {
return trueInstance;
}
return falseInstance;
}
/**
* Returns a <code>BooleanAttribute</code> that represents
* a true value.
*
* @return a <code>BooleanAttribute</code> representing a
* true value
*/
public static BooleanAttribute getTrueInstance() {
// Shouldn't happen, but just in case...
if (earlyException != null) {
throw earlyException;
}
return trueInstance;
}
/**
* Returns a <code>BooleanAttribute</code> that represents
* a false value.
*
* @return a <code>BooleanAttribute</code> representing a
* false value
*/
public static BooleanAttribute getFalseInstance() {
// Shouldn't happen, but just in case...
if (earlyException != null) {
throw earlyException;
}
return falseInstance;
}
/**
* Returns the <code>boolean</code> value represented by this object.
*
* @return the <code>boolean</code> value
*/
public boolean getValue() {
if (!valid) {
throw new RuntimeException("Accessing invalid attribute");
}
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 BooleanAttribute)) {
return false;
}
BooleanAttribute other = (BooleanAttribute)o;
return (this.value == other.value && this.valid == other.valid);
}
/**
* 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() {
// these numbers come from the javadoc for java.lang.Boolean...no,
// really, they do. I can't imagine what they were thinking...
return (this.value ? 1231 : 1237);
}
/**
* @return The String encoding this AttributeValue.
*/
public String encode() {
if (valid ) {
return (this.value ? "true" : "false");
} else {
return "";
}
}
}