/*
 * @(#)URISyntax.java	1.3 01/12/03
 *
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */


package javax.print.attribute;

import java.io.Serializable;
import java.net.URI;
import java.net.URISyntaxException;

/**
 * Class URISyntax is an abstract base class providing the common
 * implementation of all attributes whose value is a Uniform Resource
 * Identifier (URI). Once constructed, a URI attribute's value is immutable. 
 * <P>
 *
 * @author  Alan Kaminsky
 */
public abstract class URISyntax	implements Serializable, Cloneable {

    /**
     * URI value of this URI attribute.
     * @serial
     */
    private URI uri;

    /**
     * Constructs a URI attribute with the specified URI. 
     *
     * @param  uri  URI.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>uri</CODE> is null.
     */
    protected URISyntax(URI uri) {
	this.uri = verify (uri);
    }

    private static URI verify(URI uri) {
	if (uri == null) {
	    throw new NullPointerException(" uri is null");
	}
	return uri;
    }

    /**
     * Returns this URI attribute's URI value.
     * @return the URI.
     */
    public URI getURI()  {
	return uri;
    }

    /**
     * Returns a hashcode for this URI attribute.
     *
     * @return  A hashcode value for this object.
     */
    public int hashCode() {
	return uri.hashCode();
    }

    /**
     * Returns whether this URI attribute is equivalent to the passed in
     * object. 
     * To be equivalent, all of the following conditions must be true: 
     * <OL TYPE=1>
     * <LI>
     * <CODE>object</CODE> is not null.
     * <LI>
     * <CODE>object</CODE> is an instance of class URISyntax.
     * <LI>
     * This URI attribute's underlying URI and <CODE>object</CODE>'s 
     * underlying URI are equal. 
     * </OL>
     *
     * @param  object  Object to compare to.
     *
     * @return  True if <CODE>object</CODE> is equivalent to this URI
     *          attribute, false otherwise. 
     */
    public boolean equals(Object object) {
	return(object != null &&
	       object instanceof URISyntax &&
	       this.uri.equals (((URISyntax) object).uri));
    }
    
    /**
     * Returns a String identifying this URI attribute. The String is the
     * string representation of the attribute's underlying URI. 
     *
     * @return  A String identifying this object.
     */
    public String toString() {
	return uri.toString();
    }
    
}
