/*
* Copyright (c) 2001-2007 Sun Microsystems, Inc. All rights reserved.
*
* The Sun Project JXTA(TM) Software License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions 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.
*
* 3. The end-user documentation included with the redistribution, if any, must
* include the following acknowledgment: "This product includes software
* developed by Sun Microsystems, Inc. for JXTA(TM) technology."
* Alternately, this acknowledgment may appear in the software itself, if
* and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
* not be used to endorse or promote products derived from this software
* without prior written permission. For written permission, please contact
* Project JXTA at http://www.jxta.org.
*
* 5. Products derived from this software may not be called "JXTA", nor may
* "JXTA" appear in their name, without prior written permission of Sun.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SUN
* MICROSYSTEMS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* JXTA is a registered trademark of Sun Microsystems, Inc. in the United
* States and other countries.
*
* Please see the license information page at :
* <http://www.jxta.org/project/www/license.html> for instructions on use of
* the license in source files.
*
* ====================================================================
*
* This software consists of voluntary contributions made by many individuals
* on behalf of Project JXTA. For more information on Project JXTA, please see
* http://www.jxta.org.
*
* This license is based on the BSD license adopted by the Apache Foundation.
*/
package net.jxta.content;
import java.net.URI;
import net.jxta.id.ID;
/**
* An identifier that enables canonical references to be made to a Content
* instance within the context of a specific peer group.
* <p/>
* <p/>A ContentID is formed by the conjuction of:<ul>
* <li>a PeerGroupID</li>
* <li>a randomly chosen value that has a high probability of being unique</li>
* <li>an optional SHA1 cryptographic hash of the Content contents</li></ul>
* <p/>
* <p/>Content which contain static content will normally include the hash value
* as part of their ContentID.
*
* @see net.jxta.content.Content
* @see net.jxta.peergroup.PeerGroupID
*/
public abstract class ContentID extends ID {
/**
*
* Creates an ID by parsing the given URI.
*
* <p>This convenience factory method works as if by invoking the
* {@link net.jxta.id.IDFactory#fromURI(URI)} method; any
* {@link java.net.URISyntaxException}
* thrown is caught and wrapped in a new {@link IllegalArgumentException}
* object, which is then thrown.
*
* <p> This method is provided for use in situations where it is known that
* the given string is a legal ID, for example for ID constants declared
* within in a program, and so it would be considered a programming error
* for the URI not to parse as such. The {@link net.jxta.id.IDFactory},
* which throws {@link java.net.URISyntaxException} directly, should be
* used situations where an ID is being constructed from user input or from
* some other source that may be prone to errors.
*
* @param fromURI The URI to be parsed into an ID
* @return The new ID
*
* @throws NullPointerException
* If <tt>fromURI</tt> is <tt>null</tt>
*
* @throws IllegalArgumentException
* If the given URI is not a valid ID.
*/
public static ContentID create( URI fromURI ) {
return (ContentID) ID.create(fromURI);
}
/**
* {@inheritDoc}
*/
public ContentID intern() {
return (ContentID) super.intern();
}
/**
* Returns an object containing the value of the variant portion of
* this ID. This object must provide implementations of toString(),
* equals() and hashCode() that are canonical and consistent from
* run-to-run given the same input values. Beyond this nothing should
* be assumed about the nature of this object.
*
* @return Object which can provide canonical representations of the
* variant value
*/
public abstract Object getVariantValue() ;
/**
* Returns PeerGroupID of the Peer Group to which this Content ID belongs.
*
* @return PeerGroupID of the Peer Group which this ID is part of.
*/
public abstract ID getPeerGroupID();
/**
* Returns <tt>true</tt> if this ContentID is associated with a static
* Content.
*
* @return <tt>true</tt> if the contentId is for a Content instance with
* static content, otherwise <tt>false</tt>.
*/
public abstract boolean isStatic();
}