/*
* 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.platform;
import net.jxta.id.ID;
import java.net.URI;
/**
* A ModuleClassID uniquely identifies a particular local behaviour, that is,
* a specific API for each execution environment for which an implementation
* exists.
*
* <p/>A ModuleClassID has two components: A base class identifier, and a role identifier.
* The role identifier may be zero. By convention the API uses the ModuleClassID with
* a zero role identifier to designate the base class in contexts where only the base class
* is significant. Nonetheless, a ModuleClassID with a zero role identifier is a valid
* ModulesClassID wherever a full ModuleClassID is expected. In many cases, only one role
* in a given class is ever used. Using role zero in such cases is an optimization because
* it may make the string representation of the ModuleClassID shorter.
*
* <p/>Each service of a group, that is, the role it plays in the group, is uniquely identified
* per the group definition.
* This identifier may be used by other modules in the group to designate this one, or by the service
* itself to identify its parameters in a PeerAdvertisement. In addition, by combining its
* PeerGroupID with its own ModuleClassID, a service may create a predictible identifier unique
* on their peer, suitable for registering listeners with the EndpointService or other services
* with similar listener interfaces.
*
* <p/>The standard PeerGroup implementation of the java reference implementation
* assigns to each service its ModuleClassID as its unique service identifier. Most of the
* times this ModuleClassID is a base classID, but groups that use the same Module Class
* for more than one service (same behaviour but playing a different role in the group, such
* as, for example, a data base engine with a different data base), may define multiple roles
* identified by the same base class identifier but different role identifiers. The standard
* PeerGroup implementation of the java reference implementation has the notion of main
* application: a default application which may be started automatically upon instantiating
* the group. This application implements Module and, therefore, is assigned a ModuleClassID.
* However applications are not expected to play any specific role in the group. As a result, they
* are assigned a role identifier allocated at run-time as need to garantee local unicity. As
* a result main applications cannot expect a predictible ClassID.
*
* <p/>A ModuleClassID is optionaly described by a published ModuleClassAdvertisement.
*
* <p/>There may be any number of embodiements of a module class. These are module
* specifications. A module specification represent the network behaviour of a
* module while its class represents its local behaviour. Different groups
* may use a common subset of classes, for example, the basic set defined by the platform
* should always be part of it. Each group may use different and network-incompatible
* specifications for common classes, optimized for various purposes. The local API of a
* given class on a given JXTA implementation will be invariant per the spec being used.
* Therefore, the difference will be transparent to applications which do not depend
* on the possibly different quality of service.
*
* <p/>A ModuleSpecID embeds a base class identifier, which permits to verify that
* a given Module specification is suitable for its intended use.
*
* @see net.jxta.peergroup.PeerGroup
* @see net.jxta.platform.Module
* @see net.jxta.platform.ModuleClassID
* @see net.jxta.protocol.PeerAdvertisement
* @see net.jxta.protocol.ModuleSpecAdvertisement
* @see net.jxta.protocol.ModuleClassAdvertisement
* @see net.jxta.endpoint.EndpointService
* @see net.jxta.id.ID
*
*/
public abstract class ModuleClassID 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 a 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 {@code fromURI} is {@code null}.
* @throws IllegalArgumentException If the given URI is not a valid ID.
*/
public static ModuleClassID create(URI fromURI) {
return (ModuleClassID) ID.create(fromURI);
}
/**
* {@inheritDoc}
*/
public ModuleClassID intern() {
return (ModuleClassID) super.intern();
}
/**
* Returns true if this ModuleClassID is of the same base class than the
* given class.
* Note: This method is NOT named "isOfClass" because a ModuleClassID
* may have two UUID; one that denotes a "base" class proper,
* and an optional second one that denotes a "Role", or subclass.
* Compatibility between ClassIDs is based on the "base" portion, hence the
* "isOfSame" naming. This routine can be used for comparison with a base class
* since a base class is just a class which role portion happens to be zero.
*
* @param id Module class id to compare with
* @return boolean true if equals
*/
public abstract boolean isOfSameBaseClass(ModuleClassID id);
/**
* Returns true if this ModuleClassID is of the same class than the
* the given ModuleSpecID.
*
* @param id Module spec id to compare with
* @return boolean true if equals
*/
public abstract boolean isOfSameBaseClass(ModuleSpecID id);
/**
* Return a ModuleClassID of the same base class but with the role portion
* set to zero. aka "the base class".
*
* @return ModuleClassID the base class.
*/
public abstract ModuleClassID getBaseClass();
}