001 /*
002 * Copyright (c) 2005-2006 Stephen J. McConnell
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
013 * implied.
014 *
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package net.dpml.component;
020
021 import java.io.IOException;
022 import java.lang.reflect.InvocationTargetException;
023 import java.rmi.Remote;
024 import java.rmi.RemoteException;
025
026 /**
027 * The Component represents a remote interface to a runtime component type.
028 *
029 * @author <a href="http://www.dpml.net">Digital Product Meta Library</a>
030 * @version 1.0.4
031 */
032 public interface Component extends Remote, Commissionable
033 {
034 /**
035 * Return a provider of an instance of the component.
036 * @return the instance provider
037 * @exception InvocationTargetException if a target invocation error occurs
038 * @exception IOException if a IO error occurs
039 * @exception InvocationTargetException if a component invocation error occurs
040 */
041 Provider getProvider() throws IOException, InvocationTargetException;
042
043 /**
044 * Return true if this handler is a candidate for the supplied service definition.
045 * @param service the service descriptor
046 * @return true if this is a candidate
047 * @exception RemoteException if a remote exception occurs
048 */
049 boolean isaCandidate( Service service ) throws RemoteException;
050
051 /**
052 * Get the activation policy. If the activation policy is STARTUP, an implementation
053 * a handler shall immidiately activation a runtime instance. If the policy is on DEMAND
054 * an implementation shall defer activiation until an explicit request is received. If
055 * the policy if SYSTEM activation may occur at the discretion of an implementation.
056 *
057 * @return the activation policy
058 * @exception RemoteException if a remote exception occurs
059 * @see ActivationPolicy#SYSTEM
060 * @see ActivationPolicy#STARTUP
061 * @see ActivationPolicy#DEMAND
062 */
063 ActivationPolicy getActivationPolicy() throws RemoteException;
064
065 /**
066 * Returns the commissioned status of the handler.
067 * @return TRUE if the handler has been commissioned otherwise FALSE
068 * @exception RemoteException if a remote exception occurs
069 */
070 boolean isActive() throws RemoteException;
071
072 /**
073 * Return the number of instances currently under management.
074 * @return the instance count.
075 * @exception RemoteException if a remote exception occurs
076 */
077 int size() throws RemoteException;
078
079 }
080