/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.axis2.clustering;
import org.apache.axis2.clustering.management.NodeManager;
import org.apache.axis2.clustering.management.GroupManagementAgent;
import org.apache.axis2.clustering.state.StateManager;
import org.apache.axis2.context.ConfigurationContext;
import org.apache.axis2.description.ParameterInclude;
import java.util.List;
import java.util.Set;
/**
* <p>
* This is the main interface in the Axis2 clustering implementation.
* In order to plug-in a new clustering implementation, this interface has to be
* implemented.
* </p>
* <p>
* The initilization of a node in the cluster is handled here. It is also responsible for getting
* this node to join the cluster. This node should not process any Web services requests until it
* successfully joins the cluster. Generally, this node will also need to obtain the state
* information and/or configuration information from a neighboring node.
* This interface is also responsible for
* properly instantiating a {@link org.apache.axis2.clustering.state.StateManager} &
* {@link org.apache.axis2.clustering.management.NodeManager}. In the case of
* a static <a href="http://blog.afkham.org/2008/05/group-membership-management-schemes.html">
* membership scheme</a>,
* this members are read from the axis2.xml file and added to the ClusteringAgent.
* </p>
* <p>
* In the axis2.xml, the instance of this interface is specified using the "clustering"
* class attribute.
* e.g.
* <code><b>
* <nobr><clustering class="org.apache.axis2.clustering.tribes.TribesClusterAgent"></nobr>
* </b>
* </code>
* specifies that the TribesClusterAgent class is the instance of this interface that
* needs to be used.
* </p>
* <p>
* There can also be several "parameter" elements, which are children of the "clustering" element
* in the axis2.xml file. Generally, these parameters will be specific to the ClusteringAgent
* implementation.
* </p>
*/
public interface ClusteringAgent extends ParameterInclude {
/**
* Initialize this node, and join the cluster
*
* @throws ClusteringFault If an error occurs while initializing this node or joining the cluster
*/
void init() throws ClusteringFault;
/**
* Do cleanup & leave the cluster
*/
void finalize();
/**
* @return The StateManager
*/
StateManager getStateManager();
/**
* @return The NodeManager
*/
NodeManager getNodeManager();
/**
* Set the StateManager corresponding to this ClusteringAgent. This is an optional attribute.
* We can have a cluster with no context replication, in which case the contextManager will be
* null. This value is set by the {@link org.apache.axis2.deployment.ClusterBuilder}, by
* reading the "contextManager" element in the axis2.xml
* <p/>
* e.g.
* <code>
* <b>
* <contextManager class="org.apache.axis2.cluster.configuration.TribesContextManager">
* </b>
* </code>
*
* @param stateManager The StateManager instance
*/
void setStateManager(StateManager stateManager);
/**
* Set the NodeManager corresponding to this ClusteringAgent. This is an optional attribute.
* We can have a cluster with no configuration management, in which case the configurationManager
* will be null. This value is set by the {@link org.apache.axis2.deployment.ClusterBuilder}, by
* reading the "configurationManager" element in the axis2.xml
* <p/>
* e.g.
* <code>
* <b>
* <configurationManager class="org.apache.axis2.cluster.configuration.TribesConfigurationManager">
* </b>
* </code>
*
* @param nodeManager The NodeManager instance
*/
void setNodeManager(NodeManager nodeManager);
/**
* Disconnect this node from the cluster. This node will no longer receive membership change
* notifications, state change messages or configuration change messages. The node will be "
* "standing alone" once it is shutdown. However, it has to continue to process Web service
* requests.
*
* @throws ClusteringFault If an error occurs while leaving the cluster
*/
void shutdown() throws ClusteringFault;
/**
* Set the system's configuration context. This will be used by the clustering implementations
* to get information about the Axis2 environment and to correspond with the Axis2 environment
*
* @param configurationContext The configuration context
*/
void setConfigurationContext(ConfigurationContext configurationContext);
/**
* Set the static members of the cluster. This is used only with
* <a href="http://blog.afkham.org/2008/05/group-membership-management-schemes.html">
* static group membership </a>
*
* @param members Members to be added
*/
void setMembers(List<Member> members);
/**
* Get the list of members in a
* <a href="http://blog.afkham.org/2008/05/group-membership-management-schemes.html">
* static group
* </a>
*
* @return The members if static group membership is used. If any other membership scheme is used,
* the values returned may not be valid
*/
List<Member> getMembers();
/**
* Get the number of members alive.
*
* @return the number of members alive.
*/
int getAliveMemberCount();
/**
* Set the load balance event handler which will be notified when load balance events occur.
* This will be valid only when this node is running in loadBalance mode
*
* @param agent The GroupManagementAgent to be added
* @param applicationDomain The application domain which is handled by the GroupManagementAgent
*/
void addGroupManagementAgent(GroupManagementAgent agent, String applicationDomain);
/**
* Add a GroupManagementAgent to an application domain + sub-domain
* @param agent The GroupManagementAgent to be added
* @param applicationDomain The application domain which is handled by the GroupManagementAgent
* @param applicationSubDomain The application sub-domain which is handled by the GroupManagementAgent
*/
void addGroupManagementAgent(GroupManagementAgent agent, String applicationDomain,
String applicationSubDomain);
/**
* Get the GroupManagementAgent which corresponds to the <code>applicationDomain</code>
* This will be valid only when this node is running in groupManagement
*
* @param applicationDomain The application domain to which the application nodes being
* load balanced belong to
* @return GroupManagementAgent which corresponds to the <code>applicationDomain</code>
*/
GroupManagementAgent getGroupManagementAgent(String applicationDomain);
/**
* Get the GroupManagementAgent which corresponds to the <code>applicationDomain + sub-domain</code>
* @param applicationDomain The application domain which is handled by the GroupManagementAgent
* @param applicationSubDomain The application sub-domain which is handled by the GroupManagementAgent
* @return GroupManagementAgent which corresponds to the <code>applicationDomain + sub-domain</code>
*/
GroupManagementAgent getGroupManagementAgent(String applicationDomain,
String applicationSubDomain);
/**
* Get all the domains that this ClusteringAgent belongs to
*
* @return the domains of this ClusteringAgent
*/
Set<String> getDomains();
/**
* Checks whether this member is the coordinator for the cluster
*
* @return true if this member is the coordinator, and false otherwise
*/
boolean isCoordinator();
/**
* Send a message to all members in this member's primary cluster
*
* @param msg The message to be sent
* @param isRpcMessage Indicates whether the message has to be sent in RPC mode
* @return A list of responses if the message is sent in RPC mode
* @throws ClusteringFault If an error occurs while sending the message
*/
List<ClusteringCommand> sendMessage(ClusteringMessage msg, boolean isRpcMessage) throws ClusteringFault;
}