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/*
* 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.tuscany.sca.guardian;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Stack;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.osoa.sca.annotations.Init;
import org.osoa.sca.annotations.Reference;
import org.osoa.sca.annotations.Scope;
import org.osoa.sca.annotations.Destroy;
@Scope("COMPOSITE")
public class GuardianMemberImpl implements GuardianMember {
private Stack<Context> contextList;
private BlockingInterface service;
private Queue<GlobalException> exceptionQueue;
@Reference(name = "guardian_group", required = true)
public GuardianGroup guardianGroup;
private int id;
public GuardianMemberImpl() {
contextList = new Stack<Context>();
exceptionQueue = new LinkedList<GlobalException>();
}
@Init
public void init() {
guardianGroup.addGuardianMember(this);
}
@Destroy
public void destroy() {
guardianGroup.removeGuardianMember(this);
}
public void addException(GlobalException ex) {
exceptionQueue.add(ex);
}
public void setService(BlockingInterface service) {
this.service = service;
}
public Context getCurrentContext() {
return contextList.peek();
}
public BlockingInterface getService() {
return service;
}
public void enableContext(Context context) {
//Update the context list with the related set of exceptions
contextList.push(context);
if (contextList.size() == 1) {
gthrow(new JoinException(), null);
}
}
public void removeContext() {
if (!contextList.isEmpty()) {
contextList.pop();
}
}
//Adapt to allow a regular expression
//If participantList is null then signal to ALL participants
public void gthrow(GlobalException ex, List<String> participantList) {
//1)Block the participant until raise an exception
if (!service.isBlocked()) {
service.block();
if (ex != null) {
//Set the exception's parameters
ex.setSignalingContext(getCurrentContext());
ex.setSignalingParticipant(getParticipantIdentifier());
guardianGroup.gthrow(ex, participantList);
}
//if (participantList == null || !participantList.contains(getParticipantIdentifier())) {
// if (getParticipantIdentifier().equals(ex.getSignalingParticipant())) {
// //2A)Call the gthrow of the GuardianGroup - communicate with other guardian members
// System.out.println("HERE AT " + getParticipantIdentifier());
// guardianGroup.gthrow(ex, participantList);
// }
}
//*Is here the best place to receive such kind of msg?
//
//2B)When receive exception_msg from GuardianGroup do
// if participant is not suspended then suspend it
// if participant supports interrupts then
// interrupt it, add SuspendException in the exception_queue, and invoke checkExceptionStatus
// else invoke checkExceptionStatus periodically
//
//4)Once ALL required participants are SUSPENDED (suspended point), invoke the defined Recovery Rules
// 4.1) recovery_rules < signaled exceptions + context_list of all participant > target context + exception to raise
// 4.2) raise the resolved exception in each participant -> it goes to the exception_queue
}
public boolean propagate(GlobalException ex) {
//1)Compares the current context with the exception's target context
return !getCurrentContext().equals(ex.getTargetContext());
}
public void checkExceptionStatus() throws GlobalException {
//1)Chek the exception queue
// 1.1) if exception_queue is empty then return
// else if first element on the exception_queue is SuspendException then
// the method blocks until the next exception is received. The method raises the first non-SuspendException in the queue
GlobalException exc;
if ((exc = exceptionQueue.peek()) == null) {
System.out.println(getParticipantIdentifier() + "#No exception on exception queue");
return;
} else {
while ((exc = exceptionQueue.peek()) instanceof SuspendException) {
try {
Thread.sleep(5000);
} catch (InterruptedException ex) {
Logger.getLogger(GuardianMemberImpl.class.getName()).log(Level.SEVERE, null, ex);
}
exceptionQueue.poll();
}
service.unblock();
// if (exc != null) {
// System.out.println("\n" + getParticipantIdentifier() + "#");
// System.out.println("Exc: " + exc);
// System.out.println("TargetContext: " + exc.getTargetContext().getName());
// System.out.println("Signaling Participant: " + exc.getSignalingParticipant());
// System.out.println("Current Context: " + getCurrentContext().getName());
// System.out.println("Equals: " + exc.getTargetContext().equals(getCurrentContext()) + "\n");
// }
//FIX-ME: ex.targetContext() matches the participant id -> could use regular expressions
//Eg. ex.targetContext(): Main and participant id: Init/Main/Backup -> should throw the exception
String[] contexts = getParticipantIdentifier().split("\\.");
if (exc != null) {
for (int i = contexts.length - 1; i > 0; i--) {
if (exc.getTargetContext().equals(new Context(contexts[i]))) {
System.out.println(getParticipantIdentifier() + "#Returning an exception");
exceptionQueue.poll();
throw exc;
}
}
}
// if (exc != null && exc.getTargetContext().equals(getCurrentContext())) {
// System.out.println(getParticipantIdentifier() + "#Returning an exception");
// exceptionQueue.poll();
// throw exc;
// }
return;
}
}
public String getParticipantIdentifier() {
//1) Return the participant identifier -> context list dot separated
StringBuffer id = new StringBuffer();
id.append(this.id + "." + Context.INIT_CONTEXT.getName());
for (int i = 0; i < contextList.size(); i++) {
id.append("." + contextList.get(i).getName());
// if (i + 1 != contextList.size()) {
// id.append(".");
// }
}
return id.toString();
}
public void setUniqueParticipantID(int id) {
this.id = id;
}
public void removeService() {
this.service = null;
}
}
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