/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.as.clustering.jgroups;

import java.nio.ByteBuffer;
import java.util.Objects;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.jgroups.Channel;
import org.jgroups.Event;
import org.jgroups.JChannel;
import org.jgroups.Message;
import org.jgroups.blocks.RequestCorrelator;
import org.jgroups.blocks.RequestCorrelator.Header;
import org.jgroups.conf.ClassConfigurator;
import org.jgroups.fork.UnknownForkHandler;
import org.jgroups.protocols.FORK;
import org.jgroups.stack.ProtocolStack;
import org.wildfly.clustering.jgroups.spi.ChannelFactory;
import org.wildfly.clustering.jgroups.spi.ProtocolStackConfiguration;
import org.wildfly.clustering.jgroups.spi.TransportConfiguration;

/**
 * Factory for creating fork-able channels.
 * @author Paul Ferraro
 */
public class JChannelFactory implements ChannelFactory {

    static final ByteBuffer UNKNOWN_FORK_RESPONSE = ByteBuffer.allocate(0);

    private final ProtocolStackConfiguration configuration;

    public JChannelFactory(ProtocolStackConfiguration configuration) {
        this.configuration = configuration;
    }

    @Override
    public ProtocolStackConfiguration getProtocolStackConfiguration() {
        return this.configuration;
    }

    @Override
    public Channel createChannel(String id) throws Exception {
        JChannel channel = new JChannel(false);
        ProtocolStack stack = new ProtocolStack();
        channel.setProtocolStack(stack);
        stack.addProtocols(Stream.of(
                Stream.of(this.configuration.getTransport()),
                this.configuration.getProtocols().stream(),
                Stream.of(this.configuration.getRelay())
        ).flatMap(Function.identity()).filter(Objects::nonNull).map(pc -> pc.createProtocol(this.configuration)).collect(Collectors.toList()));

        // Add implicit FORK to the top of the stack
        FORK fork = new FORK();
        fork.enableStats(this.configuration.isStatisticsEnabled());
        fork.setUnknownForkHandler(new UnknownForkHandler() {
            private final short id = ClassConfigurator.getProtocolId(RequestCorrelator.class);

            @Override
            public Object handleUnknownForkStack(Message message, String forkStackId) {
                return this.handle(message);
            }

            @Override
            public Object handleUnknownForkChannel(Message message, String forkChannelId) {
                return this.handle(message);
            }

            private Object handle(Message message) {
                Header header = (Header) message.getHeader(this.id);
                // If this is a request expecting a response, don't leave the requester hanging - send an identifiable response on which it can filter
                if ((header != null) && (header.type == Header.REQ) && header.rspExpected()) {
                    Message response = message.makeReply().setFlag(message.getFlags()).clearFlag(Message.Flag.RSVP, Message.Flag.SCOPED);

                    response.putHeader(FORK.ID, message.getHeader(FORK.ID));
                    response.putHeader(this.id, new Header(Header.RSP, header.req_id, header.corrId));
                    response.setBuffer(UNKNOWN_FORK_RESPONSE.array());

                    channel.down(new Event(Event.MSG, response));
                }
                return null;
            }
        });
        stack.addProtocol(fork);
        stack.init();

        channel.setName(this.configuration.getNodeName());

        TransportConfiguration.Topology topology = this.configuration.getTransport().getTopology();
        if (topology != null) {
            channel.addAddressGenerator(new TopologyAddressGenerator(topology));
        }

        return channel;
    }

    @Override
    public boolean isUnknownForkResponse(ByteBuffer response) {
        return UNKNOWN_FORK_RESPONSE.equals(response);
    }
}

@@ -1108,50 +1108,15 @@
 il.O
-bjects;%0Aimport java.util.function.Function
+ptional
 ;%0Aim
@@ -1545,21 +1545,16 @@
 Protocol
-Stack
 ;%0Aimport
@@ -1605,16 +1605,81 @@
 actory;%0A
+import org.wildfly.clustering.jgroups.spi.ProtocolConfiguration;%0A
 import o
@@ -1732,32 +1732,94 @@
 kConfiguration;%0A
+import org.wildfly.clustering.jgroups.spi.RelayConfiguration;%0A
 import org.wildf
@@ -2472,563 +2472,8 @@
 n %7B%0A
-        JChannel channel = new JChannel(false);%0A        ProtocolStack stack = new ProtocolStack();%0A        channel.setProtocolStack(stack);%0A        stack.addProtocols(Stream.of(%0A                Stream.of(this.configuration.getTransport()),%0A                this.configuration.getProtocols().stream(),%0A                Stream.of(this.configuration.getRelay())%0A        ).flatMap(Function.identity()).filter(Objects::nonNull).map(pc -%3E pc.createProtocol(this.configuration)).collect(Collectors.toList()));%0A%0A        // Add implicit FORK to the top of the stack%0A
     
@@ -3849,23 +3849,52 @@
         
-c
+fork.getProtocolStack().getC
 hannel
+()
 .down(ne
@@ -3997,24 +3997,25 @@
     %7D);%0A
+%0A
         
 stack.ad
@@ -4010,41 +4010,573 @@
     
-stack.addProtocol(fork
+// Transport always resides at the bottom of the stack%0A        Stream%3CProtocolConfiguration%3C?%3E%3E protocolConfigs = Stream.concat(Stream.of(this.configuration.getTransport()), this.configuration.getProtocols().stream());%0A        Stream%3CRelayConfiguration%3E relayConfig = Optional.ofNullable(this.configuration.getRelay()).map(Stream::of).orElse(Stream.empty());%0A        // Add RELAY2 to the top of the stack, if defined%0A        Stream%3CProtocol%3E protocols = Stream.concat(protocolConfigs, relayConfig).map(config -%3E config.createProtocol(this.configuration)
 );%0A
+%0A
         
 stac
@@ -4575,19 +4575,163 @@
     
-stack.init(
+// Add implicit FORK to the top of the stack%0A        JChannel channel = new JChannel(Stream.concat(protocols, Stream.of(fork)).collect(Collectors.toList())
 );%0A%0A

Simplify JChannel construction. Reduce array allocations when building protocol list.