001/**
002 *
003 * Copyright 2018-2021 Florian Schmaus
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.jivesoftware.smack.fsm;
018
019import java.io.IOException;
020
021import org.jivesoftware.smack.SmackException;
022import org.jivesoftware.smack.XMPPException;
023import org.jivesoftware.smack.c2s.XmppClientToServerTransport;
024import org.jivesoftware.smack.c2s.internal.ModularXmppClientToServerConnectionInternal;
025import org.jivesoftware.smack.c2s.internal.WalkStateGraphContext;
026
027/**
028 * Note that this is an non-static inner class of XmppClientToServerConnection so that states can inspect and modify
029 * the connection.
030 */
031public abstract class State {
032
033    protected final StateDescriptor stateDescriptor;
034
035    protected final ModularXmppClientToServerConnectionInternal connectionInternal;
036
037    protected State(StateDescriptor stateDescriptor, ModularXmppClientToServerConnectionInternal connectionInternal) {
038        this.stateDescriptor = stateDescriptor;
039        this.connectionInternal = connectionInternal;
040    }
041
042    /**
043     * Check if the state should be activated.
044     *
045     * @param walkStateGraphContext the context of the current state graph walk.
046     * @return <code>null</code> if the state should be activated.
047     * @throws SmackException in case a Smack exception occurs.
048     */
049    public StateTransitionResult.TransitionImpossible isTransitionToPossible(WalkStateGraphContext walkStateGraphContext)
050                    throws SmackException {
051        return null;
052    }
053
054    public abstract StateTransitionResult.AttemptResult transitionInto(WalkStateGraphContext walkStateGraphContext)
055                    throws IOException, SmackException, InterruptedException, XMPPException;
056
057    public StateDescriptor getStateDescriptor() {
058        return stateDescriptor;
059    }
060
061    public void resetState() {
062    }
063
064    @Override
065    public String toString() {
066        return "State " + stateDescriptor + ' ' + connectionInternal.connection;
067    }
068
069    protected final void ensureNotOnOurWayToAuthenticatedAndResourceBound(
070                    WalkStateGraphContext walkStateGraphContext) {
071        if (walkStateGraphContext.isFinalStateAuthenticatedAndResourceBound()) {
072            throw new IllegalStateException(
073                            "Smack should never attempt to reach the authenticated and resource bound state over "
074                                            + this
075                                            + ". This is probably a programming error within Smack, please report it to the develoeprs.");
076        }
077    }
078
079    public abstract static class AbstractTransport extends State {
080
081        private final XmppClientToServerTransport transport;
082
083        protected AbstractTransport(XmppClientToServerTransport transport, StateDescriptor stateDescriptor,
084                        ModularXmppClientToServerConnectionInternal connectionInternal) {
085            super(stateDescriptor, connectionInternal);
086            this.transport = transport;
087        }
088
089        @Override
090        public StateTransitionResult.TransitionImpossible isTransitionToPossible(WalkStateGraphContext walkStateGraphContext)
091                        throws SmackException {
092            if (!transport.hasUseableConnectionEndpoints()) {
093                return new StateTransitionResult.TransitionImpossibleBecauseNoEndpointsDiscovered(transport);
094            }
095
096            return super.isTransitionToPossible(walkStateGraphContext);
097        }
098    }
099}