2 * ============LICENSE_START=======================================================
3 * Copyright (C) 2016-2018 Ericsson. All rights reserved.
4 * ================================================================================
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
17 * SPDX-License-Identifier: Apache-2.0
18 * ============LICENSE_END=========================================================
21 package org.onap.policy.apex.core.infrastructure.messaging.impl.ws.client;
25 import org.java_websocket.WebSocket;
26 import org.onap.policy.apex.core.infrastructure.messaging.MessageHolder;
27 import org.onap.policy.apex.core.infrastructure.messaging.MessagingService;
28 import org.onap.policy.apex.core.infrastructure.messaging.util.MessagingUtils;
29 import org.onap.policy.apex.core.infrastructure.threading.ThreadUtilities;
32 * The Class MessagingClient is the class that wraps web socket handling, message sending, and
33 * message reception on the client side of a web socket in Apex.
35 * @author Sajeevan Achuthan (sajeevan.achuthan@ericsson.com)
36 * @param <M> the generic type
38 public class MessagingClient<M> extends InternalMessageBusClient<M> implements MessagingService<M> {
39 // The length of time to wait for a connection to a web socket server before aborting
40 private static final int CONNECTION_TIMEOUT_TIME_MS = 3000;
42 // The length of time to wait before checking if a connection to a web socket server has worked
44 private static final int CONNECTION_TRY_INTERVAL_MS = 100;
47 * Constructor of this class, uses its {@link InternalMessageBusClient} superclass to set up the
48 * web socket and handle incoming message forwarding.
50 * @param serverUri The URI of the service
52 public MessagingClient(final URI serverUri) {
53 // Call the super class to create the web socket and set up received message forwarding
61 public void stopConnection() {
62 // Stop message reception in the super class
65 // Close the web socket
66 final WebSocket connection = super.getConnection();
67 if (connection != null && connection.isOpen()) {
68 connection.closeConnection(0, "");
77 public void startConnection() {
78 // Open the web socket
79 final WebSocket connection = super.getConnection();
81 if (connection == null) {
82 throw new IllegalStateException("Could not connect to the server");
84 if (!connection.isOpen()) {
88 if (!waitforConnection(connection)) {
89 throw new IllegalStateException("Could not connect to the server");
94 * This method waits for the timeout value for the client to connect to the web socket server.
96 * @param connection the connection to wait on
97 * @return true, if successful
99 private boolean waitforConnection(final WebSocket connection) {
100 // The total time we have before timeout
101 int timeoutMsCounter = CONNECTION_TIMEOUT_TIME_MS;
103 // Check the connection state
105 switch (connection.getReadyState()) {
106 case NOT_YET_CONNECTED:
109 // Not connected yet so wait for the try interval
110 ThreadUtilities.sleep(CONNECTION_TRY_INTERVAL_MS);
111 timeoutMsCounter -= CONNECTION_TRY_INTERVAL_MS;
114 // Connection is open, happy days
117 // Connection is closed, bah
123 // While the timeout value has not expired
124 while (timeoutMsCounter > 0);
134 public void send(final MessageHolder<M> commands) {
135 // Get the connection and send the message
136 final WebSocket connection = super.getConnection();
137 connection.send(MessagingUtils.serializeObject(commands));
144 public void send(final String messageString) {
145 final WebSocket connection = super.getConnection();
146 connection.send(messageString);
153 public boolean isStarted() {
154 return getConnection().isOpen();