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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2016-2018 Ericsson. All rights reserved.
* ================================================================================
* Licensed 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.
*
* SPDX-License-Identifier: Apache-2.0
* ============LICENSE_END=========================================================
*/
package org.onap.policy.apex.core.infrastructure.messaging.impl.ws.client;
import java.net.URI;
import org.java_websocket.WebSocket;
import org.onap.policy.apex.core.infrastructure.messaging.MessageHolder;
import org.onap.policy.apex.core.infrastructure.messaging.MessagingService;
import org.onap.policy.apex.core.infrastructure.messaging.util.MessagingUtils;
import org.onap.policy.apex.core.infrastructure.threading.ThreadUtilities;
/**
* The Class MessagingClient is the class that wraps web socket handling, message sending, and
* message reception on the client side of a web socket in Apex.
*
* @author Sajeevan Achuthan (sajeevan.achuthan@ericsson.com)
* @param <MESSAGE> the generic type
*/
public class MessagingClient<MESSAGE> extends InternalMessageBusClient<MESSAGE> implements MessagingService<MESSAGE> {
// The length of time to wait for a connection to a web socket server before aborting
private static final int CONNECTION_TIMEOUT_TIME_MS = 3000;
// The length of time to wait before checking if a connection to a web socket server has worked
// or not
private static final int CONNECTION_TRY_INTERVAL_MS = 100;
/**
* Constructor of this class, uses its {@link InternalMessageBusClient} superclass to set up the
* web socket and handle incoming message forwarding.
*
* @param serverUri The URI of the service
*/
public MessagingClient(final URI serverUri) {
// Call the super class to create the web socket and set up received message forwarding
super(serverUri);
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.core.infrastructure.messaging.MessagingService#stopConnection()
*/
@Override
public void stopConnection() {
// Stop message reception in the super class
super.stopListener();
// Close the web socket
final WebSocket connection = super.getConnection();
if (connection != null && connection.isOpen()) {
connection.closeConnection(0, "");
}
this.close();
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.core.infrastructure.messaging.MessagingService#startConnection()
*/
@Override
public void startConnection() {
// Open the web socket
final WebSocket connection = super.getConnection();
if (connection == null) {
throw new IllegalStateException("Could not connect to the server");
}
if (!connection.isOpen()) {
connect();
}
if (!waitforConnection(connection)) {
throw new IllegalStateException("Could not connect to the server");
}
}
/**
* This method waits for the timeout value for the client to connect to the web socket server.
*
* @param connection the connection to wait on
* @return true, if successful
*/
private boolean waitforConnection(final WebSocket connection) {
// The total time we have before timeout
int timeoutMSCounter = CONNECTION_TIMEOUT_TIME_MS;
// Check the connection state
do {
switch (connection.getReadyState()) {
case NOT_YET_CONNECTED:
case CONNECTING:
case CLOSING:
// Not connected yet so wait for the try interval
ThreadUtilities.sleep(CONNECTION_TRY_INTERVAL_MS);
timeoutMSCounter -= CONNECTION_TRY_INTERVAL_MS;
break;
case OPEN:
// Connection is open, happy days
return true;
case CLOSED:
// Connection is closed, bah
return false;
default:
break;
}
}
// While the timeout value has not expired
while (timeoutMSCounter > 0);
// We have timed out
return false;
}
/*
* (non-Javadoc)
*
* @see
* org.onap.policy.apex.core.infrastructure.messaging.MessagingService#send(org.onap.policy.apex
* .core. infrastructure. messaging.MessageHolder)
*/
@Override
public void send(final MessageHolder<MESSAGE> commands) {
// Get the connection and send the message
final WebSocket connection = super.getConnection();
connection.send(MessagingUtils.serializeObject(commands));
}
/*
* (non-Javadoc)
*
* @see
* org.onap.policy.apex.core.infrastructure.messaging.MessagingService#send(java.lang.String)
*/
@Override
public void send(final String messageString) {
final WebSocket connection = super.getConnection();
connection.send(messageString);
}
/*
* (non-Javadoc)
*
* @see org.onap.policy.apex.core.infrastructure.messaging.MessagingService#isStarted()
*/
@Override
public boolean isStarted() {
return getConnection().isOpen();
}
}
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