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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2018 Ericsson. All rights reserved.
* Modifications Copyright (C) 2021 Bell Canada. 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.examples.servlet;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
import org.onap.policy.apex.model.basicmodel.concepts.ApexRuntimeException;
import org.onap.policy.apex.service.engine.main.ApexMain;
import org.slf4j.ext.XLogger;
import org.slf4j.ext.XLoggerFactory;
/**
* This class is a listener that is called when the servlet is started and stopped. It brings up the Apex engine on
* servlet start and shuts it down on servlet stop.
*
* @author Liam Fallon (liam.fallon@ericsson.com)
*/
@WebListener
public class ApexServletListener implements ServletContextListener {
private static final XLogger LOGGER = XLoggerFactory.getXLogger(ApexServletListener.class);
// The Apex engine reference
private ApexMain apexMain;
/**
* {@inheritDoc}.
*/
@Override
public void contextInitialized(final ServletContextEvent servletContextEvent) {
// The web.xml file contains the context parameters for the Apex engine
final String configFileName = servletContextEvent.getServletContext().getInitParameter("config-file");
final String modelFileName = servletContextEvent.getServletContext().getInitParameter("model-file");
LOGGER.info("Apex Servliet has been started, config-file={}, model-file={}", configFileName, modelFileName);
// Check that a configuration file have been specified
if (servletContextEvent.getServletContext().getInitParameter("config-file") == null) {
final String errorMessage =
"Apex servlet start failed, servlet parameter \"config-file\" has not been specified";
LOGGER.error("Apex servlet start failed, servlet parameter \"config-file\" has not been specified");
throw new ApexRuntimeException(errorMessage);
}
// Construct the Apex command line arguments
final List<String> argsList = new ArrayList<>();
argsList.add("-config-file");
argsList.add(configFileName);
// Model file name is an optional parameter
if (modelFileName != null) {
argsList.add("-model-file");
argsList.add(modelFileName);
}
// Initialize apex
try {
apexMain = new ApexMain(argsList.toArray(new String[argsList.size()]));
} catch (ApexException e) {
LOGGER.error("Apex Engine initialization failed", e);
}
}
/**
* {@inheritDoc}.
*/
@Override
public void contextDestroyed(final ServletContextEvent servletContextEvent) {
// Shut Apex down
try {
apexMain.shutdown();
apexMain = null;
} catch (final ApexException e) {
final String errorMessage = "Apex servlet stop did not execute normally";
LOGGER.error(errorMessage, e);
}
LOGGER.info("Apex Servliet has been stopped");
}
}
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