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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 *    Copyright (c) [2018] Payara Foundation and/or its affiliates. All rights reserved.
 * 
 *     The contents of this file are subject to the terms of either the GNU
 *     General Public License Version 2 only ("GPL") or the Common Development
 *     and Distribution License("CDDL") (collectively, the "License").  You
 *     may not use this file except in compliance with the License.  You can
 *     obtain a copy of the License at
 *     https://github.com/payara/Payara/blob/master/LICENSE.txt
 *     See the License for the specific
 *     language governing permissions and limitations under the License.
 * 
 *     When distributing the software, include this License Header Notice in each
 *     file and include the License file at glassfish/legal/LICENSE.txt.
 * 
 *     GPL Classpath Exception:
 *     The Payara Foundation designates this particular file as subject to the "Classpath"
 *     exception as provided by the Payara Foundation in the GPL Version 2 section of the License
 *     file that accompanied this code.
 * 
 *     Modifications:
 *     If applicable, add the following below the License Header, with the fields
 *     enclosed by brackets [] replaced by your own identifying information:
 *     "Portions Copyright [year] [name of copyright owner]"
 * 
 *     Contributor(s):
 *     If you wish your version of this file to be governed by only the CDDL or
 *     only the GPL Version 2, indicate your decision by adding "[Contributor]
 *     elects to include this software in this distribution under the [CDDL or GPL
 *     Version 2] license."  If you don't indicate a single choice of license, a
 *     recipient has the option to distribute your version of this file under
 *     either the CDDL, the GPL Version 2 or to extend the choice of license to
 *     its licensees as provided above.  However, if you add GPL Version 2 code
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 *     only if the new code is made subject to such option by the copyright
 *     holder.
 */

package fish.payara.microprofile.metrics.rest;

import static fish.payara.microprofile.metrics.Constants.ENDPOINT_PATTERN;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.servlet.ServletContainerInitializer;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

public class MetricsServletContainerInitializer implements ServletContainerInitializer {

    @Override
    public void onStartup(Set> set, ServletContext ctx) throws ServletException {  
        
        if(!"".equals(ctx.getContextPath())){
            return;
        }
        
        // Check if there is already a servlet for metrics
        Map registrations = ctx.getServletRegistrations();
        for (ServletRegistration reg : registrations.values()) {
            if (reg.getClass().equals(MetricsResource.class)) {
                return;
            }
        }

        // Collect the url pattern for metrics handlers
        List urlPatternList = new ArrayList<>();
        urlPatternList.add(ENDPOINT_PATTERN);

        // Register a servlet with url patterns of metrics handlers
        if (!urlPatternList.isEmpty()) {
            ServletRegistration.Dynamic reg = ctx.addServlet("microprofile-metrics-resource", MetricsResource.class);
            reg.addMapping(urlPatternList.toArray(new String[urlPatternList.size()]));
        }
    }
}