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diff --git a/reference/logging-slf4j-demo/src/main/java/org/onap/logging/ref/slf4j/demo/component/AbstractComponent.java b/reference/logging-slf4j-demo/src/main/java/org/onap/logging/ref/slf4j/demo/component/AbstractComponent.java
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+++ b/reference/logging-slf4j-demo/src/main/java/org/onap/logging/ref/slf4j/demo/component/AbstractComponent.java
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+/**
+ * ============LICENSE_START=======================================================
+ * org.onap.logging
+ * ================================================================================
+ * Copyright © 2018 Amdocs
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.logging.ref.slf4j.demo.component;
+
+import java.util.Locale;
+import java.util.Map;
+import java.util.UUID;
+
+import javax.servlet.http.HttpServletRequest;
+
+import com.mashape.unirest.http.HttpResponse;
+import com.mashape.unirest.http.JsonNode;
+import com.mashape.unirest.http.Unirest;
+import com.mashape.unirest.http.exceptions.UnirestException;
+import org.apache.commons.lang3.StringUtils;
+import org.json.JSONObject;
+import org.onap.logging.ref.slf4j.ONAPLogAdapter;
+import org.onap.logging.ref.slf4j.ONAPLogConstants;
+import org.onap.logging.ref.slf4j.demo.bean.Request;
+import org.onap.logging.ref.slf4j.demo.bean.Response;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.slf4j.MDC;
+import org.springframework.http.MediaType;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Base class for <tt>Alpha</tt>, <tt>Beta</tt> and <tt>Gamma</tt>
+ * and <tt>Delta</tt> controllers, implementing all the actual logic.
+ *
+ * <p>(The subclasses provide nothing but identifiers to allow them
+ * to be distinguished from one another, for the purposes of addressing
+ * requests and generating the call graph from their logger output.)</p>
+ */
+@RestController
+public abstract class AbstractComponent {
+
+    /**
+     * Test switch, routing invocations between components in-process,
+     * rather than via REST over HTTP.
+     */
+    private static boolean sInProcess;
+
+    /**
+     * Get service identifier, used to derive {@link #getServiceName()},
+     * <tt>PartnerName</tt>, etc.
+     * @return <tt>alpha</tt>, <tt>beta</tt>, <tt>gamma</tt>.
+     */
+    protected abstract String getId();
+
+    /**
+     * Get component UUID.
+     * @return globally unique ID string.
+     */
+    protected abstract String getInstanceUUID();
+
+    /**
+     * Execute REST request.
+     * @param request request data.
+     * @param http HTTP request.
+     * @return response data.
+     * @throws UnirestException REST error.
+     */
+    @RequestMapping(value = "/invoke",
+            method = RequestMethod.POST,
+            consumes = MediaType.APPLICATION_JSON_VALUE,
+            produces = MediaType.APPLICATION_JSON_VALUE)
+    public Response execute(final Request request,
+                            final HttpServletRequest http) throws UnirestException {
+
+        final ONAPLogAdapter adapter = new ONAPLogAdapter(this.getLogger());
+
+        try {
+
+            adapter.entering(new ONAPLogAdapter.HttpServletRequestAdapter(http));
+
+            final Response response = new Response();
+            response.setService(request.getService());
+            final String code = StringUtils.defaultString(request.getCode(), "OK").toUpperCase();
+            response.setCode(this.getId() + "." + code);
+            response.setSeverity(StringUtils.defaultString(request.getSeverity(), "INFO"));
+
+            for (final Request target : request.getRequests()) {
+                final Response targetResponse = this.executeDelegate(target, http, adapter);
+                response.getResponses().add(targetResponse);
+            }
+
+            return response;
+        }
+        finally {
+            adapter.exiting();
+        }
+    }
+
+    /**
+     * Set in-process mode, for unit testing.
+     */
+    static void setInProcess() {
+        sInProcess = true;
+    }
+
+    /**
+     * Execute request.
+     * @param request to be executed.
+     * @param http incoming HTTP request.
+     * @param logger logging adapter.
+     * @return response
+     */
+    private Response executeDelegate(final Request request,
+                                     final HttpServletRequest http,
+                                     final ONAPLogAdapter logger) {
+
+
+        notNull(request);
+        notNull(http);
+
+        // Downstream call.
+
+        try {
+
+            if (sInProcess) {
+                return this.executeInProcess(request, logger);
+            }
+
+            return this.executeREST(request, http, logger);
+        }
+        catch (final UnirestException | ReflectiveOperationException e) {
+            logger.unwrap().error("Execute error", e);
+            final Response response = new Response();
+            response.setCode((this.getServiceName() + ".INVOKE_ERROR").toUpperCase(Locale.getDefault()));
+            response.setSeverity("ERROR");
+            return response;
+        }
+    }
+
+    /**
+     * Execute invocation over REST.
+     * @param request mock request to be executed.
+     * @param http HTTP request, used (only) to address the outgoing request.
+     * @param logger logger adapter.
+     * @return invocation response.
+     * @throws UnirestException REST error.
+     */
+    private Response executeREST(final Request request,
+                                 final HttpServletRequest http,
+                                 final ONAPLogAdapter logger) throws UnirestException {
+        // Otherwise via REST.
+
+        logger.unwrap().info("Sending:\n{}", request);
+        final StringBuilder url = new StringBuilder();
+        url.append(http.getProtocol()).append("://");
+        url.append(http.getServerName()).append(':');
+        url.append(http.getServerPort()).append("/services/").append(request.getService());
+
+        final UUID invocationID = logger.invoke(ONAPLogConstants.InvocationMode.SYNCHRONOUS);
+        final HttpResponse<JsonNode> response =
+                Unirest.post(url.toString())
+                        .header(ONAPLogConstants.Headers.REQUEST_ID, MDC.get(ONAPLogConstants.MDCs.REQUEST_ID))
+                        .header(ONAPLogConstants.Headers.INVOCATION_ID, invocationID.toString())
+                        .header(ONAPLogConstants.Headers.PARTNER_NAME, this.getServiceName())
+                        .header("Accept", MediaType.APPLICATION_JSON_VALUE)
+                        .header("Content-Type", MediaType.APPLICATION_JSON_VALUE)
+                        .body(request)
+                        .asJson();
+
+        // Parse response.
+
+        final JSONObject responseJSON = response.getBody().getObject();
+        logger.unwrap().info("Received:\n{}", responseJSON);
+        return Response.fromJSON(responseJSON);
+    }
+
+    /**
+     * Execute request in-process.
+     * @param request mock request to be executed.
+     * @param logger logger adapter.
+     * @return invocation response.
+     * @throws ReflectiveOperationException error loading target class.
+     * @throws UnirestException REST error.
+     */
+    private Response executeInProcess(final Request request,
+                                      final ONAPLogAdapter logger) throws ReflectiveOperationException, UnirestException {
+
+        logger.unwrap().info("Executing in-process:\n{}", request);
+
+        // Derive the name of the delegate class.
+
+        final String delegateClass
+                = AbstractComponent.class.getPackage().getName() + "." + request.getService()
+                + ".Component" + request.getService().substring(0, 1).toUpperCase()
+                + request.getService().substring(1);
+        logger.unwrap().info("Invoking in-process [{}].", delegateClass);
+        final AbstractComponent component = (AbstractComponent)Class.forName(delegateClass).newInstance();
+
+        // Using Spring mock since we're not *actually* going over HTTP.
+
+        final MockHttpServletRequest mock = new MockHttpServletRequest();
+
+        // Generate INVOCATION_ID, and set MDCs aside for safekeeping.
+        // (This is because when mocking, everything happens in the same thread.)
+
+        final UUID invocationID = logger.invoke(ONAPLogConstants.InvocationMode.SYNCHRONOUS);
+        final String requestID = MDC.get(ONAPLogConstants.MDCs.REQUEST_ID);
+        final Map<String, String> safekeeping = MDC.getCopyOfContextMap();
+
+        // Set headers.
+
+        mock.addHeader(ONAPLogConstants.Headers.REQUEST_ID, StringUtils.defaultString(requestID));
+        mock.addHeader(ONAPLogConstants.Headers.INVOCATION_ID, invocationID.toString());
+        mock.addHeader(ONAPLogConstants.Headers.PARTNER_NAME, this.getServiceName());
+
+        try {
+
+            MDC.clear();
+
+            // Execute.
+
+            return component.execute(request, mock);
+        }
+        finally {
+
+            // Restore MDCs.
+
+            safekeeping.forEach((k, v) -> MDC.put(k, v));
+        }
+    }
+
+    /**
+     * Ensure non-nullness.
+     * @param in to be checked.
+     * @param <T> type.
+     * @return input value, not null.
+     */
+    private static <T> T notNull(final T in) {
+        if (in == null) {
+            throw new AssertionError("");
+        }
+        return in;
+    }
+
+    /**
+     * Get service name, with default.
+     * @return service name, suitable for logging as MDC.
+     */
+    private String getServiceName() {
+        return "service." + StringUtils.defaultString(this.getId(), "unnamed");
+    }
+
+    /**
+     * Get logger instance.
+     * @return logger.
+     */
+    private Logger getLogger() {
+        return LoggerFactory.getLogger(this.getClass());
+    }
+}