1 files changed, 148 insertions, 0 deletions
diff --git a/dcae-analytics/dcae-analytics-web/src/main/java/org/onap/dcae/analytics/web/dmaap/MrSubscriberPollingAdvice.java b/dcae-analytics/dcae-analytics-web/src/main/java/org/onap/dcae/analytics/web/dmaap/MrSubscriberPollingAdvice.java
new file mode 100644
index 0000000..33115c5
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+++ b/dcae-analytics/dcae-analytics-web/src/main/java/org/onap/dcae/analytics/web/dmaap/MrSubscriberPollingAdvice.java
@@ -0,0 +1,148 @@
+/*
+ * ================================================================================
+ * Copyright (c) 2018 AT&T Intellectual Property. 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.dcae.analytics.web.dmaap;
+
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.onap.dcae.analytics.model.AnalyticsHttpConstants;
+import org.onap.dcae.analytics.model.DmaapMrConstants;
+import org.onap.dcae.analytics.web.util.AnalyticsHttpUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.integration.handler.advice.AbstractRequestHandlerAdvice;
+import org.springframework.integration.support.MessageBuilder;
+import org.springframework.integration.util.DynamicPeriodicTrigger;
+import org.springframework.messaging.Message;
+
+/**
+ * A polling advice which can auto adjust polling intervals depending on DMaaP MR message availability.
+ * Can be configured to slow down polling when messages are not available and increase polling when messages are
+ * indeed available.
+ * <p>
+ * The next polling interval is <b>increased</b> by given step up delta if message is <b>not found</b> up to maximum
+ * Polling Interval
+ * <br>
+ * The next polling interval is <b>decreased</b> by step down delta if message <b>is found</b> up to minimum
+ * polling interval
+ *
+ * @author Rajiv Singla
+ */
+public class MrSubscriberPollingAdvice extends AbstractRequestHandlerAdvice {
+
+    private static final Logger log = LoggerFactory.getLogger(MrSubscriberPollingAdvice.class);
+
+    private final DynamicPeriodicTrigger trigger;
+    private final int minPollingInterval;
+    private final int stepUpPollingDelta;
+    private final int maxPollingInterval;
+    private final int stepDownPollingDelta;
+
+    private final AtomicInteger nextPollingInterval;
+
+    /**
+     * Creates variable polling intervals based on message availability.
+     *
+     * @param trigger Dynamic Trigger instance
+     * @param minPollingInterval Minimum polling interval
+     * @param stepUpPollingDelta Delta by which next polling interval will be increased when message is not found
+     * @param maxPollingInterval Maximum polling interval
+     * @param stepDownPollingDelta Delta by which next polling interval will be decreased when message is found
+     */
+    public MrSubscriberPollingAdvice(final DynamicPeriodicTrigger trigger,
+                                     final int minPollingInterval,
+                                     final int stepUpPollingDelta,
+                                     final int maxPollingInterval,
+                                     final int stepDownPollingDelta) {
+        this.trigger = trigger;
+        this.minPollingInterval = minPollingInterval;
+        this.stepUpPollingDelta = stepUpPollingDelta;
+        this.maxPollingInterval = maxPollingInterval;
+        this.stepDownPollingDelta = stepDownPollingDelta;
+        nextPollingInterval = new AtomicInteger(minPollingInterval);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    protected Object doInvoke(final ExecutionCallback callback, final Object target, final Message<?> message)
+            throws Exception {
+
+        // execute call back
+        Object result = callback.execute();
+
+        // if result is not of type message builder just return
+        if (!(result instanceof MessageBuilder)) {
+            return result;
+        }
+
+        final MessageBuilder<String> resultMessageBuilder = (MessageBuilder<String>) result;
+        final String payload = resultMessageBuilder.getPayload();
+        final Map<String, Object> headers = resultMessageBuilder.getHeaders();
+        final Object httpStatusCode = headers.get(AnalyticsHttpConstants.HTTP_STATUS_CODE_HEADER_KEY);
+
+        // get http status code
+        if (httpStatusCode == null) {
+            return result;
+        }
+        final HttpStatus httpStatus = HttpStatus.resolve(Integer.parseInt(httpStatusCode.toString()));
+
+
+        // if status code is present and successful apply polling adjustments
+        if (httpStatus != null && httpStatus.is2xxSuccessful()) {
+            final boolean areMessagesPresent = areMessagesPresent(payload);
+            updateNextPollingInterval(areMessagesPresent);
+
+            final String requestId = AnalyticsHttpUtils.getRequestId(message.getHeaders());
+            final String transactionId = AnalyticsHttpUtils.getTransactionId(message.getHeaders());
+
+            log.debug("Request Id: {}, Transaction Id: {}, Messages Present: {}, " +
+                            "Next Polling Interval will be: {}", requestId, transactionId,
+                    areMessagesPresent, nextPollingInterval);
+
+            trigger.setPeriod(nextPollingInterval.get());
+
+            // if no messages were found in dmaap poll - terminate further processing
+            if (!areMessagesPresent) {
+                log.info("Request Id: {}, Transaction Id: {}, No new messages found in DMaaP MR Response. " +
+                        "No further processing required", requestId, transactionId);
+                return null;
+            }
+
+        }
+
+        return result;
+    }
+
+    private boolean areMessagesPresent(final String payload) {
+
+        return !(payload.isEmpty() || payload.equals(DmaapMrConstants.SUBSCRIBER_EMPTY_MESSAGE_RESPONSE_STRING));
+    }
+
+    private void updateNextPollingInterval(final boolean areMessagesPresent) {
+        if (areMessagesPresent) {
+            nextPollingInterval.getAndUpdate(interval -> interval - stepDownPollingDelta <= minPollingInterval ?
+                    minPollingInterval : interval - stepDownPollingDelta);
+        } else {
+            nextPollingInterval.getAndUpdate(interval -> interval + stepUpPollingDelta >= maxPollingInterval ?
+                    maxPollingInterval : interval + stepUpPollingDelta);
+        }
+    }
+}