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2 * ============LICENSE_START=======================================================
4 * ================================================================================
5 * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
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7 * Licensed under the Apache License, Version 2.0 (the "License");
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21 *******************************************************************************/
22 package com.att.nsa.cambria.backends;
25 * A consumer interface. Consumers pull the next message from a given topic.
28 public interface Consumer
31 * A message interface provide the offset and message
35 public interface Message
38 * returning the offset of that particular message
43 * returning the message
50 * Get this consumer's name
56 * Get creation time in ms
59 long getCreateTimeMs ();
62 * Get last access time in ms
65 long getLastAccessMs ();
68 * Get the next message from this source. This method must not block.
69 * @return the next message, or null if none are waiting
71 Message nextMessage ();
74 * Get the next message from this source. This method must not block.
75 * @param atOffset start with the next message at or after atOffset. -1 means next from last request
76 * @return the next message, or null if none are waiting
81 * Close/clean up this consumer
86 * Commit the offset of the last consumed message
92 * Get the offset this consumer is currently at