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2 * ============LICENSE_START=======================================================
4 * ================================================================================
5 * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
6 * ================================================================================
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
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15 * See the License for the specific language governing permissions and
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17 * ============LICENSE_END=========================================================
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21 *******************************************************************************/
22 package com.att.dmf.mr.backends;
24 import java.util.ArrayList;
27 * A consumer interface. Consumers pull the next message from a given topic.
30 public interface Consumer
33 * A message interface provide the offset and message
34 * @author nilanjana.maity
37 public interface Message
40 * returning the offset of that particular message
45 * returning the message
52 * Get this consumer's name
58 * Get creation time in ms
61 long getCreateTimeMs ();
64 * Get last access time in ms
67 long getLastAccessMs ();
70 * Get the next message from this source. This method must not block.
71 * @return the next message, or null if none are waiting
73 Message nextMessage ();
76 * Get the next message from this source. This method must not block.
77 * @param atOffset start with the next message at or after atOffset. -1 means next from last request
78 * @return the next message, or null if none are waiting
84 * Close/clean up this consumer
90 * Commit the offset of the last consumed message
96 * Get the offset this consumer is currently at
101 void setOffset(long offset);