| layout | title | categories | parent | weight |
|---|---|---|---|---|
post |
Priority Based Queue |
SBP |
processing.html |
800 |
{% tip %}
Summary: Implementing Priority based Queue
Author: Shay Hassidim, Deputy CTO, GigaSpaces
Recently tested with GigaSpaces version: XAP 8.0
Last Update: Feb 2011
Contents:
{% toc minLevel=1|maxLevel=1|type=flat|separator=pipe %}
{% endtip %}
To implement a Priority based Queue you should use the Take operation with SQLQuery having the priority field used as part of the query. This field should use the EXTENDED index type.
You can query for all objects which got their priority bigger than X (priority > X) or query for objects based on a range (Y > priority > X). In both cases the objects will be taken from the space in an orderly manner based on their field values.
See below example code:
{% highlight java %} GigaSpace space = new GigaSpaceConfigurer (new UrlSpaceConfigurer(spaceURL)).gigaSpace(); String queryStr = "priority>" + priorityMin + " and priority<"+ priorityMax; SQLQuery query = new SQLQuery(Order.class.getName(), queryStr); Object template = space.snapshot(query); while (true) { Object result = space.take (template ,100000); if result(!=null) { ... } } {% endhighlight %}
The Order Class will have the Priority indexed:
{% highlight java %} import com.gigaspaces.annotation.pojo.SpaceClass; import com.gigaspaces.annotation.pojo.SpaceId; import com.gigaspaces.annotation.pojo.SpaceIndex; import com.gigaspaces.annotation.pojo.SpaceRouting; import com.gigaspaces.metadata.index.SpaceIndexType;
@SpaceClass public class Order { public Integer priority; public Integer id; public Long timestamp; public Order() {}
public String toString()
{
return "id:" + id + " priority:" + priority + " timestamp:"+timestamp;
}
@SpaceId
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@SpaceIndex(type=SpaceIndexType.EXTENDED)
@SpaceRouting
public Integer getPriority() {
return priority;
}
public void setPriority(Integer priority) {
this.priority = priority;
}
public Long getTimestamp() {
return timestamp;
}
public void setTimestamp(Long timestamp) {
this.timestamp = timestamp;
}
} {% endhighlight %}
This is a Priority based queue example - It includes 2 parts:
-- Master - Write Orders into the space with a random priority (1-9) -- Worker - Consume Orders from the space where the consumption order is based on their priority value.
With this example we have one Master thread and two worker threads.
This demo can be modified to have:
- Different amount of queues
- Different amount of workers that deals with different queue. For example - queue with high priority Orders will have more workers than low priority Orders: Worker 1 : priorities 1-3 - High priories orders Worker 2 : priorities 4-6 - Mid priories orders Worker 3 : priorities 7-9 - Low priories orders
To run:
- Extract the attached.
- Load the example project into your IDE.
- Set the project classpath to include GigaSpaces jars located under
\gigaspaces-xap\lib\requiredfolder. - Run the
com.gigaspaces.examples.priorityq.PriorityQueueExamplemain.
Expected output:
{% highlight java %} Welcome to GigaSpaces Priority Based Queue Example .... Connect to space:/./mySpace OK! Master Started - Thread ID:99 Worker 1 Started Query:priority>0 Worker 0 Started Query:priority>0 Worker 0 priority>0 :Processing Order:id:85 priority:1 timestamp:1270582548559 Worker 1 priority>0 :Processing Order:id:82 priority:1 timestamp:1270582548499 Worker 0 priority>0 :Processing Order:id:67 priority:1 timestamp:1270582548199 Worker 1 priority>0 :Processing Order:id:56 priority:1 timestamp:1270582547978 Worker 0 priority>0 :Processing Order:id:48 priority:1 timestamp:1270582547818 Worker 1 priority>0 :Processing Order:id:44 priority:1 timestamp:1270582547738 Worker 0 priority>0 :Processing Order:id:38 priority:1 timestamp:1270582547618 Worker 1 priority>0 :Processing Order:id:35 priority:1 timestamp:1270582547558 Worker 0 priority>0 :Processing Order:id:21 priority:1 timestamp:1270582547275 Worker 1 priority>0 :Processing Order:id:15 priority:1 timestamp:1270582547155 Worker 0 priority>0 :Processing Order:id:13 priority:1 timestamp:1270582547115 Worker 1 priority>0 :Processing Order:id:8 priority:1 timestamp:1270582547015 Worker 0 priority>0 :Processing Order:id:89 priority:2 timestamp:1270582548639 Worker 1 priority>0 :Processing Order:id:87 priority:2 timestamp:1270582548599 Worker 0 priority>0 :Processing Order:id:68 priority:2 timestamp:1270582548219 Worker 1 priority>0 :Processing Order:id:53 priority:2 timestamp:1270582547918 Worker 0 priority>0 :Processing Order:id:47 priority:2 timestamp:1270582547798 Worker 1 priority>0 :Processing Order:id:36 priority:2 timestamp:1270582547578 Worker 0 priority>0 :Processing Order:id:34 priority:2 timestamp:1270582547538 Worker 0 priority>0 :Processing Order:id:84 priority:3 timestamp:1270582548539 Worker 1 priority>0 :Processing Order:id:25 priority:2 timestamp:1270582547355 Worker 0 priority>0 :Processing Order:id:80 priority:3 timestamp:1270582548459 Worker 1 priority>0 :Processing Order:id:77 priority:3 timestamp:1270582548399 Worker 0 priority>0 :Processing Order:id:58 priority:3 timestamp:1270582548019 Worker 1 priority>0 :Processing Order:id:51 priority:3 timestamp:1270582547878 Worker 0 priority>0 :Processing Order:id:46 priority:3 timestamp:1270582547778 Worker 0 priority>0 :Processing Order:id:42 priority:3 timestamp:1270582547698 Worker 0 priority>0 :Processing Order:id:37 priority:3 timestamp:1270582547598 Worker 1 priority>0 :Processing Order:id:43 priority:3 timestamp:1270582547718 Worker 1 priority>0 :Processing Order:id:7 priority:3 timestamp:1270582546995 Worker 0 priority>0 :Processing Order:id:32 priority:3 timestamp:1270582547498 Worker 1 priority>0 :Processing Order:id:2 priority:3 timestamp:1270582546889 Worker 0 priority>0 :Processing Order:id:94 priority:4 timestamp:1270582548739 Worker 1 priority>0 :Processing Order:id:90 priority:4 timestamp:1270582548659 Worker 0 priority>0 :Processing Order:id:73 priority:4 timestamp:1270582548319 Worker 1 priority>0 :Processing Order:id:62 priority:4 timestamp:1270582548099 Worker 0 priority>0 :Processing Order:id:60 priority:4 timestamp:1270582548059 Worker 1 priority>0 :Processing Order:id:55 priority:4 timestamp:1270582547958 Worker 0 priority>0 :Processing Order:id:54 priority:4 timestamp:1270582547938 Worker 1 priority>0 :Processing Order:id:30 priority:4 timestamp:1270582547455 Worker 0 priority>0 :Processing Order:id:12 priority:4 timestamp:1270582547095 Worker 1 priority>0 :Processing Order:id:9 priority:4 timestamp:1270582547035 Worker 0 priority>0 :Processing Order:id:6 priority:4 timestamp:1270582546973 Worker 1 priority>0 :Processing Order:id:81 priority:5 timestamp:1270582548479 Worker 0 priority>0 :Processing Order:id:76 priority:5 timestamp:1270582548379 Worker 1 priority>0 :Processing Order:id:72 priority:5 timestamp:1270582548299 Worker 0 priority>0 :Processing Order:id:69 priority:5 timestamp:1270582548239 Worker 1 priority>0 :Processing Order:id:66 priority:5 timestamp:1270582548179 Worker 0 priority>0 :Processing Order:id:50 priority:5 timestamp:1270582547858 Worker 1 priority>0 :Processing Order:id:45 priority:5 timestamp:1270582547758 Worker 0 priority>0 :Processing Order:id:41 priority:5 timestamp:1270582547678 Worker 0 priority>0 :Processing Order:id:18 priority:5 timestamp:1270582547215 Worker 1 priority>0 :Processing Order:id:27 priority:5 timestamp:1270582547395 Worker 0 priority>0 :Processing Order:id:17 priority:5 timestamp:1270582547195 Worker 1 priority>0 :Processing Order:id:11 priority:5 timestamp:1270582547075 Worker 0 priority>0 :Processing Order:id:93 priority:6 timestamp:1270582548719 Worker 1 priority>0 :Processing Order:id:86 priority:6 timestamp:1270582548579 Worker 0 priority>0 :Processing Order:id:83 priority:6 timestamp:1270582548519 Worker 1 priority>0 :Processing Order:id:65 priority:6 timestamp:1270582548159 Worker 0 priority>0 :Processing Order:id:63 priority:6 timestamp:1270582548119 Worker 1 priority>0 :Processing Order:id:20 priority:6 timestamp:1270582547255 Worker 0 priority>0 :Processing Order:id:3 priority:6 timestamp:1270582546909 Worker 1 priority>0 :Processing Order:id:1 priority:6 timestamp:1270582546794 Worker 0 priority>0 :Processing Order:id:91 priority:7 timestamp:1270582548679 Worker 1 priority>0 :Processing Order:id:74 priority:7 timestamp:1270582548339 Worker 0 priority>0 :Processing Order:id:71 priority:7 timestamp:1270582548279 Worker 1 priority>0 :Processing Order:id:59 priority:7 timestamp:1270582548039 Worker 0 priority>0 :Processing Order:id:57 priority:7 timestamp:1270582547999 Worker 0 priority>0 :Processing Order:id:49 priority:7 timestamp:1270582547838 Worker 1 priority>0 :Processing Order:id:52 priority:7 timestamp:1270582547898 Worker 0 priority>0 :Processing Order:id:39 priority:7 timestamp:1270582547638 Worker 1 priority>0 :Processing Order:id:31 priority:7 timestamp:1270582547475 Worker 0 priority>0 :Processing Order:id:26 priority:7 timestamp:1270582547375 Worker 1 priority>0 :Processing Order:id:22 priority:7 timestamp:1270582547295 Worker 0 priority>0 :Processing Order:id:16 priority:7 timestamp:1270582547175 Worker 1 priority>0 :Processing Order:id:14 priority:7 timestamp:1270582547135 Worker 0 priority>0 :Processing Order:id:5 priority:7 timestamp:1270582546949 Worker 1 priority>0 :Processing Order:id:4 priority:7 timestamp:1270582546929 Worker 0 priority>0 :Processing Order:id:96 priority:8 timestamp:1270582548779 Worker 1 priority>0 :Processing Order:id:78 priority:8 timestamp:1270582548419 Worker 0 priority>0 :Processing Order:id:75 priority:8 timestamp:1270582548359 Worker 1 priority>0 :Processing Order:id:64 priority:8 timestamp:1270582548139 Worker 0 priority>0 :Processing Order:id:28 priority:8 timestamp:1270582547415 Worker 1 priority>0 :Processing Order:id:24 priority:8 timestamp:1270582547335 Worker 0 priority>0 :Processing Order:id:23 priority:8 timestamp:1270582547315 Worker 1 priority>0 :Processing Order:id:19 priority:8 timestamp:1270582547235 Worker 0 priority>0 :Processing Order:id:95 priority:9 timestamp:1270582548759 Worker 1 priority>0 :Processing Order:id:92 priority:9 timestamp:1270582548699 Worker 0 priority>0 :Processing Order:id:88 priority:9 timestamp:1270582548619 Worker 1 priority>0 :Processing Order:id:79 priority:9 timestamp:1270582548439 Worker 0 priority>0 :Processing Order:id:70 priority:9 timestamp:1270582548259 Worker 1 priority>0 :Processing Order:id:61 priority:9 timestamp:1270582548079 Worker 0 priority>0 :Processing Order:id:40 priority:9 timestamp:1270582547658 Worker 1 priority>0 :Processing Order:id:33 priority:9 timestamp:1270582547518 Worker 0 priority>0 :Processing Order:id:29 priority:9 timestamp:1270582547435 Worker 1 priority>0 :Processing Order:id:10 priority:9 timestamp:1270582547055 {% endhighlight %}