ddsf:public:guidebook:06_append:glossary:i:instance
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ddsf:public:guidebook:06_append:glossary:i:instance [2021/07/14 15:46] murphy ↷ Page moved from ddsf:private:guidebook:06_append:glossary:i:instance to ddsf:public:guidebook:06_append:glossary:i:instance |
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| ==== Instance ==== | ==== Instance ==== | ||
| - | An instance is a unique element within a [[ddsf:private:guidebook:06_append:glossary:t:topic|Topic]], described by unique values of [[ddsf:private:guidebook:06_append:glossary:k:key|key fields]]. | + | An instance is a unique element within a [[ddsf:public:guidebook:06_append:glossary:t:topic|Topic]], described by unique values of [[ddsf:public:guidebook:06_append:glossary:k:key|key fields]]. |
| Instances represent individual real-world objects within a single data stream. For example, you can represent individual radar tracks within a single "TrackData" topic, or individual components of a wind turbine within a "TurbineComponentState" topic. What constitutes an instance will be different depending on what you are representing in your Topic. | Instances represent individual real-world objects within a single data stream. For example, you can represent individual radar tracks within a single "TrackData" topic, or individual components of a wind turbine within a "TurbineComponentState" topic. What constitutes an instance will be different depending on what you are representing in your Topic. | ||
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| Modeling your data with unique instances gives you several advantages, including: | Modeling your data with unique instances gives you several advantages, including: | ||
| - | * [[ddsf:private:guidebook:06_append:glossary:s:scalable|Scalability]] when representing many thousands of objects - you can use a single DataReader to receive the state of all the instances within a topic | + | * [[ddsf:public:guidebook:06_append:glossary:s:scalable|Scalability]] when representing many thousands of objects - you can use a single DataReader to receive the state of all the instances within a topic |
| * Quality of Service applied per-instance: Some quality of service behaviors are applied per-instance. For example, the [[ddsf:public:guidebook:06_append:glossary:h:history_qos|HISTORY QoS]] is applied per-instance, which allows you to store a certain number of updates for every instance. Note that you cannot specify different QoS for specific instances within the same DataWriter or DataReader. The QoS is set on the writer or reader, and applied on each instance. A description of all QoS, including information on which QoS policies are applied per-instance is here. | * Quality of Service applied per-instance: Some quality of service behaviors are applied per-instance. For example, the [[ddsf:public:guidebook:06_append:glossary:h:history_qos|HISTORY QoS]] is applied per-instance, which allows you to store a certain number of updates for every instance. Note that you cannot specify different QoS for specific instances within the same DataWriter or DataReader. The QoS is set on the writer or reader, and applied on each instance. A description of all QoS, including information on which QoS policies are applied per-instance is here. | ||
| * Life-cycle information is available for instances: A receiving application can detect whether an instance is alive or not. A sending application can change the instance state. | * Life-cycle information is available for instances: A receiving application can detect whether an instance is alive or not. A sending application can change the instance state. | ||
ddsf/public/guidebook/06_append/glossary/i/instance.1626291981.txt.gz · Last modified: 2021/07/14 15:46 by murphy
