ddsf:public:guidebook:06_append:glossary:d:data_writer
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
ddsf:public:guidebook:06_append:glossary:d:data_writer [2019/05/12 21:15] admin ↷ Page moved from ddsf:public:resources:glossary:d:data_writer to ddsf:public:resources:appendix:glossary:d:data_writer |
ddsf:public:guidebook:06_append:glossary:d:data_writer [2021/07/14 16:37] (current) murphy ↷ Links adapted because of a move operation |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| ==== Data Writer ==== | ==== Data Writer ==== | ||
| - | DataWriter objects are responsible for sending type-specific data to one or more DataReaders. | + | [[ddsf:public:guidebook:06_append:glossary:start| Return to Glossary ]] |
| - | A DataWriter is created with a Topic, which gives a name to the data stream and associates the DataWriter with a data type. A DataWriter sends data to one or more DataReaders if the DataWriter and DataReader(s): | + | An [[ddsf:public:guidebook:06_append:glossary:e:entity|entity]] attached to a [[ddsf:public:guidebook:06_append:glossary:p:publisher|Publisher]] bound to publish samples from only |
| + | one [[ddsf:public:guidebook:06_append:glossary:t:topic|Topic]] and therefore exactly one data type, providing type-safe | ||
| + | operations to write/send data. The Topic must be created before the | ||
| + | Data Writer. | ||
| - | * have Topics with the same name | + | Source: [[https://istkb.adlinktech.com/article/vortex-opensplice-dds-glossary/ | OpenSplice Glossary]] |
| - | * have data types that are assignable to each other (not necessarily identical) | + | |
| - | * are within the same domain | + | |
| - | * have compatible QoS | + | |
| - | * can be discovered and communicate with each other over one or more transports | + | |
| - | The behavior of a DataWriter is controlled by QoS. For example, a DataWriter can be made reliable by configuring its RELIABILITY QoS. A DataWriter provides asynchronous notifications in the form of Status Changes. | ||
| - | |||
| - | There are two types of objects that can be referred to as DataWriters: DDS DataWriter objects and type-specific DataWriter objects (usually called FooDataWriter to indicate a user data type “Foo”). | ||
| - | |||
| - | The DDS::DataWriter object is used for actions that are not specific to a single data type, such as configuring QoS or installing listeners. The type-specific FooDataWriter object is used for actions that involve the specific data type, such as writing data or unregistering/disposing of an instance. | ||
| - | |||
| - | For example, when writing data, you must use a type-specific DataWriter, rather than the generic DataWriter class: | ||
| - | |||
| - | <Code C linenums:1 | Example of using a DDS DataWriter> | ||
| - | // Create the DDS::DataWriter. This object can be used for configuring QoS, | ||
| - | // asserting liveliness, or other non-type specific actions. | ||
| - | DDS::DataWriter *ddsWriter | ||
| - | = publisher->create_datawriter | ||
| - | ( medicalDataTopic, | ||
| - | qos, | ||
| - | listener, | ||
| - | DDS_STATUS_MASK_ALL | ||
| - | ); | ||
| - | // Create the type-specific DataWriter. This object can be used for writing data, | ||
| - | // disposing a data-instance, or other actions that are specific to a data type | ||
| - | MedicalDeviceDataWriter *medicalDataWriter | ||
| - | = MedicalDeviceDataWriter::narrow(ddsWriter); | ||
| - | medicalDataWriter->write(deviceData, ...); | ||
| - | </Code> | ||
ddsf/public/guidebook/06_append/glossary/d/data_writer.1557710157.txt.gz · Last modified: 2019/05/12 21:15 by admin
