GetStreams() is an overloaded method that is also used to search for and return QiStreams (also see QiStreams for information about using GetStream() to return streams). When you call an overloaded method, the software determines the most appropriate method to use by comparing the argument types specified in the call to the method definition.
The syntax is as follows:
GetStreams(string searchText, int skip, int count);
The GetStreams() overload returns QiStreams that match specific search criteria within a given tenant.
You use the searchText parameter to specify a search string. The GetStreams() method then returns any QiStreams that match the search string. The QiStreams returned are those in which the searchText is found in the stream name, the stream description, or in the tag list.
For example, assume that a tenant contains the following Streams:
| streamId | Name | Description | Tags |
| stream1 | tempA | The temperature from DeviceA | “temperature”, “DeviceA” |
| stream2 | pressureA | The pressure from DeviceA | “pressure”, “DeviceA” |
| stream3 | calcA | calculation from DeviceA values | “temperature”, “pressure”, “DeviceA” |
Using the stream data above, the following table shows the results of a GetStreams() call with different SearchText values:
| SearchText | Streams returned |
| “temp*” | stream1 and stream3 returned. |
| “calc*” | Only stream3 returned. |
| “DeviceA*” | All three streams returned. |
| “humidity*” | No streams returned. |
The skip and count parameters determine which streams are returned when a large number of streams match the searchText criteria.
The asterisk (*) character is a wildcard which matches zero or more characters (see Search operators).
count indicates the maximum number of streams returned by the GetStreams() call. The maximum value of the count parameter is 1000.
skip indicates the number of matched stream names to skip over before returning matching streams. You use the skip parameter when more streams match the search criteria than can be returned in a single call.
For example, assume there are 175 streams that match the search criteria: “temperature*”. The following call returns the first 100 matches:
GetStreams(“temperature*”, 0, 100)
After the previous call, you can use the following call to return the remaining 75 matches, skipping over the first 100 matches because of the skip parameter set at 100):
GetStreams(“temperature*”, 100, 100)
You can specify search operators in the searchText string to return more specific search results.
+ |
AND operator. For example, "cat+dog" searches for streams
containing both "cat" and "dog". |
| |
OR operator. For example, "cat|dog" searches for documents containing either "cat" or "dog" or both. |
- |
NOT operator. For example, "cat –dog" searches for streams that have the "cat" term or do not have "dog" |
* |
Suffix operator. For example, "cat*" searches for streams that have a term that starts with "cat", ignoring case. |
" |
Phrase search operator. For example, while Roach Motel (without quotes) would search for documents containing Roach Motel anywhere in any order, "Roach Motel" (with quotes) will only match documents that contain the whole phrase together and in that order. |
( ) |
Precedence operator. For example, motel+(wifi|luxury) searches for documents containing the motel term and either wifi or luxury (or both). |
QiStream objects support a collection of strings called Tags. Tags allow you to augment QiStreams with additional information, making it easier to classify, identify, and search for individual streams. The example below shows a stream being created that has the tags “Depth”, “Temperature”, and “operations” defined.