filter/query

[DarioCrivelli]

Hi James

There is no built-in query management in Lightstreamer. However, the client can ask your adapters to perform filtering queries on the data in a couple of ways.

1) By embedding the query in the item name, as (for instance) in

var schema = " command key id";
var table = new DynaMetapushTable("XYZ[accountId=12345]", schema, "COMMAND");

The Data Adapter is then responsible for recognizing each query as a legal item name, parsing it and supply data accordingly.

2) By defining a Selector for a generic item and embedding the query in the Selector name, as in

var schema = " command key id";
var table = new DynaMetapushTable("XYZ", schema, "COMMAND");
table.setSelector("accountId=12345");

The Metadata Adapter is then responsible for parsing and accepting the Selector name and recognizing the embedded query in isSelectorAllowed; then, for each event of the generic item, it should filter it according to the filter query in isSelected.
See also this topic.

Note that architectural and performance issues may guide the choice.

Dario