Class MultiDynaMetapushTable

Object
   |
   +--Table
         |
         +--VisualTable
               |
               +--DynaMetapushTable
                     |
                     +--MultiDynaMetapushTable

class MultiDynaMetapushTable

extends DynaMetapushTable

A data table that can be fed with real-time data delivered by Lightstreamer Server and displayed into a screen table according to ADD, UPDATE and DELETE commands received as pushed values, which instruct the data table to either add a row, just modify values on a row or delete a row. However, the values for each data table row are provided:

• in part through the ADD and UPDATE commands;
• in part through a second-level, or "underlying" item, determined by the row key, which defines an implicit row-like data table, automatically created and managed according to the row lifecycle.

- FieldDescriptor

Constructor Detail

MultiDynaMetapushTable

MultiDynaMetapushTable(<GroupDescriptor> tGroup, <SchemaDescriptor> tSchema, <String> tSubscriptionMode, <SchemaDescriptor> tUnderSchema)

Creates an object to be used to describe a data table to be managed with a "MultiMetapush logic" behaviour. The table rows are displayed into dynamically generated HTML rows. The object can be supplied to PushPage.addTable() and PushPage.removeTable(), in order to bring the data table to "running" or back to "inactive" state.

Parameters:
tGroup - A group descriptor object, which identifies the first-level items that provide the data table rows. Usually, the group consists of just one item, whose updates are commands that specify whether to ADD, UPDATE or DELETE data table rows. If the group consists of more than one item, then the updates for the different items are simply mixed and concur to the maintenance of the same data table. However, if the same key is used by different items, it refers to distinct rows on the data table, which will be related to identical underlying tables.
An Array of item names or a String group identifier can also be used directly, instead of a group descriptor object.
Note that, in case a GroupListDescriptor or an array is used, a LiteralBasedProvider or equivalent Metadata Adapter is needed on the Server in order to understand the subscription request.
tSchema - A schema descriptor object, which identifies the fields provided by the first-level items. An Array of field names or a String schema identifier can also be used directly, instead of a schema descriptor object.
In case a SchemaListDescriptor or a field name array is specified, field names can be used in the cells as field descriptors; otherwise, only field positions can be used.
A null value is also allowed. In this case, the names for the fields should be supplied by the associated screen tables; hence, field names should be used in the cells as field descriptors. Names starting with a "#" character will be treated as extra fields and not included in the schema (hence, if extra fields have to be put in the cells, in order to use this feature, names starting with "#" should be chosen for the extra fields). Names preceded by the "$" character, on the other hand, identify fields provided by the second-level items and are not included in the first-level schema. If COMMAND subscription mode is specified, then the special "key" and "command" fields are automatically added.
Note that, in case a SchemaListDescriptor, an array or a null value is supplied, a LiteralBasedProvider or equivalent Metadata Adapter is needed on the Server in order to understand the subscription request.
tSubscriptionMode - the subscription mode for the first-level items of the main table, required by Lightstreamer Server. This kind of data table is suited for COMMAND mode.
tUnderSchema - a schema descriptor object, which identifies the fields provided by the second-level items (i.e. the fields that represent the underlying data table columns). An Array of field names or a String schema identifier can also be used directly, instead of a schema descriptor object.
In case a SchemaListDescriptor or a field name array is specified, field names can be used in the cells as field descriptors, provided that the names are preceded by the "$" character; a real field name can also be used whenever there is no conflict with first-level fields. Otherwise, only field positions can be used; in this case, the field position indexes to be used should start from the highest position of the first-level schema + 1.
Similar considerations hold for the DynaMetapushTable.setMetapushSort(), DynaMetapushTable.getMetapushSortField() and DynaMetapushTable.getMetapushSortFieldName() methods, when second-level fields are used for sorting; in particular, the latter method returns the real field name whenever there is no conflict with first-level fields and returns the name preceded by the "$" character otherwise.
A null value is also allowed. In this case, the names for the fields should be supplied by the associated screen tables; hence, the field names should be used in the cells as field descriptors, again provided that the names are preceded by the "$" character.
Note that, in case a SchemaListDescriptor, an array or a null value is supplied, a LiteralBasedProvider or equivalent Metadata Adapter is needed on the Server in order to understand the subscription request.
Note that the first-level and second-level schemas must be declared in the same way, i.e. both through a SchemaListDescriptor (or an array, or null) or both through a SchemaIdDescriptor (or an identifier).

See:
- FieldDescriptor

setUnderDataAdapter

void setUnderDataAdapter(<String> dataAdapter)

Setter method that sets the name of the underlying Data Adapter (within the Adapter Set used by the current session) that supplies all the second-level items. All the possible second-level items should be supplied in "MERGE" mode with snapshot available.
The Data Adapter name is configured on the server side through the "name" attribute of the "data_provider" element, in the "adapters.xml" file that defines the Adapter Set (a missing attribute configures the "DEFAULT" name).

Invocation: optional.

Default value: "DEFAULT".

Lifecycle: The underlying Data Adapter name should be set and changed while the main data table is in "inactive" state. Each time a new underlying data table is created and brought to "running" state due to an ADD operation on the main data table, the underlying Data Adapter name is specified in the subscription request.

Parameters:
dataAdapter - the name of the Data Adapter. A null value is equivalent to the "DEFAULT" name.

See:
- Connection.setAdapterName()