Class FlashUpdateItemInfo

Object
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   +--FlashUpdateItemInfo

class FlashUpdateItemInfo

Contains the information related to an update of the field values for an item. It reports all the new and old values of the fields.
Defined in lsjavascriptbridge.as

Constructor Detail

FlashUpdateItemInfo

FlashUpdateItemInfo()

Used by Lightstreamer to provide a value object to each call of the FlashTable.onItemUpdate() event handler.

getNewValue

String getNewValue(<Number> fieldId)

Inquiry method that gets the new value for a specified field, as received from the Server with the current update.

Parameters:
fieldId - a Number representing a field position. In case an Array of field names was supplied to the FlashTable constructor, a String with a field name can also be specified.

Returns:
The field value; it can be null in the following cases:
• a null value has been received from the Server, as null is a possible value for a field
• the item is subscribed with the COMMAND mode and a DELETE command is received (only the fields used to carry key and command informations are valued)

getNumFields

Number getNumFields()

Inquiry method that gets the number of fields received from the Server with the current update. The value, however, is the same across all updates pertaining to the same item, because it is determined by the schema associated to the item at subscription. The fields received from the Server are always associated to consecutive field numbers starting from 1.

Returns:
The number of fields received from the Server.

getOldValue

String getOldValue(<Number> fieldId)

Inquiry method that gets the previous value for a specified field, after the reception of an update from the Server for an item. If the item is subscribed with the COMMAND mode, then the previous values refer to the last update with the same key value.

Parameters:
fieldId - a Number representing a field position. In case an Array of field names was supplied to the FlashTable constructor, a String with a field name can also be specified.

Returns:
The field previous value; it can be null in the following cases:
• a null value had been received from the Server, as null is a possible value for a field
• the item is not subscribed with the COMMAND mode and it is the first update ever received for the item (it may be a snapshot-related update)
• the item is subscribed with the COMMAND mode and it is the first update ever received for the item with the involved key field value (i.e. the event carries an "ADD" command; it may be a snapshot-related update)

isValueChanged

boolean isValueChanged(<Number> fieldId)

Inquiry method that asks whether the value for a field has changed after the reception of an update from the Server for an item. If the item is subscribed with the COMMAND mode, then the change is meant as relative to the same key.

Parameters:
fieldId - a Number representing a field position. In case an Array of field names was supplied to the FlashTable constructor, a String with a field name can also be specified.

Returns:
if the involved item is not subscribed with the COMMAND mode, then the return value is true in the following cases:
• it is the first update for the item
• the new field value is different than the previous field value received for the item
otherwise, the return value is true in the following cases:
• it is the first update for the involved key value (i.e. the event carries an "ADD" command)
• the new field value is different than the previous field value received for the item, relative to the same key value (the event must carry an "UPDATE" command)
• the event carries a "DELETE" command (this applies to all fields other than the field used to carry key information)
In all other cases, the return value is false.