org.eclipse.scada.da.server.common.chain

Interface ChainItem

All Known Implementing Classes:

AutoTimestampChainItem, BaseChainItemCommon, SumAlarmChainItem, SumErrorChainItem, SummarizeChainItem, SumPatternAttributesChainItem

public interface ChainItem

A chain element

An instance of chain element may only be added to one data item

Author:

Jens Reimann

Method Summary

Modifier and Type	Method and Description
Variant	process(Variant value, Map<String,Variant> attributes) Process the chain item
WriteAttributeResults	setAttributes(Map<String,Variant> attributes) Request to set attributes

Method Detail

setAttributes

WriteAttributeResults setAttributes(Map<String,Variant> attributes)

Request to set attributes

Parameters:

attributes - the attributes update set

Returns:

result for processed attributes

process

Variant process(Variant value,
                Map<String,Variant> attributes)

Process the chain item

Parameters:

value - the value to process or null if a output item changed only the attributes

attributes - The current primary attributes

Returns:

the new result or null if the chain item does not change the input value