Activity - blockAggregator

Activity Type: Transformation

Description

Aggregate the blocks of data output from other activities into a single, larger block. This can be used to reduce network traffic when transferring data, for example.

Example

<blockAggregator name="aggregator">
  <input from="blocksToAggregate"/>
  <blocksize size="10"/>
  <output name="aggregatedBlocks"/>
</blockAggregator>

Specification

Element blockAggregator:

• Attribute name - unique name for the activity within the scope of a request.
• Element input (required) - the string data blocks to aggregate.
  • Attribute from - input stream providing the blocks.
• blocksize (required) - aggregation size.
  • Attribute size - number of blocks to be aggregated.
• output (required) - output stream for the aggregated block.
  • Attribute name - name of this output stream.

Input and Output Types

• Input: input - java.lang.String
• Output: output - java.lang.String

Limitations

Currently only string blocks can be aggregated.

Data Resource Accessor

This activity can operate with any data resource accessor.

XML Schema

OGSA-DAI/schema/ogsadai/xsd/activities/block_aggregator.xsd

Class

uk.org.ogsadai.activity.transform.BlockAggregatorActivity

Client Toolkit Class

uk.org.ogsadai.client.toolkit.activity.transform.BlockAggregator