Pipeline

All processing within Cocoon is handled within a pipeline. i.e. input, zero or more processing stages, and ultimately some output.

Processing steps are modelled as different types of Components, the simplest pipeline is:

• Input: Generator

• Processing: Transformer

• Output: Serializer

Therefore a pipeline consists of a generator, zero or more transformers and a serializer. A pipeline may also define its own ErrorHandling.

Requests to Cocoon are mapped to pipeline by a Matcher or a Selector. These are configured in the Sitemap.

Aggregator allow pipeline to be configured into a hierarchy, producing a compound document.

Definition

The map:pipeline element can contain:

• map:match -- Selects pipeline processing depending on Matcher
• map:select, map:when, map:otherwise -- Selector pipeline processing depending on Selector

• map:mount -- Mounts a sub Sitemap

• map:redirect-to -- Redirects to another pipeline

• map:parameter -- Defines additional parameters for the sitemap components
• map:act -- Peform Action processing
• map:generate -- Defines the Generator step
• map:aggregate, map:part -- Defines an alternate generation step by merging pipelines
• map:transform -- Defines zero or more Transformer steps
• map:serialize -- Defines the final Serializer step

• map:handle-errors -- ErrorHandling

Types of Pipeline

• Normal pipelines

• Internal pipelines -- can't be accessed externally, can only be addressed from within a sitemap. Specified by internal-only="true" attribute on map:pipeline

• Resource pipelines -- basically normal pipelines that act as reusable definitions that can be called by others. See Resources

• Error pipelines -- defined within handle-errors section. Fixed error Generator which is provided automatically by Cocoon, subsequent processing under user definition. See ErrorHandling