The Hop SDK

The Hop Java SDK Overview — Maven coordinates, environment initialization, plugin base folders, and variable management.

Pipelines API — Loading, dynamically assembling, executing pipelines, row injection, and listening to streams.

Workflows API — Loading, assembling, and executing workflows.

Metadata and Providers — Metadata architecture, providers (JsonMetadataProvider, MemoryMetadataProvider, MultiMetadataProvider, SerializableMetadataProvider), and GUI widgets (MetaSelectionLine).

File Handling with HopVFS — Unified file access via Apache Commons VFS, avoiding java.io.File, closing resources, and streaming.

Logging Subsystem — Logging registry, log channels, buffers, and capturing log output programmatically.

Plugin Development Guide — Tutorials and reference implementations for all 15 Hop plugin types.