A helpKey properties file defines the mapping of helpKey constants (property keys), either to actual help context IDs, or to context-specific help search expressions.
helpKey properties files are usually contributed in pairs, one for context IDs and one for search expressions.
The help context ID strings defined in a helpKey properties file cannot be fully-qualified context IDs. They must not include any blank space or period (.) characters. The DTP help-helper handles unqualified help context IDs defined in properties files to fully-qualify them, before it returns them to the UI control through the ContextProviderDelegate.
The following excerpt is from a helpKey properties file, which is contributed by the org.eclipse.datatools.doc.user.contexts plug-in to define concrete help context ID strings.
...
# CONTEXT_ID_CP_PROPERTY_PAGE =
# Basic profile name/description/auto-connect property page
CONTEXT_ID_CP_PROPERTY_PAGE = CONNECTION_PROFILE_COMMON_PROPERTY_PAGE
# CONTEXT_ID_CP_WIZARD_PAGE =
# wizard selection page in New Connection Profile wizard
CONTEXT_ID_CP_WIZARD_PAGE = NEW_CONNECTION_PROFILE_WIZARD
# CONTEXT_ID_INTRO_WIZARD_PAGE =
# Basic intro page for new connection profile wizard
CONTEXT_ID_INTRO_WIZARD_PAGE = NEW_CONNECTION_PROFILE_WIZARD
...
Notice that two abstract help contexts (represented by the helpKey constants CONTEXT_ID_CP_WIZARD_PAGE and CONTEXT_ID_INTRO_WIZARD_PAGE) are mapped to one concrete help context ID (NEW_CONNECTION_PROFILE_WIZARD). This is an example of the flexibility afforded by abstract help contexts, allowing the UA component to combine multiple abstract help contexts in a single, concrete help context ID, which is independent of the help context implementation in the UI component.
The following example shows the mapping of a helpKey constant to a context-specific help search expression in a helpKey properties file.
...
# * CONTEXT_ID_CP_PROPERTY_PAGE =
# * Basic profile name/description/auto-connect property page
CONTEXT_ID_CP_PROPERTY_PAGE = "connection profile" AND "properties"
...
Search expression strings must conform to the rules for Apache Lucene query parser syntax: http://lucene.apache.org/java/docs/queryparsersyntax.html