Package com.exalead.search.query.prefix

A Visitor class that provides callbacks on Prefix nodes to do custom processing on query branches, such as "lang:(fr OR de)".
This package includes a small extensible framework to handle custom prefix, as well as some implementations for default prefixes such as full-text, category or date.

See: Description

Interface Summary

Interface	Description
PrefixHandler	Handle a given prefix within the scope of a NodeVisitor.

Class Summary

Class	Description
AlphanumPrefix	Sets multiple index fields on all alphanum below the prefix. This handler can perform either a OR or MAX expansion. This handler removes the PrefixNode. This handler also handles the autoWildcard option during the post parse phase
BaseNumericalPrefix	This handler replaces an untransformed PrefixNode containing numerical content by a numerical node targeting a given index field.
CategoryPrefix	Prefix that performs a category match relative to a root path in a category field.
CustomPrefixHandler	Custom prefix handler
DatePrefix	This handler replaces an untransformed PrefixNode containing date leaves by a branch with date nodes targeting a given index field. The date nodes are Numerical nodes under the format used by the index.
DynamicDateFieldPrefix
DynamicNumericalFieldPrefix
EnumFacetPrefixHandler	This handler replaces an untransformed PrefixNode containing an EnumFacet content by a numerical node built from the referenced EnumFacet definition.
ErrorPrefix	A prefix that triggers an error
GeoPrefix
KeywordPrefix
NoOpPrefix	A prefix that removes itself at PRE_TRANSFORM stage
NoSpellCheck	A prefix that removes itself at PRE_TRANSFORM stage and disables spellcheck
NumericalPrefix	This handler replaces an untransformed PrefixNode containing numerical content by a numerical node targeting a given index field.
PositionPrefix	Prefix handler for prefixes "exact", "starts with", "ends with" (all position relative).
PrefixHandler.NoHooks
PrefixHandlerContext	Gives all relevant config and context elements to the Prefix handler
PrefixSupervisor	This visitor applies multiple PrefixHandler to a query node. Depending on the currently selected "phase" of the visitor, one of the several call-backs of the PrefixHandler will be called.
RefinePrefix	Prefix that performs a category match.
SimilarDocumentPrefix	This handler accepts queries of the form similar:(keyword_id keyword_id ...) where keyword ids are strings from V62015x.
SitePrefix
SplitPrefix
TemplatePrefix	Replaces the prefix by a new AST of its content
TemplatePrefixSupervisor
UnitsOfMeasurementPrefix	This handler accepts queries of the form measure>3cm His role is to detect cm as centi meters unit of measurement via a MOT pipeline, convert the value in the index unit and delegate the "superior to value" operation to a numerical prefix.
UnixTimestampPrefix	This handler replaces an untransformed PrefixNode containing unix timestamp leaves by a branch with date nodes targeting a given index field. The date nodes are Numerical nodes under the format used by the index.

Enum Summary

Enum	Description
PrefixHandler.ErrorBehaviour	What to do when the prefix handler cannot work
PrefixHandler.Phase	Processing phase for the prefix
PrefixSupervisor.MissingPrefixBehaviour

Package com.exalead.search.query.prefix Description

A Visitor class that provides callbacks on Prefix nodes to do custom processing on query branches, such as "lang:(fr OR de)".
This package includes a small extensible framework to handle custom prefix, as well as some implementations for default prefixes such as full-text, category or date.

PrefixSupervisor visitor

This is the visitor to add in the QueryProcessor to support prefixes.
It calls back the registered PrefixHandlers when stumbling upon Prefix nodes. It supports nesting, calling sequentially a full-text prefix handler then a approximate prefix handler when visiting a tree like "text:("vorpal sword" AND spellslike:jaberwok)"

Current implementation defines three sets of callbacks:

• a callback on the abstract syntax tree before tokenization and linguistic expansion
• a callback on the abstract syntax tree right after linguistic expansion
• a callback on the final abstract syntax tree

PrefixHandlers

Interface. PrefixHandler is the interface defining the three callbacks used by the PrefixSupervisor visitor.

• preHandle is the callback on the non-tokenized branch.
• handlePrefix is the callback on the tokenized and expanded branch.
• postHandle is the callback on the final branch.

Implementations. Class AlphanumPrefix provides the callbacks needed to target a set of index field. E.g. prefix "text" could target fields "title" and "body", and a query "text:(looking glass)" would result in a final tree (title=looking AND title=glass) OR (body=looking AND body=glass)
Classes NumericalPrefix and DatePrefix provide callbacks needed to target index fields of type numerical, date and time. These prefixes do not support nesting.