com.yahoo.search.federation

Class FederationSearcher

java.lang.Object

com.yahoo.component.AbstractComponent

com.yahoo.component.chain.ChainedComponent

com.yahoo.processing.Processor

com.yahoo.search.Searcher

com.yahoo.search.searchchain.ForkingSearcher

com.yahoo.search.federation.FederationSearcher

All Implemented Interfaces:

com.yahoo.component.Component, Comparable<com.yahoo.component.Component>

public class FederationSearcher
extends ForkingSearcher

This searcher takes a set of sources, looks them up in config and fire off the correct searchchains.

Author:

Arne Bergene Fossaa, Tony Vaagenes, bratseth

Nested Class Summary

Nested classes/interfaces inherited from class com.yahoo.search.searchchain.ForkingSearcher

ForkingSearcher.CommentedSearchChain

Field Summary

Fields

Modifier and Type	Field and Description
static String	FEDERATION
static String	LOG_COUNT_PREFIX Logging field name constants
static com.yahoo.processing.request.CompoundName	PROVIDERNAME
static com.yahoo.processing.request.CompoundName	SOURCENAME The name of the query property containing the source name added to the query to each source by this

Fields inherited from class com.yahoo.component.AbstractComponent

isDeconstructable

Constructor Summary

Constructors

Constructor and Description
FederationSearcher(com.yahoo.component.ComponentId id, SearchChainResolver searchChainResolver)
FederationSearcher(FederationConfig config, StrictContractsConfig strict, com.yahoo.component.provider.ComponentRegistry<TargetSelector> targetSelectors)

Method Summary

Modifier and Type	Method and Description
com.yahoo.errorhandling.Results<SearchChainInvocationSpec,UnresolvedSearchChainException>	defaultSearchChains(Properties sourceToProviderMap)
void	fill(Result result, String summaryClass, Execution execution) Fill hit properties with data using the given summary class.
Collection<ForkingSearcher.CommentedSearchChain>	getSearchChainsForwarded(SearchChainRegistry registry) Returns which searchers this searcher may forward to, for debugging and tracing
static Properties	getSourceProperties(Query query) Returns the set of properties set for the source or provider given in the query (if any).
Result	search(Query query, Execution execution) Override this to implement your searcher.

Methods inherited from class com.yahoo.search.Searcher

ensureFilled, getLogger, process, toString

Methods inherited from class com.yahoo.component.chain.ChainedComponent

getAnnotatedDependencies, getDefaultAnnotatedDependencies, getDependencies, initDependencies

Methods inherited from class com.yahoo.component.AbstractComponent

clone, compareTo, deconstruct, getClassName, getId, getIdString, hasInitializedId, initId, isDeconstructable, setIsDeconstructable

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

FEDERATION

public static final String FEDERATION

See Also:

Constant Field Values

SOURCENAME

public static final com.yahoo.processing.request.CompoundName SOURCENAME

The name of the query property containing the source name added to the query to each source by this

PROVIDERNAME

public static final com.yahoo.processing.request.CompoundName PROVIDERNAME

LOG_COUNT_PREFIX

public static final String LOG_COUNT_PREFIX

Logging field name constants

See Also:

Constant Field Values

Constructor Detail

FederationSearcher

@Inject
public FederationSearcher(FederationConfig config,
                                  StrictContractsConfig strict,
                                  com.yahoo.component.provider.ComponentRegistry<TargetSelector> targetSelectors)

FederationSearcher

public FederationSearcher(com.yahoo.component.ComponentId id,
                          SearchChainResolver searchChainResolver)

Method Detail

search

public Result search(Query query,
                     Execution execution)

Description copied from class: Searcher

Override this to implement your searcher.

Searcher implementation subclasses will, depending on their type of logic, do one of the following:

• Query processors: Access the query, then call execution.search and return the result
• Result processors: Call execution.search to get the result, access it and return
• Sources (which produces results): Create a result, add the desired hits and return it.
• Federators (which forwards the search to multiple subchains): Call search on the desired subchains in parallel and get the results. Combine the results to one and return it.
• Workflows: Call execution.search as many times as desired, using different queries. Eventually return a result.

Hits come in two kinds - concrete hits are actual content of the kind requested by the user, meta hits are hits which provides information about the collection of hits, on the query, the service and so on.

The query specifies a window into a larger result list that must be returned from the searcher through hits and offset; Searchers which returns list of hits in the top level in the result must return at least hits number of hits (or if impossible; all that are available), starting at the given offset. In addition, searchers are allowed to return any number of meta hits (although this number is expected to be low). For hits contained in nested hit groups, the concept of a window defined by hits and offset is not well defined and does not apply.

Error handling in searchers:

• Unexpected events: Throw any RuntimeException. This query will fail with the exception message, and the error will be logged
• Expected events: Create (new Result(Query, ErrorMessage) or add result.setErrorIfNoOtherErrors(ErrorMessage) an error message to the Result.
• Recoverable user errors: Add a FeedbackHit explaining the condition and how to correct it.

Specified by:

search in class Searcher

Parameters:

query - the query

Returns:

the result of making this query

getSearchChainsForwarded

public Collection<ForkingSearcher.CommentedSearchChain> getSearchChainsForwarded(SearchChainRegistry registry)

Description copied from class: ForkingSearcher

Returns which searchers this searcher may forward to, for debugging and tracing

Specified by:

getSearchChainsForwarded in class ForkingSearcher

getSourceProperties

public static Properties getSourceProperties(Query query)

Returns the set of properties set for the source or provider given in the query (if any). If the query has not set sourceName or providerName, null will be returned

fill

public void fill(Result result,
                 String summaryClass,
                 Execution execution)

Description copied from class: Searcher

Fill hit properties with data using the given summary class. Calling this on already filled results has no cost.

This needs to be overridden by federating searchers to contact search sources again by propagating the fill call down through the search chain, and by source searchers which talks to fill capable backends to request the data to be filled. Other searchers do not need to override this.

Overrides:

fill in class Searcher

Parameters:

result - the result to fill

summaryClass - the name of the collection of fields to fetch the values of, or null to use the default

defaultSearchChains

public com.yahoo.errorhandling.Results<SearchChainInvocationSpec,UnresolvedSearchChainException> defaultSearchChains(Properties sourceToProviderMap)