com.yahoo.search.querytransform

Class QueryCombinator

java.lang.Object

com.yahoo.component.AbstractComponent

com.yahoo.component.chain.ChainedComponent

com.yahoo.processing.Processor

com.yahoo.search.Searcher

com.yahoo.search.querytransform.QueryCombinator

All Implemented Interfaces:

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

public class QueryCombinator
extends Searcher

A searcher which grabs query parameters of the form "defidx.(identifier)=(index name)" and "query.(identifier)=(user query)", * parses them and adds them as AND items to the query root.

If the given default index does not exist in the search definition, the query part will be parsed with the settings of the default index set to the "".

Author:

Steinar Knutsen

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	QueryCombinator.QueryPart

Field Summary

Fields

Modifier and Type	Field and Description
private static String	QUERYPREFIX

Fields inherited from class com.yahoo.component.AbstractComponent

isDeconstructable

Constructor Summary

Constructors

Constructor and Description
QueryCombinator(com.yahoo.component.ComponentId id)

Method Summary

Modifier and Type	Method and Description
private static void	addAndItem(QueryTree queryTree, Item item)
private void	addAndItems(Query query, Iterable<QueryCombinator.QueryPart> pieces, Execution.Context context)
private static void	assignDefaultIndex(Item item, String defaultIndex)
private static Set<QueryCombinator.QueryPart>	findQuerySnippets(Properties properties)
private static boolean	hasDots(String name)
Result	search(Query query, Execution execution) Override this to implement your searcher.

Methods inherited from class com.yahoo.search.Searcher

ensureFilled, fill, 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

QUERYPREFIX

private static final String QUERYPREFIX

See Also:

Constant Field Values

Constructor Detail

QueryCombinator

public QueryCombinator(com.yahoo.component.ComponentId id)

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

addAndItems

private void addAndItems(Query query,
                         Iterable<QueryCombinator.QueryPart> pieces,
                         Execution.Context context)

addAndItem

private static void addAndItem(QueryTree queryTree,
                               Item item)

assignDefaultIndex

private static void assignDefaultIndex(Item item,
                                       String defaultIndex)

findQuerySnippets

private static Set<QueryCombinator.QueryPart> findQuerySnippets(Properties properties)

hasDots

private static boolean hasDots(String name)