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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.query.rewrite;
import com.yahoo.component.chain.Chain;
import com.yahoo.component.chain.dependencies.After;
import com.yahoo.component.chain.dependencies.Provides;
import com.yahoo.search.*;
import com.yahoo.search.searchchain.Execution;
import com.yahoo.component.ComponentId;
import java.util.logging.Logger;
/**
* Execute rewriter search chain specified by the user.
* It's inteneded to be used for executing rewriter search chains
* for different markets.
*
* @author Karen Sze Wing Lee
*/
@Provides("SearchChainDispatcher")
@After("QLAS")
public class SearchChainDispatcherSearcher extends Searcher {
protected final Logger logger = Logger.getLogger(SearchChainDispatcherSearcher.class.getName());
/**
* Constructor for this searcher
* @param id Component ID (see vespa's search container doc for more detail)
*/
public SearchChainDispatcherSearcher(ComponentId id) {
super(id);
}
/**
* Constructor for unit test
*/
public SearchChainDispatcherSearcher() {
}
/**
* Execute another search chain specified by the user<br>
* - Retrieve search chain specified by the user through
* param<br>
* - Execute specified search chain if exist
*/
@Override
public Result search(Query query, Execution execution) {
RewriterUtils.log(logger, query, "Entering SearchChainDispatcherSearcher");
// Retrieve search chain specified by user through REWRITER_CHAIN
String rewriterChain = RewriterUtils.getRewriterChain(query);
// Skipping to next searcher if no rewriter chain is specified
if(rewriterChain==null || rewriterChain.equals("")) {
RewriterUtils.log(logger, query, "No rewriter chain is specified, " +
"skipping to the next searcher");
return execution.search(query);
}
// Execute rewriter search chain
RewriterUtils.log(logger, query, "Redirecting to chain " + rewriterChain);
Chain<Searcher> myChain = execution.searchChainRegistry().getChain(rewriterChain);
if(myChain==null) {
RewriterUtils.log(logger, query, "Invalid search chain specified, " +
"skipping to the next searcher");
return execution.search(query);
}
new Execution(myChain, execution.context()).search(query);
RewriterUtils.log(logger, query, "Finish executing search chain " + rewriterChain);
// Continue down the chain ignoring the result from REWRITER_CHAIN
// since the rewriters only modify the query but not the result
return execution.search(query);
}
}
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