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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.handler;

import org.apache.solr.common.params.SolrParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.search.DisMaxQParserPlugin;
import org.apache.solr.search.QueryParsing;
import org.apache.solr.util.SolrPluginUtils;

import java.net.MalformedURLException;
import java.net.URL;

/**
 * 
 * A Generic query plugin designed to be given a simple query expression
 * from a user, which it will then query against a variety of
 * pre-configured fields, in a variety of ways, using BooleanQueries,
 * DisjunctionMaxQueries, and PhraseQueries.
 * 
 *
 * 
 * All of the following options may be configured for this plugin
 * in the solrconfig as defaults, and may be overriden as request parameters
 * 
 *
 * 
 * q.alt - An alternate query to be used in cases where the main
 *             query (q) is not specified (or blank).  This query should
 *             be expressed in the Standard SolrQueryParser syntax (you
 *             can use q.alt=*:* to denote that all documents
 *             should be returned when no query is specified)
 * 
 * tie - (Tie breaker) float value to use as tiebreaker in
 *           DisjunctionMaxQueries (should be something much less than 1)
 * 
 *  qf - (Query Fields) fields and boosts to use when building
 *           DisjunctionMaxQueries from the users query.  Format is:
 *           "fieldA^1.0 fieldB^2.2".
 *           This param can be specified multiple times, and the fields
 *           are additive.
 * 
 *  mm - (Minimum Match) this supports a wide variety of
 *           complex expressions.
 *           read {@link SolrPluginUtils#setMinShouldMatch SolrPluginUtils.setMinShouldMatch} and mm expression format for details.
 * 
 *  pf - (Phrase Fields) fields/boosts to make phrase queries out
 *           of, to boost the users query for exact matches on the specified fields.
 *           Format is: "fieldA^1.0 fieldB^2.2".
 *           This param can be specified multiple times, and the fields
 *           are additive.
 * 
 *  ps - (Phrase Slop) amount of slop on phrase queries built for pf
 *           fields.
 * 
 *  qs - (Query Slop) amount of slop on phrase queries explicitly
 *           specified in the "q" for qf fields.
 * 
 *  bq - (Boost Query) a raw lucene query that will be included in the 
 *           users query to influence the score.  If this is a BooleanQuery
 *           with a default boost (1.0f), then the individual clauses will be
 *           added directly to the main query.  Otherwise, the query will be
 *           included as is.
 *           This param can be specified multiple times, and the boosts are 
 *           are additive.  NOTE: the behaviour listed above is only in effect
 *           if a single bq paramter is specified.  Hence you can
 *           disable it by specifying an additional, blank, bq 
 *           parameter.
 * 
 *  bf - (Boost Functions) functions (with optional boosts) that will be
 *           included in the users query to influence the score.
 *           Format is: "funcA(arg1,arg2)^1.2
 *           funcB(arg3,arg4)^2.2".  NOTE: Whitespace is not allowed
 *           in the function arguments.
 *           This param can be specified multiple times, and the functions
 *           are additive.
 * 
 *  fq - (Filter Query) a raw lucene query that can be used
 *           to restrict the super set of products we are interested in - more
 *           efficient then using bq, but doesn't influence score.
 *           This param can be specified multiple times, and the filters
 *           are additive.
 * 
 * 
 *
 * 
 * The following options are only available as request params...
 * 
 *
 * 
 *    q - (Query) the raw unparsed, unescaped, query from the user.
 * 
 * sort - (Order By) list of fields and direction to sort on.
 * 
 * 
 *
 *  * :TODO: document facet param support
 *
 * 
 * @deprecated use StandardRequestHandler with a "defType=dismax" param
 */
@Deprecated
public class DisMaxRequestHandler extends StandardRequestHandler  
{

  @Override
  public void init(NamedList args) {
    super.init( args );
    NamedList def = null;
    
    // redo "defaults"
    Object o = args.get("defaults");
    if (o != null && o instanceof NamedList) {
      def = (NamedList)o;
    } else {
      // no explict defaults list, use all args implicitly
      // indexOf so " is valid indicator of no defaults
      def = args;
    }
    
    //  Make the default query type "dismax" if not specified
    if (def.get(QueryParsing.DEFTYPE) == null) {
      def = def.clone();
      def.add(QueryParsing.DEFTYPE, DisMaxQParserPlugin.NAME);
      defaults = SolrParams.toSolrParams( def );
    }
  }

	//////////////////////// SolrInfoMBeans methods //////////////////////

	@Override
	public String getDescription() {
	    return "DisjunctionMax Request Handler: Does relevancy based queries "
	       + "across a variety of fields using configured boosts";
	}

	@Override
	public String getVersion() {
	    return "$Revision: 630746 $";
	}

	@Override
	public String getSourceId() {
	  return "$Id: DisMaxRequestHandler.java 630746 2008-02-25 07:02:09Z hossman $";
	}

	@Override
	public String getSource() {
	  return "$URL: https://svn.apache.org/repos/asf/lucene/solr/branches/branch-1.4/src/java/org/apache/solr/handler/DisMaxRequestHandler.java $";
	}
  
  @Override
  public URL[] getDocs() {
    try {
    return new URL[] { new URL("http://wiki.apache.org/solr/DisMaxRequestHandler") };
    }
    catch( MalformedURLException ex ) { return null; }
  }
}