solr的facet解读

saundy

　　开发采用更加灵活的solr搜索服务器来实现分层功能。
　　1.QueryResponse类:
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public class QueryResponse extends SolrResponseBase   
{   
  // Direct pointers to known types   
  private NamedList _header = null;   
  private SolrDocumentList _results = null;   
  private NamedList _sortvalues = null;   
  private NamedList _facetInfo = null;   
  private NamedList _debugInfo = null;   
  private NamedList _highlightingInfo = null;   
  private NamedList _spellInfo = null;   
  
  // Facet stuff   
  private Map _facetQuery = null;   
  private List _facetFields = null;   
  private List _limitingFacets = null;   
  private List _facetDates = null;   
  
  // Highlight Info   
  private Map _highlighting = null;   
  
  // SpellCheck Response   
  private SpellCheckResponse _spellResponse = null;   
     
  // Debug Info   
  private Map _debugMap = null;   
  private Map _explainMap = null;   
  
  // utility variable used for automatic binding -- it should not be serialized   
  private transient final SolrServer solrServer;   
//.....   
//.....   
private void extractFacetInfo( NamedList info )   
  {   
    // Parse the queries   
    _facetQuery = new HashMap();   
    NamedList fq = (NamedList) info.get( "facet_queries" );   
    for( Map.Entry entry : fq ) {   
      _facetQuery.put( entry.getKey(), entry.getValue() );   
    }   
      
    // Parse the facet info into fields   
    // TODO?? The list could be  or ?  If always  then we can switch to   
    NamedList ff = (NamedList) info.get( "facet_fields" );   
    if( ff != null ) {   
      _facetFields = new ArrayList( ff.size() );   
      _limitingFacets = new ArrayList( ff.size() );   
         
      long minsize = _results.getNumFound();   
      for( Map.Entry facet : ff ) {   
        FacetField f = new FacetField( facet.getKey() );   
        for( Map.Entry entry : facet.getValue() ) {   
          f.add( entry.getKey(), entry.getValue().longValue() );   
        }   
           
        _facetFields.add( f );   
        FacetField nl = f.getLimitingFields( minsize );   
        if( nl.getValueCount() > 0 ) {   
          _limitingFacets.add( nl );   
        }   
      }   
    }   
      
    //Parse date facets   
    NamedList df = (NamedList) info.get("facet_dates");   
    if (df != null) {   
      // System.out.println(df);   
      _facetDates = new ArrayList( df.size() );   
      for (Map.Entry facet : df) {   
        // System.out.println("Key: " + facet.getKey() + " Value: " + facet.getValue());   
        NamedList values = facet.getValue();   
        String gap = (String) values.get("gap");   
        Date end = (Date) values.get("end");   
        FacetField f = new FacetField(facet.getKey(), gap, end);   
           
        for (Map.Entry entry : values)   {   
          try {   
            f.add(entry.getKey(), Long.parseLong(entry.getValue().toString()));   
          } catch (NumberFormatException e) {   
            //Ignore for non-number responses which are already handled above   
          }   
        }   
           
        _facetDates.add(f);   
      }   
    }   
  }   
}  
public class QueryResponse extends SolrResponseBase
{
  // Direct pointers to known types
  private NamedList _header = null;
  private SolrDocumentList _results = null;
  private NamedList _sortvalues = null;
  private NamedList _facetInfo = null;
  private NamedList _debugInfo = null;
  private NamedList _highlightingInfo = null;
  private NamedList _spellInfo = null;
　　// Facet stuff
  private Map _facetQuery = null;
  private List _facetFields = null;
  private List _limitingFacets = null;
  private List _facetDates = null;
　　// Highlight Info
  private Map _highlighting = null;
　　// SpellCheck Response
  private SpellCheckResponse _spellResponse = null;
  
  // Debug Info
  private Map _debugMap = null;
  private Map _explainMap = null;
　　// utility variable used for automatic binding -- it should not be serialized
  private transient final SolrServer solrServer;
//.....
//.....
private void extractFacetInfo( NamedList info )
  {
    // Parse the queries
    _facetQuery = new HashMap();
    NamedList fq = (NamedList) info.get( "facet_queries" );
    for( Map.Entry entry : fq ) {
      _facetQuery.put( entry.getKey(), entry.getValue() );
    }
   
    // Parse the facet info into fields
    // TODO?? The list could be  or ?  If always  then we can switch to
    NamedList ff = (NamedList) info.get( "facet_fields" );
    if( ff != null ) {
      _facetFields = new ArrayList( ff.size() );
      _limitingFacets = new ArrayList( ff.size() );
      
      long minsize = _results.getNumFound();
      for( Map.Entry facet : ff ) {
        FacetField f = new FacetField( facet.getKey() );
        for( Map.Entry entry : facet.getValue() ) {
          f.add( entry.getKey(), entry.getValue().longValue() );
        }
        
        _facetFields.add( f );
        FacetField nl = f.getLimitingFields( minsize );
        if( nl.getValueCount() > 0 ) {
          _limitingFacets.add( nl );
        }
      }
    }
   
    //Parse date facets
    NamedList df = (NamedList) info.get("facet_dates");
    if (df != null) {
      // System.out.println(df);
      _facetDates = new ArrayList( df.size() );
      for (Map.Entry facet : df) {
        // System.out.println("Key: " + facet.getKey() + " Value: " + facet.getValue());
        NamedList values = facet.getValue();
        String gap = (String) values.get("gap");
        Date end = (Date) values.get("end");
        FacetField f = new FacetField(facet.getKey(), gap, end);
        
        for (Map.Entry entry : values)   {
          try {
            f.add(entry.getKey(), Long.parseLong(entry.getValue().toString()));
          } catch (NumberFormatException e) {
            //Ignore for non-number responses which are already handled above
          }
        }
        
        _facetDates.add(f);
      }
    }
  }
}
　　_facetFields:所有的分层结果  使用 getFacetField(String name) 获得结果
　　_limitingFacets:facetFields中个数大于0的分层，使用getLimitingFacets()返回所有Count个数大于0的FacetField。
　　_facetDates:根据日期的分层结果 getFacetDate(String name)
　　例外，要使用Facet功能，除了设置 Field外，还需要将facet属性设置为true，默认是false的。
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params.set("facet", "true");   
params.set("facet.field", "site_search");   
params.set("facet.field", "kindtag_search");
　　

　　1. FacetField 内嵌了 Count类，Count类保存了被分层出来的的 词 以及该词在搜有搜索出来的文档中出现的次数。
　　
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package org.apache.solr.client.solrj.response;   
  
import java.io.Serializable;   
import java.util.ArrayList;   
import java.util.Date;   
import java.util.List;   
  
import org.apache.solr.client.solrj.util.ClientUtils;   
   
/**  
  * A utility class to hold the facet response.  It could use the NamedList container,  
  * but for JSTL, it is nice to have something that implements List so it can be iterated  
  *   
  * @version $Id: FacetField.java 638357 2008-03-18 13:12:27Z gsingers $  
  * @since solr 1.3  
  */  
public class FacetField implements Serializable   
{   
   public static class Count implements Serializable   
   {   
     private String _name = null;   
     private long _count = 0;   
     // hang onto the FacetField for breadcrumb creation convenience   
     private FacetField _ff = null;   
        
     public Count( FacetField ff, String n, long c )   
     {   
       _name = n;   
       _count = c;   
       _ff = ff;   
     }   
        
     public String getName() {   
       return _name;   
     }   
        
     public void setName( String n )   
     {   
       _name = n;   
     }   
  
     public long getCount() {   
       return _count;   
     }   
        
     public void setCount( long c )   
     {   
       _count = c;   
     }   
        
     public FacetField getFacetField() {   
       return _ff;   
     }   
        
     @Override  
     public String toString()   
     {   
       return _name+" ("+_count+")";   
     }   
        
     public String getAsFilterQuery() {   
       if (_ff.getName().equals("facet_queries")) {   
         return _name;   
       }   
       return   
          ClientUtils.escapeQueryChars( _ff._name ) + ":" +   
          ClientUtils.escapeQueryChars( _name );   
     }   
   }   
      
   private String      _name   = null;   
   private List _values = null;   
   private String _gap = null;   
   private Date _end = null;   
  
//.........   
//.........方法   
  
   }  
package org.apache.solr.client.solrj.response;
　　import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
　　import org.apache.solr.client.solrj.util.ClientUtils;

/**
  * A utility class to hold the facet response.  It could use the NamedList container,
  * but for JSTL, it is nice to have something that implements List so it can be iterated
  *
  * @version $Id: FacetField.java 638357 2008-03-18 13:12:27Z gsingers $
  * @since solr 1.3
  */
public class FacetField implements Serializable
{
   public static class Count implements Serializable
   {
     private String _name = null;
     private long _count = 0;
     // hang onto the FacetField for breadcrumb creation convenience
     private FacetField _ff = null;
     
     public Count( FacetField ff, String n, long c )
     {
       _name = n;
       _count = c;
       _ff = ff;
     }
     
     public String getName() {
       return _name;
     }
     
     public void setName( String n )
     {
       _name = n;
     }
　　public long getCount() {
       return _count;
     }
     
     public void setCount( long c )
     {
       _count = c;
     }
     
     public FacetField getFacetField() {
       return _ff;
     }
     
     @Override
     public String toString()
     {
       return _name+" ("+_count+")";
     }
     
     public String getAsFilterQuery() {
       if (_ff.getName().equals("facet_queries")) {
         return _name;
       }
       return
          ClientUtils.escapeQueryChars( _ff._name ) + ":" +
          ClientUtils.escapeQueryChars( _name );
     }
   }
   
   private String      _name   = null;
   private List _values = null;
   private String _gap = null;
   private Date _end = null;
　　//.........
//.........方法
　　}

　　一个FacetField实例拥有多个Count实例。