package chapter7;

import java.io.IOException;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.Hits;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Sort;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.search.*;

public class LuceneSortExplain {
	static String[] ContentList = { "Lucene 使用 方便", "使用 Lucene","Lucene 功能 強大", "Lucene 開放 源碼" };
	
	public static void main(String[] args) throws IOException{
		searchIndex();
	}
	// 創(chuàng)建索引并通過Explain查看結果排序因子
	private static void searchIndex() throws IOException{   
		try{
			RAMDirectory ramdirectory = new RAMDirectory(); 
			IndexWriter writer = new IndexWriter(ramdirectory,new StandardAnalyzer(),true);
			for (int i = 0; i < ContentList.length; i++)
		    {
		        Document document = new Document(); 

		        Field fieldContent = new Field("Content", ContentList[i], Field.Store.YES, Field.Index.TOKENIZED);
		        document.add(fieldContent);         // 添加創(chuàng)建的文本域到當前文檔
		        writer.addDocument(document);       // 完成的文檔添加到索引
		    }
			writer.close();                         // 關閉索引
		    IndexSearcher searcher = new IndexSearcher(ramdirectory);               // 創(chuàng)建檢索器
		    QueryParser parser = new QueryParser("Content",new StandardAnalyzer()); // 創(chuàng)建查詢分析器
		    Query  query = parser.parse("Lucene");    // 生成查詢對象

		    Hits rstDoc;
		    System.out.println("Lucene相關性排序Explain輸出");
		    System.out.println("-----------------------------------");		    
		    rstDoc = searcher.search(query);     				// Lucene默認相關性排序
		    for (int i = 0; i < rstDoc.length(); i++) 			// 遍歷獲取文檔，并讀取相關參數
		    {
		        Document doc = rstDoc.doc(i);			
		        int id = rstDoc.id( i );

		        System.out.println("檢索結果 " + i +": " + doc.get("Content") + " Boost: " + doc.getBoost() + ", score : " + rstDoc.score(i));
				Explanation exp = searcher.explain( query, id );
				System.out.println( "排序因子 ：" + exp.toString() );
		        
		    }

		    searcher.close();	
		} catch(ParseException e){
			System.out.println("ParseException ");
		} catch(IOException e){
			System.out.println("IOException  ");			
		}
	}
}