自定义排序<1>

说明:
  用户会员登陆后,根据该会员属于的类别排序(主要表现在查询产品或其他频道时),这样有助于该会员查到属于自已的东西,分类与当前会员相同的排前

import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.TermDocs;

import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.SortField;
import org.apache.lucene.index.IndexReader;

import org.apache.lucene.search.SortComparatorSource;
import org.apache.lucene.search.ScoreDocComparator;

import java.io.IOException;
import java.util.Map;
import java.util.WeakHashMap;


public class DichanSortExtend implements SortComparatorSource {


public static String[] categorys;
private String category;
private final Map readerCache = new WeakHashMap();
public DichanSortExtend(){ 
}
/*****传入的类别*******/
public DichanSortExtend(String category) {
this.category = category;
}
public void iniCategory(IndexReader reader,String sortname) throws IOException{
final TermEnum enumerator = reader.terms(new Term(sortname, "")); 

categorys = new String[reader.maxDoc()];             
if (categorys.length > 0) {
TermDocs termDocs = reader.termDocs();
try {
if (enumerator.term() == null) {
throw new RuntimeException("no terms in field " + sortname);
}
do {
Term term = enumerator.term();   
if (term.field() != sortname)   
break;
termDocs.seek(enumerator);       
while (termDocs.next()) {        
categorys[termDocs.doc()] = term.text();
}
} while (enumerator.next());

} finally {
termDocs.close();
}
}
}
public ScoreDocComparator newComparator(IndexReader reader, String sortname)
throws IOException {
return new CategoryScoreDocComparator( category);
}
private static class CategoryScoreDocComparator implements ScoreDocComparator {
String category;
public CategoryScoreDocComparator(String category)
{
this.category=category;
}

// 在此处定义自已的排序方式,根据登陆的会员类别，来对检索出的记录进行排序
public int compare(ScoreDoc i, ScoreDoc j) {
if(categorys[i.doc].equals(this.category)){
return 1;
}else if(categorys[j.doc].equals(this.category)){
return -1;
}
return 0;
}
public Comparable sortValue(ScoreDoc data) {
return new String(categorys[data.doc]);
}

public int sortType() {
return SortField.STRING;
}
}


public String toString() {
return "";
}

public static void main(String[] args) throws IOException{
DichanSortExtend sortext = new DichanSortExtend();
System.out.println(sortext.toString());
}
}


Sort sort = new Sort(new SortField("cate",new SortExtendSearch(类别ID)));

并具要初始化