Java PriorityQueue实现类lucene段合并

Java自带 PriorityQueue实现类lucene段合并，当需要自定义比较器的时候没有Lucene自实现的PriorityQueue好用.

 

1.封装类型 Book

package com.taobao.terminator.allen.LuceneTest; public class Book { private String name; private int id; private String owner; public Book (String name, String owner, int id) { this.name = name; this.owner = owner; this.id = id; } public String getOwner() { return owner; } public void setOwner(String owner) { this.owner = owner; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getId() { return id; } public void setId(int id) { this.id = id; } }  

 

2.比较器

import java.util.Comparator; import java.util.List; public class AllenComparator implements Comparator<List<Book>>{ /** * 比较二个List的大小，以第一个元素的姓名值作比较 */ public int compare(List<Book> o1, List<Book> o2) { return o1.get(0).getName().compareTo(o2.get(0).getName()); } } 

 

 

3.PriorityQueue代码测试

import java.util.ArrayList; import java.util.Comparator; import java.util.List; import java.util.PriorityQueue; public class PriorityQueueTest { private List<Book> list1 ; private List<Book> list2 ; private List<Book> list3 ; public PriorityQueueTest (){ this.list1 = new ArrayList<Book>(); this.list2 = new ArrayList<Book>(); this.list3 = new ArrayList<Book>(); initData(list1, list2, list3); } private void initData(List<Book> list1, List<Book> list2, List<Book> list3) { generatorData(list1, "owner-1", 1); generatorData(list2, "owner-2", 2); generatorData(list3, "owner-3", 3); } /** * 生成List数据集 * @param list * @param i 相同数据重复次数 */ private void generatorData(List<Book> list, String owner, int i) { int k = 0; while(k < i) { list.add(new Book("name-ini" + i, owner, k)); k++; } } public static void main(String[] args) { PriorityQueueTest test = new PriorityQueueTest(); Comparator<List<Book>> comparator = new AllenComparator(); PriorityQueue<List<Book>> queue = new PriorityQueue<List<Book>>(3, comparator); PriorityQueue<List<Book>> matchQueue = new PriorityQueue<List<Book>>(3, comparator); queue.add(test.list1); queue.add(test.list2); queue.add(test.list3); while(!queue.isEmpty()) { List<Book> list = queue.poll(); matchQueue.add(list); System.out.println("name--->" + list.get(0).getName() + " owner--->" + list.get(0).getOwner() + " id--->" + list.get(0).getId()); List<Book> cList = queue.peek(); while (cList != null && list.get(0).getName().equals(cList.get(0).getName())) { List<Book> nlist = queue.poll(); matchQueue.add(nlist); System.out.println("name--->" + nlist.get(0).getName() + " owner--->" + nlist.get(0).getOwner() + " id--->" + nlist.get(0).getId()); cList = queue.peek(); } //matchingQueue while(matchQueue.size() > 0) { List<Book> mList = matchQueue.poll(); mList.remove(0); if(mList.size() > 0) { queue.add(mList); } } } } }  

 

4.结果输出

 

 name--->name-ini1 owner--->owner-1 id--->0 name--->name-ini2 owner--->owner-2 id--->0 name--->name-ini2 owner--->owner-2 id--->1 name--->name-ini3 owner--->owner-3 id--->0 name--->name-ini3 owner--->owner-3 id--->1 name--->name-ini3 owner--->owner-3 id--->2