如何在java中使用布尔和日期对PriorityQueue进行排序

Question

如何对PriorityQueue进行排序，使所有具有“true”值的bool对象始终位于顶部，其他位置的底部为false值，并按日期。

import java.text.DateFormat; 
import java.util.*; 

import static java.text.DateFormat.*; 
import static java.util.Locale.*; 

public class Patient implements Comparable<Patient> { 

    private String name; 
    private Date termin; 
    private boolean emergency; 

    Patient(String name, Date termin, boolean emergency) { 
     this.name = name; 
     this.termin = termin; 
     this.emergency = emergency; 
    } 

    public String getName(){ 
     return name; 
    } 

    @Override 
    public String toString() 
    { 

     if (emergency) 
     { 
      return "** Notfall! ** \t "+ this.name; 
     } 
     else 
     { 
      DateFormat df = getDateInstance(SHORT, GERMANY); 
      DateFormat tf = DateFormat.getTimeInstance(SHORT,GERMANY); 
      return df.format(this.termin)+" "+tf.format(this.termin)+" \t "+this.name; 
     } 

    } 

    @Override 
    public int compareTo(Patient o) { 
     int i = 0;/* 
     if (this.equals(null)|| o.equals(null)) 
     { 
      i= 0; 
     } 

     if (this.emergency == o.emergency) 
     { 
      if(this.termin.getTime() < o.termin.getTime()){ 
       i=1; 
      }else{ 
       i= -1; 
      } 
     } 
     if (this.emergency || o.emergency) 
     { 
      i= -1; 
     } 


     return i;*/ 
    } 
} 

结果： （不正确排序）

Warteschlange: 

at.htl.WaitingRoom@5cad8086 

Nächster Patient: ** Notfall! **  Ralph 

Nächster Patient: ** Notfall! **  anonym 

Nächster Patient: 21.10.11 09:15  Antonia Adam 

Nächster Patient: 21.10.11 08:30  Cäcilia Chlum 

Nächster Patient: 21.10.11 09:30  Bert Bauer 

结果应该是这样的：

Warteschlange：

at.htl.WaitingRoom@5cad8086 

Nächster Patient: ** Notfall! **  Ralph 

Nächster Patient: ** Notfall! **  anonym 

Nächster Patient: 21.10.11 08:30  Cäcilia Chlum 

Nächster Patient: 21.10.11 09:15  Antonia Adam 

Nächster Patient: 21.10.11 09:30  Bert Bauer 

Answer 1

你想通过紧急情况第一排序，按日期排序：

@Override 
public int compareTo(Patient o) { 
    if(emergency && !o.emergency) 
     return -1; 
    if(!emergency && o.emergency) 
     return 1; 
    // at this point emergency == o.emergency 
    // since Java 7 you can return Long.compare(termin.getTime(), o.termin.getTime()) instead of the following: 
    if(termin.getTime() < o.termin.getTime()) 
     return -1; 
    if(termin.getTime() > o.termin.getTime()) 
     return 1; 
    return 0; 
}