How to sort a PriorityQueue with bool and date in java - priority-queue

Question

How can you sort a PriorityQueue that all object with a bool with a 'true' value will be always on the top and the other with false value at the bottom and sorted with the date.
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;*/
}
}
RESULT:
(is not sorted right )
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
The result should be like this:
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

You want to first sort by emergencies, second by date:
#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;
}