How i use PriorityQueue in Java with class ?

Question

I have these class

public class Datos {
private String Nombre;
private String Telefono;
private int Prioridad;


public Datos(String Nombre, String Telefono, int Prioridad)
{
    this.Nombre = Nombre;
    this.Telefono = Telefono;
    this.Prioridad = Prioridad;

}

public String getNombre() {
    return Nombre;
}

public String getTelefono() {
    return Telefono;
}

public int getPrioridad() {
    return Prioridad;
}

public void setNombre(String Nombre) {
    this.Nombre = Nombre;
}

public void setTelefono(String Telefono) {
    this.Telefono = Telefono;
}

public void setPrioridad(int Prioridad) {
    this.Prioridad = Prioridad;
}

}

And i want to accommodate the customers with the Priority. We have 4 categories 1,2,3,4 and i want to acommodate with the PriorityQueue

Vincent · Accepted Answer · 2015-05-10 22:33:11Z

2

You'll want to make your class Datos implement Comparable. This tells java that the objects can be compared. Then define a compareTo method in Datos. This method should return a number > 0 if this > d, equal to 0 if this == d, and < 0 if this < d:

public int compareTo(Datos d) {
    return priority - d.priority;
}

You can then declare a new PriorityQueue<Datos> and add the objects in.

answered May 10, 2015 at 22:33

Vincent

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4 Comments

Saul Ramirez Over a year ago

Where i remote call the method compareTo ? I don't know where. It's my fisrt time to use PriorityQueue

Vincent Over a year ago

@SaulRamirez You don't have to call compareTo yourself. The PriorityQueue will call that to find what order to sort the objects in.

Saul Ramirez Over a year ago

The System have and exception "proyectosegundoqueue.Datos cannot be cast to java.lang.Comparable" at at java.util.PriorityQueue.siftUpComparable(PriorityQueue.java:652) at java.util.PriorityQueue.siftUp(PriorityQueue.java:647) at java.util.PriorityQueue.offer(PriorityQueue.java:344) at java.util.PriorityQueue.add(PriorityQueue.java:321)

Vincent Over a year ago

do you have public class Datos implements Comparable<Datos>?

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