Sorting an Array of Objects throws long[] error

Question

Im following the MKyong sort examples .

I have the class AGRinformesActivos overriding compareTo() method to sort my class by riesgoTotal double.

public class AGRinformesActivos extends EntidadBase implements Comparable<AGRinformesActivos>{

private static final long   serialVersionUID    = -4341418821044868087L;

private String                  tipoActivo          = "";
private String                  codigo              = "";
private String                  denominacion        = "";
private int                     idAmenaza           = 0;
private double                  impactoTotal        = 0;
private double                  riesgoTotal         = 0;
private int                     valorPendiente      = 0;
ArrayList<Double>               impactoCuali        = new ArrayList<Double>();
ArrayList<String>               impactoCuanti       = new ArrayList<String>();
ArrayList<Double>               riesgoCuali         = new ArrayList<Double>();
ArrayList<String>               riesgoCuanti        = new ArrayList<String>();

To order in asc Im using this compareTo() version: Sort array of object by particular member inside the object/class .

public int compareTo(AGRinformesActivos o) {
    return new Double(this.riesgoTotal).compareTo(new Double(o.riesgoTotal));
}

And this is my code:

    ArrayList <AGRinformesActivos> datosTotal = new ArrayList<AGRinformesActivos>();
    List listadoActTotal = manager.dameListadoActivos( Integer.parseInt(info.getIdtipoActivo().trim()), info.getCodigo().trim());
for( Object o : listadoActTotal ) {
                fila = (List) o;                    
                String codigoActivo = fila.get( 0 ).toString();             
                // If exists we obtain, if not exists we create.
                if (activosDimension.containsKey( codigoActivo )){
                    // If exists, obtain from activosDimension
                    informesActivo = activosDimension.get( codigoActivo );
                }else{
                    informesActivo = new AGRinformesActivos();
                    activosDimension.put( codigoActivo, informesActivo );
                    // Al objeto le añado tipoActivo, idActivo y Denominación
                    String tipoActivo = manager.dameNombreTipoActivo(info.getIdtipoActivo());
                    informesActivo.setTipoActivo( tipoActivo );
                    informesActivo.setCodigo( codigoActivo );
                    informesActivo.setDenominacion( fila.get( 1 ).toString() );
                    }
                    // Add impactoTotal and riesgoTotal
                    informesActivo.setImpactoTotal( Double.parseDouble( fila.get( 2 ).toString() ) );
                    informesActivo.setRiesgoTotal( Double.parseDouble(fila.get( 3 ).toString() ) );
                }

                informesActivo.getImpactoCuali().add( Double.parseDouble(fila.get( 5 ).toString() ) );
                informesActivo.getRiesgoCuali().add( Double.parseDouble(fila.get( 6 ).toString() ) );

                String gradoImp = dameRangoEconGrado(Double.parseDouble(fila.get( 5 ).toString() ));
                String gradoRiesg = dameRangoEconGrado(Double.parseDouble(fila.get( 6 ).toString() ));              
                if(gradoImp.equals("") ){
                    gradoImp = dameRangoEconGrado(1);
                }
                informesActivo.getImpactoCuanti().add( gradoImp );
                if(gradoRiesg.equals( "" )){
                    gradoRiesg = dameRangoEconGrado(1);
                }
                informesActivo.getRiesgoCuanti().add( gradoRiesg );

                if (!datosTotaltemp.contains( informesActivo )){
                    datosTotaltemp.add( informesActivo );
                    datosTotal.add( informesActivo );
                }
            }
Arrays.sort(datosTotal);

...

When the code reach to Arrays.sort(datosTotal); throws the error:

The method sort(long[]) in the type Arrays is not applicable for the arguments (ArrayList<AGRinformesActivos>)
] con causa raíz
java.lang.Error: Unresolved compilation problem: 
    The method sort(long[]) in the type Arrays is not applicable for the arguments (ArrayList<AGRinformesActivos>)

    at com.dominion.procop.agr.struts.actions.AGRInformes.buscarActivosEmpty(AGRInformes.java:270)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

What am i doing wrong? AGRinformesActivos has a static long. is this the problem? why? in my compareTo im using the double of riesgoTotal .

Thank you in advance

Answer 1

You are sorting a Collection, not an array. Try Collections.sort() instead of Arrays.sort() .

Answer 2

your datosTotal reference is a collection, not an array. So you shouldn't use Arrays to sort it, but rather Collections.sort .

For efficiency's sake, I'd also recommend that you use

public int compareTo(AGRinformesActivos o) {
    return Double.compare(this.riesgoTotal,o.riesgoTotal);
}

Rather than creating two new Double objects for every comparison.

Answer 3

Arrays.sort can not sort an ArrayList. Try to use Collections.sort