Problem using ArrayList

[Fernando Piovani]

hi folks, iam having trouble using the method add from ArrayList.

My program consists in parsing and loading information from a xml file containing gps coordinates to memory.

while(element.getNodeName().equals("nd"))
                    {
                        atr=element.getAttributeNode("ref");
                        for (j=0;j<list.getLength();j++)
                        {
                            element = (Element)list.item(j);
                            if (element.getNodeName().equals("node"))
                            {
                                aux=element.getAttributeNode("id");
                                if (atr.getTextContent().equals(aux.getTextContent()))
                                {
                                    nd.setId(Long.parseLong(aux.getTextContent()));
                                    aux=element.getAttributeNode("lat");
                                    nd.setLat(Double.parseDouble(aux.getTextContent()));
                                    aux=element.getAttributeNode("lon");
                                    nd.setLon(Double.parseDouble(aux.getTextContent()));
                                    System.out.println("Lat: "+nd.getLat());
                                    via.getId().add(nd);
                                    break;
                                }
                            }
                        }
                        i++;
                        element = (Element)list.item(i);
                    }

Where 'nd' is a object of a class Nodes. And 'via' from Way class:

class Nodes{
    private long id;
    private double lat,lon;}

class Way {
    
    private String name;
    private ArrayList<Nodes> id = new ArrayList();
    private long ref;}

So a way its composed of several nodes (if its not a straight line). The problem of the code is that should load a way to the memory, along with its nodes. But for some reason, the add method of ArrayList its only adding the last element of the nodes list.

System.out.println(via.getId().get(0).getLat());
        System.out.println(via.getId().get(1).getLat());
        System.out.println(via.getId().get(2).getLat());
        System.out.println(via.getId().get(3).getLat());

With this xml example:

<?xml version="1.0" encoding="UTF-8"?>
<osm version="0.6" generator="CGImap 0.0.2">
 <bounds minlat="-21.7904200" minlon="-46.5641770" maxlat="-21.7874960" maxlon="-46.5612100"/>
 <node id="1206927179" lat="-21.7909981" lon="-46.5630399" user="TByte" uid="379585" visible="true" version="1" changeset="7591818" timestamp="2011-03-18T04:08:36Z"/>
 <node id="1394135210" lat="-21.7883913" lon="-46.5615064" user="Fernando Piovani" uid="504246" visible="true" version="1" changeset="8980674" timestamp="2011-08-10T21:04:03Z"/>
 <node id="1394135212" lat="-21.7883908" lon="-46.5609906" user="Fernando Piovani" uid="504246" visible="true" version="1" changeset="8980674" timestamp="2011-08-10T21:04:03Z"/>
 <node id="1394135215" lat="-21.7879178" lon="-46.5609903" user="Fernando Piovani" uid="504246" visible="true" version="1" changeset="8980674" timestamp="2011-08-10T21:04:03Z"/> 
 <node id="1394135206" lat="-21.7879189" lon="-46.5615087" user="Fernando Piovani" uid="504246" visible="true" version="1" changeset="8980674" timestamp="2011-08-10T21:04:02Z"/>

 <way id="125549487" user="Fernando Piovani" uid="504246" visible="true" version="1" changeset="8980674" timestamp="2011-08-10T21:04:03Z">
  <nd ref="1394135206"/>
  <nd ref="1394135210"/>
  <nd ref="1394135212"/>
  <nd ref="1394135215"/>
  <tag k="name" v="Teste 2"/>	
 </way>
</osm>

So the exit of the program goes as:

Lat: -21.7879189
Lat: -21.7883913
Lat: -21.7883908
Lat: -21.7879178
-21.7879178
-21.7879178
-21.7879178
-21.7879178

When it should goes like this:

Lat: -21.7879189
Lat: -21.7883913
Lat: -21.7883908
Lat: -21.7879178
-21.7879189
-21.7883913
-21.7883908
-21.7879178


What is wrong?

[Paul Clapham]

It looks like you are using the same object repeatedly, instead of creating a new object for each set of data. My guess would be the variable named "nd".

[Fernando Piovani]

Paul Clapham wrote:It looks like you are using the same object repeatedly, instead of creating a new object for each set of data. My guess would be the variable named "nd".

yeah, i've used nd=new Nodes(); under the .add method and it works. Thanks for poiting that out dude.