Re: hash map / collection choice

On 4/27/2014 12:58 PM, Philipp Kraus wrote:


If you'd prefer a set, I'd just make one. It isn't that much trouble to
do so. The implementation might be a little slow, but if it gives you
trouble then you just have to optimize it more. Most time code like
this won't be the bottle-neck.

Not tested. I've renamed your get method to "findById", and you'll need
a proper hash/equals method, one that compares all fields in MyEdge, for
this to work 100%.

package quicktest;

import java.util.AbstractSet;
import java.util.HashMap;
import java.util.Iterator;

public class MySet extends AbstractSet<MyEdge>
{
    private final HashMap<Integer,MyEdge> map = new HashMap<>();

    @Override
    public Iterator iterator() {
       return map.values().iterator();
    }

    @Override
    public int size() {
       return map.size();
    }

    @Override
    public boolean add( MyEdge edge ) { // edge @NotNull
       MyEdge temp = map.get( edge.getID() );
       map.put( edge.getID(), edge);
       return !edge.equals( temp );
    }

    public MyEdge findById( int id ) {
       return map.get(id);
    }
}

// Dummy for compilation
class MyEdge{
   public int getID() {return 0;}
}