AbstractSortedMap.java

import java.util.Comparator;

public abstract class AbstractSortedMap<K, V> extends AbstractMap<K, V> implements SortedMap<K, V>{
    
    private Comparator<K> comp;
    
    protected AbstractSortedMap(Comparator<K> c){
        comp = c;
    } 
    protected AbstractSortedMap(){
        this(new DefaultComparator<K>());
    }

    protected int compare(Entry<K, V> a, Entry<K, V> b){
        return comp.compare(a.getKey(), b.getKey());
    }
    protected int compare(K a, Entry<K, V> b){
        return comp.compare(a, b.getKey());
    }
    protected int compare(Entry<K, V> a, K b){
        return comp.compare(a.getKey(), b);
    }
    protected int compare(K a, K b){
        return comp.compare(a, b);
    }

    protected boolean checkKey(K key) throws IllegalArgumentException{
        try{
            return (comp.compare(key, key) == 0);
        }catch(ClassCastException e){
            throw new IllegalArgumentException("Incompatible key");    
        }
    }
}