/**
 * Java Collections Framework > TreeMapExample.java
 *
 * Use a TreeMap to store and retrieve objects using keys.  TreeMaps are 
 * slower than HashMaps at retrieval but store their elements in sorted 
 * order.  Note that for ordering to be meaningful, all keys in a TreeMap
 * must be mutually comparable.
 * @author  Feihong Hsu
 */

import java.util.Map;           // Superclass of TreeMap
import java.util.TreeMap;       // A container that supports lookup of values
                                // using keys
import java.util.Iterator;      // Used to traverse the TreeMap

public class TreeMapExample {
    
    // This method prints all the mappings in the given TreeMap object.
    public static void printTreeMap(TreeMap treeMap) {
        System.out.print( "TreeMap: " );
        
        // Use an Iterator to traverse the mappings in the TreeMap.  Note
        // that the mappings are in sorted order (with respect to the keys).
        Iterator iterator = treeMap.entrySet().iterator();
        
        while (iterator.hasNext()) {
            Map.Entry entry = (Map.Entry) iterator.next();
            System.out.print( "(" + entry.getKey() + ": " + 
                              entry.getValue() + "), " );
        }
        System.out.println();
    }
    
    public static void main(String[] args) {
        TreeMap treeMap = new TreeMap();
        
        // Put 4 mappings into the TreeMap.
        treeMap.put("Pharaoh", new Integer(55));
        treeMap.put("Emperor", new Double(2.33));
        treeMap.put("Kaiser", new Long(323322L));
        treeMap.put("Czar", new Boolean(true));
        
        // "TreeMap: (Czar: true), (Emperor: 2.33), (Kaiser: 323322), 
        // (Pharaoh: 55), "
        printTreeMap(treeMap);
        
        // Get the value associate with the key "Emperor"--prints 2.33.
        System.out.println("Value for key Emperor: " + 
                           treeMap.get("Emperor") );
        
        // Remove the mapping with key "Kaiser".
        treeMap.remove("Kaiser");
        
        // TreeMap: (Czar: true), (Emperor: 2.33), (Pharaoh: 55), 
        printTreeMap(treeMap);
        
        // Find out if the TreeMap has the key "Sultan".
        System.out.println( "Has key Sultan? " + 
                            treeMap.containsKey("Sultan") );  // Prints false
    }    
}

/* Output:

TreeMap: (Czar: true), (Emperor: 2.33), (Kaiser: 323322), (Pharaoh: 55), 
Value for key Emperor: 2.33
TreeMap: (Czar: true), (Emperor: 2.33), (Pharaoh: 55), 
Has key Sultan? false

*/