JAVA EE: Java : Collection Framework : TreeMap (HeadMap Inclusive)

Thursday, 5 February 2015

Java : Collection Framework : TreeMap (HeadMap Inclusive)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=Raxit9-FluA&list=UUhwKlOVR041tngjerWxVccw

TreeMapExample.java

import java.util.SortedMap;
import java.util.TreeMap;

/*
 * Example of headMap(K toKey,boolean inclusive) method.
 */
public class TreeMapExample
{
    public static void main( String[] args )
    {

        TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>();

        treeMap.put(10, "Cat");
        treeMap.put(50, "Dog");
        treeMap.put(30, "Apple");
        treeMap.put(40, "Ball");
        treeMap.put(20, "Eagle");

        System.out.println("treeMap : " + treeMap + "\n");

        /*
         * Returns a view of the portion of this map whose keys are less than
         * (or equal to, if inclusive is true) toKey. The returned map is backed
         * by this map, so changes in the returned map are reflected in this
         * map, and vice-versa. The returned map supports all optional map
         * operations that this map supports.
         */
        SortedMap<Integer, String> sortedMap = treeMap.headMap(40, false);

        System.out.println("sortedMap [inclusive is false] : " + sortedMap
                + "\n");

        sortedMap = treeMap.headMap(40, true);

        System.out.println("sortedMap [inclusive is true] : " + sortedMap
                + "\n");

    }
}

Output

treeMap : {10=Cat, 20=Eagle, 30=Apple, 40=Ball, 50=Dog}

sortedMap [inclusive is false] : {10=Cat, 20=Eagle, 30=Apple}

sortedMap [inclusive is true] : {10=Cat, 20=Eagle, 30=Apple, 40=Ball}