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

Thursday 5 February 2015

Java : Collection Framework : TreeMap (TailMap Inclusive)

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TreeMapExample.java

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

/*
 * Example of tailMap(K fromKey, 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 greater than
         * (or equal to, if inclusive is true) fromKey. 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.tailMap(20, false);

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

        sortedMap = treeMap.tailMap(20, true);

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

    }
}

Output

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

sortedMap [inclusive is false] : {30=Apple, 40=Ball, 50=Dog}

sortedMap [inclusive is true] : {20=Eagle, 30=Apple, 40=Ball, 50=Dog}