Map Entry Transform 

Google Guava is a java library with lot of utilities and reusable components. This requires the library guava-10.0.jar to be in classpath. The following example shows using Maps.transformEntries() API. It transforms the given source map to target map by applying EntryTransformer callback.

File Name  :   com/bethecoder/tutorials/guava/collection_tests/MapEntryTransformTest.java  Author  :   Sudhakar KV Email  :   [email protected]

package com.bethecoder.tutorials.guava.collection_tests; import java.util.Map; import com.google.common.collect.ImmutableMap; import com.google.common.collect.Maps; import com.google.common.collect.Maps.EntryTransformer; public class MapEntryTransformTest {   /**    * @param args    */   public static void main(String[] args) {     Map<String, Integer> immutableMap = ImmutableMap.of("ONE", 1, "TWO", 2, "THREE", 3);     System.out.println(immutableMap);          Map<String, String> transMap =        Maps.transformEntries(immutableMap, new EntryTransformer<String, Integer, String>() {         @Override         public String transformEntry(String key, Integer value) {           return key.toLowerCase() +              "-" + (value * 100); //new value for this key in transformed map         }     });          System.out.println(transMap);   } }

{ONE=1, TWO=2, THREE=3}
{ONE=one-100, TWO=two-200, THREE=three-300}