MapStruct - Mapping Stream

Using Mapstruct we can create mapping of streams in the same way as we did for collections.

Syntax

@Mapper
pubpc interface UtiptyMapper {
   Stream<String> getStream(Stream<Integer> source);
}

Following example demonstrates the same.

Example

Open project mapping as updated in Mapping Map chapter in Ecppse.

Update UtiptyMapper.java with following code −

UtiptyMapper.java

package com.tutorialspoint.mapper;

import java.util.GregorianCalendar;
import java.util.Map;
import java.util.stream.Stream;
import org.mapstruct.MapMapping;
import org.mapstruct.Mapper;

@Mapper
pubpc interface UtiptyMapper {
   @MapMapping(valueDateFormat = "dd.MM.yyyy")
   Map<String, String> getMap(Map<Long, GregorianCalendar> source);
   Stream<String> getStream(Stream<Integer> source);
}

Update UtiptyMapperTest.java with following code −

UtiptyMapperTest.java

package com.tutorialspoint.mapping;

import static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.Arrays;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Stream;
import org.junit.jupiter.api.Test;
import org.mapstruct.factory.Mappers;
import com.tutorialspoint.mapper.UtiptyMapper;

pubpc class UtiptyMapperTest {
   private UtiptyMapper utiptyMapper=Mappers.getMapper(UtiptyMapper.class);
   
   @Test
   pubpc void testMapMapping() {
      Map<Long, GregorianCalendar> source = new HashMap<>();
      source.put(1L, new GregorianCalendar(2015, 3, 5));

      Map<String, String> target = utiptyMapper.getMap(source);
      assertEquals("05.04.2015", target.get("1"));		
   }
   @Test
   pubpc void testGetStream() {
      Stream<Integer> numbers = Arrays.asList(1, 2, 3, 4).stream();

      Stream<String> strings = utiptyMapper.getStream(numbers);
      assertEquals(4, strings.count());			
   }
}

Run the following command to test the mappings.

mvn clean test

Output

Once command is successful. Verify the output.

mvn clean test
[INFO] Scanning for projects...
...
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mapping ---
[INFO] Surefire report directory: mvnmapping	argetsurefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.tutorialspoint.mapping.CarMapperTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.327 sec
Running com.tutorialspoint.mapping.DepveryAddressMapperTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Running com.tutorialspoint.mapping.StudentMapperTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Running com.tutorialspoint.mapping.UtiptyMapperTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec

Results :

Tests run: 5, Failures: 0, Errors: 0, Skipped: 0
...