diff --git a/core-java-collections-list/src/main/java/com/baeldung/collection/filtering/Employee.java b/core-java-collections-list/src/main/java/com/baeldung/collection/filtering/Employee.java new file mode 100644 index 0000000000..2aa267b4dc --- /dev/null +++ b/core-java-collections-list/src/main/java/com/baeldung/collection/filtering/Employee.java @@ -0,0 +1,44 @@ +package com.baeldung.collection.filtering; + +/** + * Java 8 Collection Filtering by List of Values base class. + * + * @author Rodolfo Felipe + */ +public class Employee { + + private Integer employeeNumber; + private String name; + private Integer departmentId; + + public Employee(Integer employeeNumber, String name, Integer departmentId) { + this.employeeNumber = employeeNumber; + this.name = name; + this.departmentId = departmentId; + } + + public Integer getEmployeeNumber() { + return employeeNumber; + } + + public void setEmployeeNumber(Integer employeeNumber) { + this.employeeNumber = employeeNumber; + } + + public String getName() { + return name; + } + + public void setName(String name) { + this.name = name; + } + + public Integer getDepartmentId() { + return departmentId; + } + + public void setDepartmentId(Integer departmentId) { + this.departmentId = departmentId; + } + +} diff --git a/core-java-collections-list/src/test/java/com/baeldung/collection/filtering/CollectionFilteringUnitTest.java b/core-java-collections-list/src/test/java/com/baeldung/collection/filtering/CollectionFilteringUnitTest.java new file mode 100644 index 0000000000..cbc7136192 --- /dev/null +++ b/core-java-collections-list/src/test/java/com/baeldung/collection/filtering/CollectionFilteringUnitTest.java @@ -0,0 +1,73 @@ +package com.baeldung.collection.filtering; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.List; +import java.util.Set; +import java.util.stream.Collectors; + +import org.hamcrest.Matchers; +import org.junit.Assert; +import org.junit.Test; + +/** + * Various filtering examples. + * + * @author Rodolfo Felipe + */ +public class CollectionFilteringUnitTest { + + private List buildEmployeeList() { + return Arrays.asList(new Employee(1, "Mike", 1), new Employee(2, "John", 1), new Employee(3, "Mary", 1), new Employee(4, "Joe", 2), new Employee(5, "Nicole", 2), new Employee(6, "Alice", 2), new Employee(7, "Bob", 3), new Employee(8, "Scarlett", 3)); + } + + private List employeeNameFilter() { + return Arrays.asList("Alice", "Mike", "Bob"); + } + + @Test + public void givenEmployeeList_andNameFilterList_thenObtainFilteredEmployeeList_usingForEachLoop() { + List filteredList = new ArrayList<>(); + List originalList = buildEmployeeList(); + List nameFilter = employeeNameFilter(); + + for (Employee employee : originalList) { + for (String name : nameFilter) { + if (employee.getName() + .equalsIgnoreCase(name)) { + filteredList.add(employee); + } + } + } + + Assert.assertThat(filteredList.size(), Matchers.is(nameFilter.size())); + } + + @Test + public void givenEmployeeList_andNameFilterList_thenObtainFilteredEmployeeList_usingLambda() { + List filteredList; + List originalList = buildEmployeeList(); + List nameFilter = employeeNameFilter(); + + filteredList = originalList.stream() + .filter(employee -> nameFilter.contains(employee.getName())) + .collect(Collectors.toList()); + + Assert.assertThat(filteredList.size(), Matchers.is(nameFilter.size())); + } + + @Test + public void givenEmployeeList_andNameFilterList_thenObtainFilteredEmployeeList_usingLambdaAndHashSet() { + List filteredList; + List originalList = buildEmployeeList(); + Set nameFilterSet = employeeNameFilter().stream() + .collect(Collectors.toSet()); + + filteredList = originalList.stream() + .filter(employee -> nameFilterSet.contains(employee.getName())) + .collect(Collectors.toList()); + + Assert.assertThat(filteredList.size(), Matchers.is(nameFilterSet.size())); + } + +}