BAEL-965 - CollectionUtil

This commit is contained in:
slavisa-baeldung 2017-06-30 15:53:07 +01:00
parent 69c330eb6c
commit 6f198df9db
3 changed files with 293 additions and 0 deletions

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package com.baeldung.commons.collectionutil;
public class Address {
String locality;
String city;
String zip;
public String getLocality() {
return locality;
}
public void setLocality(String locality) {
this.locality = locality;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append("Address [locality=").append(locality).append(", city=").append(city).append(", zip=").append(zip).append("]");
return builder.toString();
}
public Address(String locality, String city, String zip) {
super();
this.locality = locality;
this.city = city;
this.zip = zip;
}
}

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package com.baeldung.commons.collectionutil;
public class Customer implements Comparable<Customer> {
Integer id;
String name;
Long phone;
String locality;
String city;
String zip;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Long getPhone() {
return phone;
}
public void setPhone(Long phone) {
this.phone = phone;
}
public String getLocality() {
return locality;
}
public void setLocality(String locality) {
this.locality = locality;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getZip() {
return zip;
}
public void setZip(String zip) {
this.zip = zip;
}
public Customer(Integer id, String name, Long phone, String locality, String city, String zip) {
super();
this.id = id;
this.name = name;
this.phone = phone;
this.locality = locality;
this.city = city;
this.zip = zip;
}
public Customer(Integer id, String name, Long phone) {
super();
this.id = id;
this.name = name;
this.phone = phone;
}
public Customer(String name) {
super();
this.name = name;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Customer other = (Customer) obj;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
public int compareTo(Customer o) {
return this.name.compareTo(o.getName());
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append("Customer [id=").append(id).append(", name=").append(name).append(", phone=").append(phone).append("]");
return builder.toString();
}
}

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package com.baeldung.commons.collections;
import com.baeldung.commons.collectionutil.Address;
import com.baeldung.commons.collectionutil.Customer;
import org.apache.commons.collections4.Closure;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.collections4.Predicate;
import org.apache.commons.collections4.Transformer;
import org.junit.Before;
import org.junit.Test;
import java.util.*;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class CollectionUtilsGuideTest {
Customer customer1 = new Customer(1, "Daniel", 123456l, "locality1", "city1", "1234");
Customer customer4 = new Customer(4, "Bob", 456789l, "locality4", "city4", "4567");
List<Customer> list1, list2, list3, linkedList1;
@Before
public void setup() {
Customer customer2 = new Customer(2, "Fredrik", 234567l, "locality2", "city2", "2345");
Customer customer3 = new Customer(3, "Kyle", 345678l, "locality3", "city3", "3456");
Customer customer5 = new Customer(5, "Cat", 567890l, "locality5", "city5", "5678");
Customer customer6 = new Customer(6, "John", 678901l, "locality6", "city6", "6789");
list1 = Arrays.asList(customer1, customer2, customer3);
list2 = Arrays.asList(customer4, customer5, customer6);
list3 = Arrays.asList(customer1, customer2);
linkedList1 = new LinkedList<>(list1);
}
@Test
public void givenList_whenAddIgnoreNull_thenNoNullAdded() {
CollectionUtils.addIgnoreNull(list1, null);
assertFalse(list1.contains(null));
}
@Test
public void givenTwoSortedLists_whenCollated_thenSorted() {
List<Customer> sortedList = CollectionUtils.collate(list1, list2);
assertTrue(sortedList.get(0).getName().equals("Bob"));
assertTrue(sortedList.get(2).getName().equals("Daniel"));
}
@Test
public void givenListOfCustomers_whenTransformed_thenListOfAddress() {
Collection<Address> addressCol = CollectionUtils.collect(list1, new Transformer<Customer, Address>() {
public Address transform(Customer customer) {
return new Address(customer.getLocality(), customer.getCity(), customer.getZip());
}
});
List<Address> addressList = new ArrayList<Address>(addressCol);
assertTrue(addressList.size() == 3);
assertTrue(addressList.get(0).getLocality().equals("locality1"));
}
@Test
public void givenCustomerList_whenCountMatches_thenCorrect() {
int result = CollectionUtils.countMatches(list1, customer -> Arrays.asList("Daniel","Kyle").contains(customer.getName()));
assertTrue(result == 2);
}
@Test
public void givenCustomerList_WhenFiltered_thenCorrectSize() {
boolean isModified = CollectionUtils.filter(linkedList1, customer -> Arrays.asList("Daniel","Kyle").contains(customer.getName()));
//filterInverse does the opposite. It removes the element from the list if the Predicate returns true
//select and selectRejected work the same way except that they do not remove elements from the given collection and return a new collection
assertTrue(isModified && linkedList1.size() == 2);
}
@Test
public void givenCustomerList_whenForAllDoSetNameNull_thenNameNull() {
CollectionUtils.forAllDo(list1, customer -> {
customer.setName(null);
});
// forAllButLast does the same except for the last element in the collection
assertTrue(list1.get(0).getName() == null);
}
@Test
public void givenNonEmptyList_whenCheckedIsNotEmpty_thenTrue() {
List<Customer> emptyList = new ArrayList<Customer>();
List<Customer> nullList = null;
//Very handy at times where we want to check if a collection is not null and not empty too.
//isNotEmpty does the opposite. Handy because using ! operator on isEmpty makes it missable while reading
assertTrue(CollectionUtils.isNotEmpty(list1));
assertTrue(CollectionUtils.isEmpty(nullList));
assertTrue(CollectionUtils.isEmpty(emptyList));
}
@Test
public void givenCustomerListAndASubcollection_whenChecked_thenTrue() {
assertTrue(CollectionUtils.isSubCollection(list3, list1));
}
@Test
public void givenTwoLists_whenIntersected_thenCheckSize() {
Collection<Customer> intersection = CollectionUtils.intersection(list1, list3);
assertTrue(intersection.size() == 2);
}
@Test
public void givenTwoLists_whenSubtracted_thenCheckElementNotPresentInA() {
Collection<Customer> result = CollectionUtils.subtract(list1, list3);
assertFalse(result.contains(customer1));
}
@Test
public void givenTwoLists_whenUnioned_thenCheckElementPresentInResult() {
Collection<Customer> union = CollectionUtils.union(list1, list2);
assertTrue(union.contains(customer1));
assertTrue(union.contains(customer4));
}
}