finished

src/main/java/com/zipcoder/payment/Check.java

@@ -60,7 +60,7 @@ public class Check implements Payment {
     @Override
     public String getShortDescription() {
 
-        return "Check " + this.getPayerName() + " ****" + this.getAccountNumber().substring(this.getAccountNumber().length() - 4);
+        return "Check " + this.getPayerName() + " ***" + this.getAccountNumber().substring(this.getAccountNumber().length() - 4);
     }
 
     public void setId(Long l) {

src/main/java/com/zipcoder/payment/PaymentPresenter.java

@@ -1,6 +1,81 @@
 package com.zipcoder.payment;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+
 public class PaymentPresenter {
+    PaymentSortByPayer sorter;
+
+    public PaymentPresenter() {
+        sorter = new PaymentSortByPayer();
+    }
+
+    public String toString(Payment[] payments) {
+
+        String s = "";
+        StringBuilder sb = new StringBuilder();
+
+        if (payments.length > 0) {
+            Payment temp = payments[0];
+
+            for (int i = 0; i < payments.length; i++) {
+                for (int j = 0; j < payments.length - i - 1; j++) {
+                    if (sorter.compare(payments[j], payments[j + 1]) > 0) {
+                        temp = payments[j];
+                        payments[j] = payments[j + 1];
+                        payments[j + 1] = temp;
+                    }
+                }
+            }
+        } else {
+            return s;
+        }
+
+        for (int i = 0; i < payments.length; i++) {
+            sb.append(payments[i].getShortDescription() + "\n");
+        }
+
+        return sb.toString();
+    }
+
+    public String toStringByPayerName(Payment[] payments) {
+
+        String s = "";
+        StringBuilder sb = new StringBuilder();
 
+        ArrayList<Payment> sortedPayment;
+        if (payments.length > 0) {
 
+            sortedPayment = new ArrayList<>(Arrays.asList(payments));
+            Collections.sort(sortedPayment, Comparator.comparing(Payment::getPayerName));
+
+        } else {
+            return s;
+        }
+
+        return sortedString(sortedPayment);
+    }
+
+    public String toStringById(Payment[] payments) {
+
+        StringBuilder sb = new StringBuilder();
+        ArrayList<Payment> payments1 = new ArrayList<>(Arrays.asList(payments));
+        Collections.sort(payments1, Comparator.comparingLong(Payment::getId));
+
+        return sortedString(payments1);
+    }
+
+    public String sortedString (ArrayList<Payment> p) {
+        StringBuilder sb = new StringBuilder();
+
+        for (Payment pm : p) {
+            sb.append(pm.getShortDescription() + "\n");
+        }
+
+        return sb.toString();
+    }
 }
+
+

src/main/java/com/zipcoder/payment/PaymentSortByPayer.java

@@ -9,4 +9,8 @@ public class PaymentSortByPayer implements Comparator<Payment> {
         return o1.compareTo(o2);
     }
 
+    public int compareByPayerName(String s1, String s2) {
+        return s1.compareTo(s2);
+    }
+
 }

src/test/java/com/zipcoder/payment/PaymentPresenterTest.java

@@ -1,4 +1,67 @@
 package com.zipcoder.payment;
 
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
 public class PaymentPresenterTest {
+
+    @Test
+    public void testNoPayments() {
+        Payment[] payments = new Payment[0];
+        PaymentPresenter presenter = new PaymentPresenter();
+        String expected = "";
+
+        String actual = presenter.toString(payments);
+
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testMultiplePaymentSort() {
+        Payment[] payments = new Payment[2];
+        Payment paypal = new PayPal(4L, "Tia Mowry", "tia@mowry.com");
+        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551");
+
+        payments[0] = paypal;
+        payments[1] = check;
+
+        PaymentPresenter presenter = new PaymentPresenter();
+        String expected = "Check Tia Mowry ***4551\nPayPal Tia Mowry tia@mowry.com\n";
+
+        String actual = presenter.toString(payments);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testMultiPayersName() {
+        Payment[] payments = new Payment[2];
+        Payment paypal = new PayPal(4L, "Tamara Mowry", "tamara@mowry.com");
+        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551");
+
+        payments[0] = paypal;
+        payments[1] = check;
+
+        PaymentPresenter presenter = new PaymentPresenter();
+        String expected = "PayPal Tamara Mowry tamara@mowry.com\nCheck Tia Mowry ***4551\n";
+
+        String actual = presenter.toStringByPayerName(payments);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void testLambaId() {
+        Payment[] payments = new Payment[2];
+        Payment paypal = new PayPal(120L, "Tamara Mowry", "tamara@mowry.com");
+        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551");
+
+        payments[0] = paypal;
+        payments[1] = check;
+
+        PaymentPresenter presenter = new PaymentPresenter();
+        String expected = "Check Tia Mowry ***4551\nPayPal Tamara Mowry tamara@mowry.com\n";
+
+        String actual = presenter.toStringById(payments);
+        assertEquals(expected, actual);
+    }
 }