killbill-aplcache

Details

diff --git a/api/src/main/java/com/ning/billing/invoice/api/Invoice.java b/api/src/main/java/com/ning/billing/invoice/api/Invoice.java
index 9f21b11..bf7fd7b 100644
--- a/api/src/main/java/com/ning/billing/invoice/api/Invoice.java
+++ b/api/src/main/java/com/ning/billing/invoice/api/Invoice.java
@@ -57,7 +57,9 @@ public interface Invoice extends Entity {
 
     BigDecimal getAmountPaid();
 
-    BigDecimal getTotalAmount();
+    BigDecimal getAmountCharged();
+
+    BigDecimal getAmountCredited();
 
     BigDecimal getBalance();
 
diff --git a/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoice.java b/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoice.java
index 0de9aa4..952ff60 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoice.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoice.java
@@ -173,18 +173,24 @@ public class DefaultInvoice extends EntityBase implements Invoice {
     }
 
     @Override
-    public BigDecimal getTotalAmount() {
-        return invoiceItems.getTotalAmount();
+    public BigDecimal getAmountCharged() {
+        return invoiceItems.getAmountCharged();
+    }
+
+    @Override
+    public BigDecimal getAmountCredited() {
+        return invoiceItems.getAmountCredited();
     }
 
     @Override
     public BigDecimal getBalance() {
-        return getTotalAmount().subtract(getAmountPaid());
+        // credits offset payments
+        return getAmountCharged().subtract(getAmountPaid().subtract(getAmountCredited()));
     }
 
     @Override
     public boolean isDueForPayment(final DateTime targetDate, final int numberOfDays) {
-        if (getTotalAmount().compareTo(BigDecimal.ZERO) == 0) {
+        if (getBalance().compareTo(BigDecimal.ZERO) == 0) {
             return false;
         }
 
diff --git a/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoiceGenerator.java b/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoiceGenerator.java
index 8f4554d..08e19c0 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoiceGenerator.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/model/DefaultInvoiceGenerator.java
@@ -97,17 +97,9 @@ public class DefaultInvoiceGenerator implements InvoiceGenerator {
         removeCancellingInvoiceItems(existingItems);
         removeDuplicatedInvoiceItems(proposedItems, existingItems);
 
-        for (InvoiceItem existingItem : existingItems) {
-            if (existingItem instanceof RecurringInvoiceItem) {
-                RecurringInvoiceItem recurringItem = (RecurringInvoiceItem) existingItem;
-                proposedItems.add(recurringItem.asReversingItem());
-            }
-        }
-
-        BigDecimal creditAmount = calculateCreditAmountToUse(existingItems, proposedItems);
-        if (creditAmount.compareTo(BigDecimal.ZERO) > 0) {
-            proposedItems.add(new CreditInvoiceItem(invoiceId, accountId, clock.getUTCNow(), creditAmount.negate(), targetCurrency));
-        }
+        addReversingItems(existingItems, proposedItems);
+        generateCreditsForPastRepairedInvoices(accountId, existingInvoices, proposedItems, targetCurrency);
+        consumeExistingCredit(invoiceId, accountId, existingItems, proposedItems, targetCurrency);
 
         if (proposedItems == null || proposedItems.size() == 0) {
             return null;
@@ -118,54 +110,75 @@ public class DefaultInvoiceGenerator implements InvoiceGenerator {
         }
     }
 
-    private BigDecimal calculateCreditAmountToUse(List<InvoiceItem> existingItems, List<InvoiceItem> proposedItems) {
-        BigDecimal totalUnusedCreditAmount = BigDecimal.ZERO;
-        for (InvoiceItem item : existingItems) {
-            if (item instanceof CreditInvoiceItem) {
-                totalUnusedCreditAmount = totalUnusedCreditAmount.add(item.getAmount());
+    private void generateCreditsForPastRepairedInvoices(UUID accountId, List<Invoice> existingInvoices, List<InvoiceItem> proposedItems, Currency currency) {
+        // determine most accurate invoice balances up to this point
+        Map<UUID, BigDecimal> amountOwedByInvoice = new HashMap<UUID, BigDecimal>();
+
+        if (existingInvoices != null) {
+            for (Invoice invoice : existingInvoices) {
+                amountOwedByInvoice.put(invoice.getId(), invoice.getBalance());
             }
         }
 
-        BigDecimal totalAmountOwed = BigDecimal.ZERO;
         for (InvoiceItem item : proposedItems) {
-            // there should be no credit items proposed at this point, but remove them anyhow
-            if (!(item instanceof CreditInvoiceItem)) {
-                totalAmountOwed = totalAmountOwed.add(item.getAmount());
+            UUID invoiceId = item.getInvoiceId();
+            if (amountOwedByInvoice.containsKey(invoiceId)) {
+                amountOwedByInvoice.put(invoiceId, amountOwedByInvoice.get(invoiceId).add(item.getAmount()));
+            } else {
+                amountOwedByInvoice.put(invoiceId, item.getAmount());
             }
         }
 
-        if (totalUnusedCreditAmount.compareTo(BigDecimal.ZERO) == 0) {
-            return BigDecimal.ZERO;
-        } else {
-            if (totalAmountOwed.compareTo(totalUnusedCreditAmount) > 0) {
-                return totalUnusedCreditAmount;
-            } else {
-                return totalAmountOwed;
+        for (UUID invoiceId : amountOwedByInvoice.keySet()) {
+            BigDecimal invoiceBalance = amountOwedByInvoice.get(invoiceId);
+            if (invoiceBalance.compareTo(BigDecimal.ZERO) < 0) {
+                proposedItems.add(new CreditInvoiceItem(invoiceId, accountId, clock.getUTCNow(), invoiceBalance.negate(), currency));
             }
         }
     }
 
-    @Override
-    public void distributeItems(List<Invoice> invoices) {
-        Map<UUID, Invoice> invoiceMap = new HashMap<UUID, Invoice>();
-
-        for (Invoice invoice : invoices) {
-            invoiceMap.put(invoice.getId(), invoice);
+    private void addReversingItems(List<InvoiceItem> existingItems, List<InvoiceItem> proposedItems) {
+        for (InvoiceItem existingItem : existingItems) {
+            if (existingItem instanceof RecurringInvoiceItem) {
+                RecurringInvoiceItem recurringItem = (RecurringInvoiceItem) existingItem;
+                proposedItems.add(recurringItem.asReversingItem());
+            }
         }
+    }
 
-        for (final Invoice invoice: invoices) {
-            Iterator<InvoiceItem> itemIterator = invoice.getInvoiceItems().iterator();
-            final UUID invoiceId = invoice.getId();
+    private void consumeExistingCredit(UUID invoiceId, UUID accountId, List<InvoiceItem> existingItems,
+                                       List<InvoiceItem> proposedItems, Currency targetCurrency) {
+        BigDecimal totalUnusedCreditAmount = BigDecimal.ZERO;
+        BigDecimal totalAmountOwed = BigDecimal.ZERO;
 
-            while (itemIterator.hasNext()) {
-                InvoiceItem item = itemIterator.next();
+        for (InvoiceItem item : existingItems) {
+            if (item instanceof CreditInvoiceItem) {
+                totalUnusedCreditAmount = totalUnusedCreditAmount.add(item.getAmount());
+            }
+        }
 
-                if (!item.getInvoiceId().equals(invoiceId)) {
-                    invoiceMap.get(item.getInvoiceId()).addInvoiceItem(item);
-                    itemIterator.remove();
-                }
+        for (InvoiceItem item : proposedItems) {
+            if (item instanceof CreditInvoiceItem) {
+                totalUnusedCreditAmount = totalUnusedCreditAmount.add(item.getAmount());
+            } else {
+                totalAmountOwed = totalAmountOwed.add(item.getAmount());
             }
         }
+
+        // credits are positive when they reduce the amount owed (since they offset payment)
+        // the credit balance should never be negative
+        BigDecimal creditAmount = BigDecimal.ZERO;
+        if (totalUnusedCreditAmount.compareTo(BigDecimal.ZERO) > 0) {
+            if (totalAmountOwed.abs().compareTo(totalUnusedCreditAmount.abs()) > 0) {
+                creditAmount = totalUnusedCreditAmount.negate();
+            } else {
+                creditAmount = totalAmountOwed;
+            }
+        }
+
+        if (creditAmount.compareTo(BigDecimal.ZERO) < 0) {
+            proposedItems.add(new CreditInvoiceItem(invoiceId, accountId, clock.getUTCNow(), creditAmount, targetCurrency));
+        }
     }
 
     private void validateTargetDate(DateTime targetDate) throws InvoiceApiException {
diff --git a/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceGenerator.java b/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceGenerator.java
index e1c7e00..0b47099 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceGenerator.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceGenerator.java
@@ -31,6 +31,4 @@ import com.ning.billing.junction.api.BillingEventSet;
 public interface InvoiceGenerator {
     public Invoice generateInvoice(UUID accountId, @Nullable BillingEventSet events, @Nullable List<Invoice> existingInvoices,
                                    DateTime targetDate, Currency targetCurrency) throws InvoiceApiException;
-
-    public void distributeItems(List<Invoice> invoices);
 }
diff --git a/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceItemList.java b/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceItemList.java
index 683bbaf..357c7a8 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceItemList.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/model/InvoiceItemList.java
@@ -34,55 +34,33 @@ public class InvoiceItemList extends ArrayList<InvoiceItem> {
         this.addAll(invoiceItems);
     }
 
-    public BigDecimal getTotalAmount() {
+    public BigDecimal getAmountCharged() {
         // naive implementation, assumes all invoice items share the same currency
         BigDecimal total = BigDecimal.ZERO.setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
 
         for (final InvoiceItem item : this) {
-            if (item.getAmount() != null) {
-                total = total.add(item.getAmount());
+            if (!(item instanceof CreditInvoiceItem)) {
+                if (item.getAmount() != null) {
+                    total = total.add(item.getAmount());
+                }
             }
         }
 
         return total.setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
     }
 
-//    public void removeCancellingPairs() {
-//        List<InvoiceItem> itemsToRemove = new ArrayList<InvoiceItem>();
-//
-//        for (int firstItemIndex = 0; firstItemIndex < this.size(); firstItemIndex++) {
-//            for (int secondItemIndex = firstItemIndex + 1; secondItemIndex < this.size(); secondItemIndex++) {
-//                InvoiceItem firstItem = this.get(firstItemIndex);
-//                InvoiceItem secondItem = this.get(secondItemIndex);
-//                if (firstItem.cancels(secondItem)) {
-//                    itemsToRemove.add(firstItem);
-//                    itemsToRemove.add(secondItem);
-//                }
-//            }
-//        }
-//
-//        this.removeAll(itemsToRemove);
-//    }
+    public BigDecimal getAmountCredited() {
+        // naive implementation, assumes all invoice items share the same currency
+        BigDecimal total = BigDecimal.ZERO.setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
+
+        for (final InvoiceItem item : this) {
+            if (item instanceof CreditInvoiceItem) {
+                if (item.getAmount() != null) {
+                    total = total.add(item.getAmount());
+                }
+            }
+        }
 
-//   /*
-//    * removes recurring items from the list that have a recurring amount of zero, but a recurring rate that is not zero
-//    */
-//    public void cleanupDuplicatedItems() {
-//        Iterator<InvoiceItem> iterator = this.iterator();
-//        while (iterator.hasNext()) {
-//            InvoiceItem item = iterator.next();
-//
-//            if (item instanceof RecurringInvoiceItem) {
-//                RecurringInvoiceItem that = (RecurringInvoiceItem) item;
-//                boolean recurringRateNull = (that.getRate() == null);
-//                boolean recurringAmountZero = (that.getAmount() !=null) && (that.getAmount().compareTo(BigDecimal.ZERO) == 0);
-//
-//                if (recurringRateNull || recurringAmountZero) {
-//                    iterator.remove();
-//                } else if (that.getEndDate() != null && that.getStartDate().compareTo(that.getEndDate()) == 0) {
-//                    iterator.remove();
-//                }
-//            }
-//        }
-//    }
+        return total.setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
+    }
 }
diff --git a/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceFormatter.java b/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceFormatter.java
index ed50d2e..1ca7824 100644
--- a/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceFormatter.java
+++ b/invoice/src/main/java/com/ning/billing/invoice/template/formatters/DefaultInvoiceFormatter.java
@@ -120,8 +120,13 @@ public class DefaultInvoiceFormatter implements InvoiceFormatter {
     }
 
     @Override
-    public BigDecimal getTotalAmount() {
-        return invoice.getTotalAmount();
+    public BigDecimal getAmountCharged() {
+        return invoice.getAmountCharged();
+    }
+
+    @Override
+    public BigDecimal getAmountCredited() {
+        return invoice.getAmountCredited();
     }
 
     @Override
diff --git a/invoice/src/test/java/com/ning/billing/invoice/dao/InvoiceDaoTests.java b/invoice/src/test/java/com/ning/billing/invoice/dao/InvoiceDaoTests.java
index e47e152..97d7532 100644
--- a/invoice/src/test/java/com/ning/billing/invoice/dao/InvoiceDaoTests.java
+++ b/invoice/src/test/java/com/ning/billing/invoice/dao/InvoiceDaoTests.java
@@ -80,7 +80,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         assertTrue(thisInvoice.getInvoiceDate().compareTo(invoiceDate) == 0);
         assertEquals(thisInvoice.getCurrency(), Currency.USD);
         assertEquals(thisInvoice.getNumberOfItems(), 0);
-        assertTrue(thisInvoice.getTotalAmount().compareTo(BigDecimal.ZERO) == 0);
+        assertTrue(thisInvoice.getBalance().compareTo(BigDecimal.ZERO) == 0);
     }
 
     @Test
@@ -100,7 +100,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
 
         Invoice savedInvoice = invoiceDao.getById(invoiceId);
         assertNotNull(savedInvoice);
-        assertEquals(savedInvoice.getTotalAmount().compareTo(new BigDecimal("21.00")), 0);
+        assertEquals(savedInvoice.getBalance().compareTo(new BigDecimal("21.00")), 0);
         assertEquals(savedInvoice.getBalance().compareTo(new BigDecimal("21.00")), 0);
         assertEquals(savedInvoice.getAmountPaid(), BigDecimal.ZERO);
         assertEquals(savedInvoice.getInvoiceItems().size(), 1);
@@ -113,7 +113,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         Invoice retrievedInvoice = invoiceDao.getById(invoiceId);
         assertNotNull(retrievedInvoice);
         assertEquals(retrievedInvoice.getInvoiceItems().size(), 1);
-        assertEquals(retrievedInvoice.getTotalAmount().compareTo(new BigDecimal("21.00")), 0);
+        assertEquals(retrievedInvoice.getAmountCharged().compareTo(new BigDecimal("21.00")), 0);
         assertEquals(retrievedInvoice.getBalance().compareTo(new BigDecimal("10.00")), 0);
         assertEquals(retrievedInvoice.getAmountPaid().compareTo(new BigDecimal("11.00")), 0);
     }
@@ -447,10 +447,10 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         invoiceDao.create(invoice2, context);
 
         Invoice savedInvoice1 = invoiceDao.getById(invoice1.getId());
-        assertEquals(savedInvoice1.getTotalAmount(), ZERO);
+        assertEquals(savedInvoice1.getBalance(), ZERO);
 
         Invoice savedInvoice2 = invoiceDao.getById(invoice2.getId());
-        assertEquals(savedInvoice2.getTotalAmount(), FIFTEEN);
+        assertEquals(savedInvoice2.getBalance(), FIFTEEN);
     }
 
     @Test
@@ -475,7 +475,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
 
         // expect one pro-ration item and one full-period item
         assertEquals(invoice.getNumberOfItems(), 2);
-        assertEquals(invoice.getTotalAmount().compareTo(ZERO), 0);
+        assertEquals(invoice.getBalance().compareTo(ZERO), 0);
     }
 
     private Subscription getZombieSubscription() {
@@ -513,7 +513,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         Invoice invoice1 = generator.generateInvoice(accountId, events, null, effectiveDate1, Currency.USD);
         assertNotNull(invoice1);
         assertEquals(invoice1.getNumberOfItems(), 1);
-        assertEquals(invoice1.getTotalAmount().compareTo(ZERO), 0);
+        assertEquals(invoice1.getBalance().compareTo(ZERO), 0);
 
         List<Invoice> invoiceList = new ArrayList<Invoice>();
         invoiceList.add(invoice1);
@@ -527,7 +527,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         Invoice invoice2 = generator.generateInvoice(accountId, events, invoiceList, effectiveDate2, Currency.USD);
         assertNotNull(invoice2);
         assertEquals(invoice2.getNumberOfItems(), 1);
-        assertEquals(invoice2.getTotalAmount().compareTo(cheapAmount), 0);
+        assertEquals(invoice2.getBalance().compareTo(cheapAmount), 0);
 
         invoiceList.add(invoice2);
 
@@ -535,7 +535,7 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         Invoice invoice3 = generator.generateInvoice(accountId, events, invoiceList, effectiveDate3, Currency.USD);
         assertNotNull(invoice3);
         assertEquals(invoice3.getNumberOfItems(), 1);
-        assertEquals(invoice3.getTotalAmount().compareTo(cheapAmount), 0);
+        assertEquals(invoice3.getBalance().compareTo(cheapAmount), 0);
     }
 
     @Test
@@ -578,14 +578,14 @@ public class InvoiceDaoTests extends InvoiceDaoTestBase {
         Invoice invoice = generator.generateInvoice(UUID.randomUUID(), events, null, effectiveDate2, Currency.USD);
         assertNotNull(invoice);
         assertEquals(invoice.getNumberOfItems(), 2);
-        assertEquals(invoice.getTotalAmount().compareTo(cheapAmount), 0);
+        assertEquals(invoice.getBalance().compareTo(cheapAmount), 0);
 
         invoiceDao.create(invoice, context);
         Invoice savedInvoice = invoiceDao.getById(invoice.getId());
 
         assertNotNull(savedInvoice);
         assertEquals(savedInvoice.getNumberOfItems(), 2);
-        assertEquals(savedInvoice.getTotalAmount().compareTo(cheapAmount), 0);
+        assertEquals(savedInvoice.getBalance().compareTo(cheapAmount), 0);
     }
 
     @Test
diff --git a/invoice/src/test/java/com/ning/billing/invoice/MockBillingEventSet.java b/invoice/src/test/java/com/ning/billing/invoice/MockBillingEventSet.java
index 3ab1f0d..80db3b8 100644
--- a/invoice/src/test/java/com/ning/billing/invoice/MockBillingEventSet.java
+++ b/invoice/src/test/java/com/ning/billing/invoice/MockBillingEventSet.java
@@ -30,7 +30,11 @@ public class MockBillingEventSet extends TreeSet<BillingEvent> implements Billin
 
     private boolean isAccountInvoiceOff;
     private List<UUID> subscriptionIdsWithAutoInvoiceOff = new ArrayList<UUID>();
-    
+
+    public void addSubscriptionWithAutoInvoiceOff(UUID subscriptionId) {
+        subscriptionIdsWithAutoInvoiceOff.add(subscriptionId);
+    }
+
     @Override
     public boolean isLast(BillingEvent event) {
         return isAccountInvoiceOff;
@@ -46,4 +50,7 @@ public class MockBillingEventSet extends TreeSet<BillingEvent> implements Billin
         return subscriptionIdsWithAutoInvoiceOff;
     }
 
+    public void clearSubscriptionsWithAutoInvoiceOff() {
+        subscriptionIdsWithAutoInvoiceOff.clear();
+    }
 }
diff --git a/invoice/src/test/java/com/ning/billing/invoice/tests/DefaultInvoiceGeneratorTests.java b/invoice/src/test/java/com/ning/billing/invoice/tests/DefaultInvoiceGeneratorTests.java
index bf63662..54dae8c 100644
--- a/invoice/src/test/java/com/ning/billing/invoice/tests/DefaultInvoiceGeneratorTests.java
+++ b/invoice/src/test/java/com/ning/billing/invoice/tests/DefaultInvoiceGeneratorTests.java
@@ -19,11 +19,15 @@ package com.ning.billing.invoice.tests;
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertNotNull;
 import static org.testng.Assert.assertNull;
+import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;
 
 import java.math.BigDecimal;
 import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
 
 import javax.annotation.Nullable;
@@ -128,7 +132,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         assertNotNull(invoice);
         assertEquals(invoice.getNumberOfItems(), 2);
-        assertEquals(invoice.getTotalAmount(), TWENTY);
+        assertEquals(invoice.getBalance(), TWENTY);
         assertEquals(invoice.getInvoiceItems().get(0).getSubscriptionId(), sub.getId());
     }
 
@@ -167,7 +171,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         BigDecimal expectedNumberOfBillingCycles;
         expectedNumberOfBillingCycles = ONE.add(FOURTEEN.divide(THIRTY_ONE, 2 * NUMBER_OF_DECIMALS, ROUNDING_METHOD));
         BigDecimal expectedAmount = expectedNumberOfBillingCycles.multiply(rate).setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
-        assertEquals(invoice.getTotalAmount(), expectedAmount);
+        assertEquals(invoice.getBalance(), expectedAmount);
     }
 
     @Test
@@ -196,7 +200,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         assertNotNull(invoice);
         assertEquals(invoice.getNumberOfItems(), 2);
-        assertEquals(invoice.getTotalAmount(), rate1.add(rate2).setScale(NUMBER_OF_DECIMALS));
+        assertEquals(invoice.getBalance(), rate1.add(rate2).setScale(NUMBER_OF_DECIMALS));
     }
 
     @Test
@@ -233,7 +237,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         expectedValue = expectedValue.add(numberOfCyclesEvent2.multiply(rate2));
         expectedValue = expectedValue.setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
 
-        assertEquals(invoice.getTotalAmount(), expectedValue);
+        assertEquals(invoice.getBalance(), expectedValue);
     }
 
     @Test
@@ -264,7 +268,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         assertNotNull(invoice);
         assertEquals(invoice.getNumberOfItems(), 4);
-        assertEquals(invoice.getTotalAmount(), rate1.add(rate2).add(TWO.multiply(rate3)).setScale(NUMBER_OF_DECIMALS));
+        assertEquals(invoice.getBalance(), rate1.add(rate2).add(TWO.multiply(rate3)).setScale(NUMBER_OF_DECIMALS));
     }
 
     @Test
@@ -293,6 +297,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         assertNull(invoice2);
     }
 
+    // TODO: modify this test to keep a running total of expected invoice amount over time
     @Test
     public void testMultiplePlansWithUtterChaos() throws InvoiceApiException, CatalogApiException {
         // plan 1: change of phase from trial to discount followed by immediate cancellation; (covers phase change, cancel, pro-ration)
@@ -376,7 +381,8 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         // on 4/29/2011, cancel subscription 1
         events.add(createBillingEvent(subscriptionId1, plan1CancelDate, plan1, plan1Phase3, 5));
-        expectedAmount = TWELVE.multiply(SIX.divide(THIRTY, NUMBER_OF_DECIMALS, ROUNDING_METHOD)).negate().setScale(NUMBER_OF_DECIMALS);
+        // previous invoices are adjusted; this is the pro-ration amount only
+        expectedAmount = TWELVE.multiply(TWENTY_FOUR.divide(THIRTY, NUMBER_OF_DECIMALS, ROUNDING_METHOD)).setScale(NUMBER_OF_DECIMALS);
         testInvoiceGeneration(accountId, events, invoices, plan1CancelDate, 2, expectedAmount);
 
         // on 5/10/2011, invoice subscription 2 (trial)
@@ -421,8 +427,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         // on 7/31/2011, convert subscription 3 to annual
         events.add(createBillingEvent(subscriptionId3, plan3UpgradeToAnnualDate, plan3, plan3Phase2, 31));
-        expectedAmount = ONE_HUNDRED.subtract(TEN);
-        expectedAmount = expectedAmount.add(TEN.multiply(ELEVEN.divide(THIRTY_ONE, 2 * NUMBER_OF_DECIMALS, ROUNDING_METHOD)));
+        expectedAmount = ONE_HUNDRED.add(TEN.multiply(ELEVEN.divide(THIRTY_ONE, 2 * NUMBER_OF_DECIMALS, ROUNDING_METHOD)));
         expectedAmount = expectedAmount.setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD);
         testInvoiceGeneration(accountId, events, invoices, plan3UpgradeToAnnualDate, 3, expectedAmount);
 
@@ -446,7 +451,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         // on 10/7/2011, invoice subscription 4 (plan 2), cancel subscription 5
         events.add(createBillingEvent(subscriptionId5, plan5CancelDate, plan5, plan5Phase2, 10));
-        expectedAmount = TWENTY_FOUR.add(TWENTY.multiply(THREE.divide(THIRTY)).negate().setScale(NUMBER_OF_DECIMALS));
+        expectedAmount = TWENTY_FOUR.add(TWENTY.multiply(TWENTY_SEVEN.divide(THIRTY)).setScale(NUMBER_OF_DECIMALS));
         testInvoiceGeneration(accountId, events, invoices, plan5CancelDate, 3, expectedAmount);
 
         // on 10/10/2011, invoice plan 2 (evergreen)
@@ -545,7 +550,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice1 = generator.generateInvoice(accountId, events, null, startDate, Currency.USD);
         assertNotNull(invoice1);
         assertEquals(invoice1.getNumberOfItems(), 2);
-        assertEquals(invoice1.getTotalAmount(), FIFTEEN);
+        assertEquals(invoice1.getBalance(), FIFTEEN);
 
         List<Invoice> invoiceList = new ArrayList<Invoice>();
         invoiceList.add(invoice1);
@@ -557,7 +562,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice2 = generator.generateInvoice(accountId, events, invoiceList, currentDate, Currency.USD);
         assertNotNull(invoice2);
         assertEquals(invoice2.getNumberOfItems(), 1);
-        assertEquals(invoice2.getTotalAmount(), FIVE);
+        assertEquals(invoice2.getBalance(), FIVE);
     }
 
     @Test
@@ -581,7 +586,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice1 = generator.generateInvoice(accountId, events, null, startDate, Currency.USD);
         assertNotNull(invoice1);
         assertEquals(invoice1.getNumberOfItems(), 1);
-        assertEquals(invoice1.getTotalAmount(), fixedCost1);
+        assertEquals(invoice1.getBalance(), fixedCost1);
 
         List<Invoice> invoiceList = new ArrayList<Invoice>();
         invoiceList.add(invoice1);
@@ -595,11 +600,11 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice2 = generator.generateInvoice(accountId, events, invoiceList, phaseChangeDate, Currency.USD);
         assertNotNull(invoice2);
         assertEquals(invoice2.getNumberOfItems(), 1);
-        assertEquals(invoice2.getTotalAmount(), fixedCost2);
+        assertEquals(invoice2.getBalance(), fixedCost2);
     }
 
     @Test
-    public void testNutsFailure() throws InvoiceApiException, CatalogApiException {
+    public void testInvoiceGenerationFailureScenario() throws InvoiceApiException, CatalogApiException {
         BillingEventSet events = new MockBillingEventSet();
         UUID subscriptionId = UUID.randomUUID();
         UUID accountId = UUID.randomUUID();
@@ -627,7 +632,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice1 = generator.generateInvoice(accountId, events, null, creationDate, Currency.USD);
         assertNotNull(invoice1);
         assertEquals(invoice1.getNumberOfItems(), 1);
-        assertEquals(invoice1.getTotalAmount().compareTo(ZERO), 0);
+        assertEquals(invoice1.getBalance().compareTo(ZERO), 0);
 
         List<Invoice> invoiceList = new ArrayList<Invoice>();
         invoiceList.add(invoice1);
@@ -636,7 +641,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         assertNotNull(invoice2);
         assertEquals(invoice2.getNumberOfItems(), 1);
         assertEquals(invoice2.getInvoiceItems().get(0).getStartDate().compareTo(trialPhaseEndDate), 0);
-        assertEquals(invoice2.getTotalAmount().compareTo(new BigDecimal("3.21")), 0);
+        assertEquals(invoice2.getBalance().compareTo(new BigDecimal("3.21")), 0);
 
         invoiceList.add(invoice2);
         DateTime targetDate = trialPhaseEndDate.toMutableDateTime().dayOfMonth().set(BILL_CYCLE_DAY).toDateTime();
@@ -644,7 +649,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         assertNotNull(invoice3);
         assertEquals(invoice3.getNumberOfItems(), 1);
         assertEquals(invoice3.getInvoiceItems().get(0).getStartDate().compareTo(targetDate), 0);
-        assertEquals(invoice3.getTotalAmount().compareTo(DISCOUNT_PRICE), 0);
+        assertEquals(invoice3.getBalance().compareTo(DISCOUNT_PRICE), 0);
 
         invoiceList.add(invoice3);
         targetDate = targetDate.plusMonths(6);
@@ -710,9 +715,10 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice = generator.generateInvoice(accountId, events, existingInvoices, targetDate, currency);
         assertNotNull(invoice);
         assertEquals(invoice.getNumberOfItems(), expectedNumberOfItems);
-
         existingInvoices.add(invoice);
-        assertEquals(invoice.getTotalAmount(), expectedAmount);
+
+        distributeItems(existingInvoices);
+        assertEquals(invoice.getBalance(), expectedAmount);
     }
 
     @Test
@@ -736,7 +742,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice invoice1 = generator.generateInvoice(accountId, events, null, april25, Currency.USD);
         assertNotNull(invoice1);
         assertEquals(invoice1.getNumberOfItems(), 1);
-        assertEquals(invoice1.getTotalAmount().compareTo(TEN), 0);
+        assertEquals(invoice1.getBalance().compareTo(TEN), 0);
 
         List<Invoice> invoices = new ArrayList<Invoice>();
         invoices.add(invoice1);
@@ -758,7 +764,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         invoices.add(invoice2);
         assertNotNull(invoice2);
         assertEquals(invoice2.getNumberOfItems(), 2);
-        assertEquals(invoice2.getTotalAmount().compareTo(TWENTY_FIVE.multiply(new BigDecimal("0.9")).setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD)), 0);
+        assertEquals(invoice2.getBalance().compareTo(TWENTY_FIVE.multiply(new BigDecimal("0.9")).setScale(NUMBER_OF_DECIMALS, ROUNDING_METHOD)), 0);
 
         // perform a repair (change base plan; remove one add-on)
         // event stream should include just two plans
@@ -775,10 +781,10 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         assertNotNull(invoice3);
         assertEquals(invoice3.getNumberOfItems(), 5);
         // -4.50 -18 - 10 (to correct the previous 2 invoices) + 4.50 + 13
-        assertEquals(invoice3.getTotalAmount().compareTo(FIFTEEN.negate()), 0);
+        assertEquals(invoice3.getBalance().compareTo(FIFTEEN.negate()), 0);
     }
 
-    @Test(enabled=false)
+    @Test
     public void testRepairForPaidInvoice() throws CatalogApiException, InvoiceApiException {
         // create an invoice
         DateTime april25 = new DateTime(2012, 4, 25, 0, 0, 0, 0);
@@ -795,6 +801,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         events.add(createBillingEvent(originalSubscription.getId(), april25, originalPlan, originalPlanEvergreen, 25));
 
         Invoice invoice1 = generator.generateInvoice(accountId, events, null, april25, Currency.USD);
+        assertEquals(invoice1.getNumberOfItems(), 1);
         List<Invoice> invoices = new ArrayList<Invoice>();
         invoices.add(invoice1);
 
@@ -812,34 +819,94 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         // generate a new invoice
         Invoice invoice2 = generator.generateInvoice(accountId, events, invoices, april25, Currency.USD);
+        assertEquals(invoice2.getNumberOfItems(), 4);
         invoices.add(invoice2);
 
         // move items to the correct invoice (normally, the dao calls will sort that out)
-        generator.distributeItems(invoices);
+        distributeItems(invoices);
 
         // ensure that the original invoice balance is zero
-
         assertEquals(invoice1.getBalance().compareTo(ZERO), 0);
 
         // ensure that the account balance is correct
-        assertEquals(invoice2.getBalance().compareTo(FIVE.negate()), 0);
+        assertEquals(invoice2.getBalance().compareTo(ZERO), 0);
 
+        // ensure that the account has a credit balance
+        BigDecimal creditBalance = invoice1.getAmountCredited().add(invoice2.getAmountCredited());
+        assertTrue(creditBalance.compareTo(FIVE) == 0);
     }
 
-    /*
-    test scenario: create invoice, pay invoice, change entitlement (repair)
+    private void distributeItems(List<Invoice> invoices) {
+        Map<UUID, Invoice> invoiceMap = new HashMap<UUID, Invoice>();
+
+        for (Invoice invoice : invoices) {
+            invoiceMap.put(invoice.getId(), invoice);
+        }
+
+        for (final Invoice invoice: invoices) {
+            Iterator<InvoiceItem> itemIterator = invoice.getInvoiceItems().iterator();
+            final UUID invoiceId = invoice.getId();
+
+            while (itemIterator.hasNext()) {
+                InvoiceItem item = itemIterator.next();
+
+                if (!item.getInvoiceId().equals(invoiceId)) {
+                    Invoice thisInvoice = invoiceMap.get(item.getInvoiceId());
+                    if (thisInvoice == null) {
+                        throw new NullPointerException();
+                    }
+                    thisInvoice.addInvoiceItem(item);
+                    itemIterator.remove();
+                }
+            }
+        }
+    }
+
+    @Test
+    public void testAutoInvoiceOff() throws CatalogApiException, InvoiceApiException {
+        Currency currency = Currency.USD;
+        List<Invoice> invoices = new ArrayList<Invoice>();
+        MockBillingEventSet eventSet = new MockBillingEventSet();
+        UUID accountId = UUID.randomUUID();
+
+        DateTime startDate = new DateTime(2012, 1, 1, 0, 12, 34, 0);
 
-    test scenario: two subscriptions, one with auto_invoice_off
+        // add first subscription creation event
+        UUID subscriptionId1 = UUID.randomUUID();
+        Plan plan1 = new MockPlan();
+        PlanPhase plan1phase1 = createMockMonthlyPlanPhase(FIFTEEN, null, PhaseType.DISCOUNT);
+        BillingEvent subscription1creation = createBillingEvent(subscriptionId1, startDate, plan1, plan1phase1, 1);
+        eventSet.add(subscription1creation);
 
-    test scenario: create invoice, pay invoice, change entitlement, generate invoices to use up credits
+        // add second subscription creation event
+        UUID subscriptionId2 = UUID.randomUUID();
+        Plan plan2 = new MockPlan();
+        PlanPhase plan2phase1 = createMockMonthlyPlanPhase(TWELVE, null, PhaseType.EVERGREEN);
+        eventSet.add(createBillingEvent(subscriptionId2, startDate, plan2, plan2phase1, 1));
 
-    test scenario: create invoice, pay invoice, add account-level credit, generate invoice
-     */
+        // generate the first invoice
+        Invoice invoice1 = generator.generateInvoice(accountId, eventSet, invoices, startDate, currency);
+        assertNotNull(invoice1);
+        assertTrue(invoice1.getBalance().compareTo(FIFTEEN.add(TWELVE)) == 0);
+        invoices.add(invoice1);
+
+        // set auto invoice off for first subscription (i.e. remove event from BillingEventSet and add subscription id to the list
+        // generate invoice
+        eventSet.remove(subscription1creation);
+        eventSet.addSubscriptionWithAutoInvoiceOff(subscriptionId1);
 
-    @Test(enabled=false)
-    public void testAutoInvoiceOff() {
-        //BillingEventSet eventSet = new MockBillingEventSet();
-        fail();
+        DateTime targetDate2 = startDate.plusMonths(1);
+        Invoice invoice2 = generator.generateInvoice(accountId, eventSet, invoices, targetDate2, currency);
+        assertNotNull(invoice2);
+        assertTrue(invoice2.getBalance().compareTo(TWELVE) == 0);
+        invoices.add(invoice2);
+
+        DateTime targetDate3 = targetDate2.plusMonths(1);
+        eventSet.clearSubscriptionsWithAutoInvoiceOff();
+        eventSet.add(subscription1creation);
+        Invoice invoice3 = generator.generateInvoice(accountId, eventSet, invoices, targetDate3, currency);
+        assertNotNull(invoice3);
+        assertTrue(invoice3.getBalance().compareTo(FIFTEEN.multiply(TWO).add(TWELVE)) == 0);
     }
 
     @Test
@@ -860,7 +927,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
         Invoice initialInvoice = generator.generateInvoice(accountId, billingEventSet, null, startDate, Currency.USD);
         assertNotNull(initialInvoice);
         assertEquals(initialInvoice.getNumberOfItems(), 1);
-        assertEquals(initialInvoice.getTotalAmount().compareTo(TEN), 0);
+        assertEquals(initialInvoice.getBalance().compareTo(TEN), 0);
         invoices.add(initialInvoice);
 
         // add account-level credit
@@ -872,7 +939,7 @@ public class DefaultInvoiceGeneratorTests extends InvoicingTestBase {
 
         // invoice one month after the initial subscription
         Invoice finalInvoice = generator.generateInvoice(accountId, billingEventSet, invoices, startDate.plusMonths(1), Currency.USD);
-        assertEquals(finalInvoice.getTotalAmount().compareTo(FIVE), 0);
+        assertEquals(finalInvoice.getBalance().compareTo(FIVE), 0);
         assertEquals(finalInvoice.getNumberOfItems(), 2);
     }
 }
\ No newline at end of file
diff --git a/invoice/src/test/java/com/ning/billing/invoice/tests/InvoicingTestBase.java b/invoice/src/test/java/com/ning/billing/invoice/tests/InvoicingTestBase.java
index 25be5e2..5beea5c 100644
--- a/invoice/src/test/java/com/ning/billing/invoice/tests/InvoicingTestBase.java
+++ b/invoice/src/test/java/com/ning/billing/invoice/tests/InvoicingTestBase.java
@@ -62,6 +62,7 @@ public abstract class InvoicingTestBase {
     protected static final BigDecimal TWENTY_FOUR = new BigDecimal("24.0").setScale(NUMBER_OF_DECIMALS);
     protected static final BigDecimal TWENTY_FIVE = new BigDecimal("25.0").setScale(NUMBER_OF_DECIMALS);
 
+    protected static final BigDecimal TWENTY_SEVEN = new BigDecimal("27.0").setScale(NUMBER_OF_DECIMALS);
     protected static final BigDecimal TWENTY_EIGHT = new BigDecimal("28.0").setScale(NUMBER_OF_DECIMALS);
     protected static final BigDecimal TWENTY_NINE = new BigDecimal("29.0").setScale(NUMBER_OF_DECIMALS);
     protected static final BigDecimal THIRTY = new BigDecimal("30.0").setScale(NUMBER_OF_DECIMALS);
diff --git a/jaxrs/src/main/java/com/ning/billing/jaxrs/json/AccountTimelineJson.java b/jaxrs/src/main/java/com/ning/billing/jaxrs/json/AccountTimelineJson.java
index c9f627a..204cf6a 100644
--- a/jaxrs/src/main/java/com/ning/billing/jaxrs/json/AccountTimelineJson.java
+++ b/jaxrs/src/main/java/com/ning/billing/jaxrs/json/AccountTimelineJson.java
@@ -96,7 +96,7 @@ public class AccountTimelineJson {
         }
         this.invoices = new LinkedList<InvoiceJsonWithBundleKeys>();
         for (Invoice cur : invoices) {
-            this.invoices.add(new InvoiceJsonWithBundleKeys(cur.getTotalAmount(), cur.getId().toString(), cur.getInvoiceDate(), cur.getTargetDate(),
+            this.invoices.add(new InvoiceJsonWithBundleKeys(cur.getAmountCharged(), cur.getAmountCredited(), cur.getId().toString(), cur.getInvoiceDate(), cur.getTargetDate(),
                     Integer.toString(cur.getInvoiceNumber()), cur.getBalance(),
                     getBundleExternalKey(cur, bundles)));
         }
diff --git a/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonSimple.java b/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonSimple.java
index e96179e..5680db1 100644
--- a/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonSimple.java
+++ b/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonSimple.java
@@ -26,44 +26,35 @@ import org.joda.time.DateTime;
 import com.ning.billing.invoice.api.Invoice;
 
 public class InvoiceJsonSimple {
-
-    @JsonView(BundleTimelineViews.Base.class)
     private final BigDecimal amount;
-    
-    @JsonView(BundleTimelineViews.Base.class)
+    private final BigDecimal credit;
     private final String invoiceId;
-    
-    @JsonView(BundleTimelineViews.Base.class)
     private final DateTime invoiceDate;
-
-    @JsonView(BundleTimelineViews.Base.class)
     private final DateTime targetDate;
-
-    @JsonView(BundleTimelineViews.Base.class)
     private final String invoiceNumber;
-    
-    @JsonView(BundleTimelineViews.Base.class)
     private final BigDecimal balance;
 
-    
     public InvoiceJsonSimple() {
-        this.amount = null;
+        this.amount = BigDecimal.ZERO;
+        this.credit = BigDecimal.ZERO;
         this.invoiceId = null;
         this.invoiceDate = null;
         this.targetDate = null;        
         this.invoiceNumber = null;
-        this.balance = null;
+        this.balance = BigDecimal.ZERO;
     }
     
     @JsonCreator
     public InvoiceJsonSimple(@JsonProperty("amount") BigDecimal amount,
-            @JsonProperty("invoiceId") String invoiceId,
-            @JsonProperty("invoiceDate") DateTime invoiceDate,
-            @JsonProperty("targetDate") DateTime targetDate,            
-            @JsonProperty("invoiceNumber") String invoiceNumber,
-            @JsonProperty("balance") BigDecimal balance) {
+                             @JsonProperty("credit") BigDecimal credit,
+                             @JsonProperty("invoiceId") String invoiceId,
+                             @JsonProperty("invoiceDate") DateTime invoiceDate,
+                             @JsonProperty("targetDate") DateTime targetDate,
+                             @JsonProperty("invoiceNumber") String invoiceNumber,
+                             @JsonProperty("balance") BigDecimal balance) {
         super();
         this.amount = amount;
+        this.credit = credit;
         this.invoiceId = invoiceId;
         this.invoiceDate = invoiceDate;
         this.targetDate = targetDate;
@@ -72,7 +63,8 @@ public class InvoiceJsonSimple {
     }
 
     public InvoiceJsonSimple(Invoice input) {
-        this.amount = input.getTotalAmount();
+        this.amount = input.getAmountCharged();
+        this.credit = input.getAmountCredited();
         this.invoiceId = input.getId().toString();
         this.invoiceDate = input.getInvoiceDate();
         this.targetDate = input.getTargetDate();
@@ -84,6 +76,10 @@ public class InvoiceJsonSimple {
         return amount;
     }
 
+    public BigDecimal getCredit() {
+        return credit;
+    }
+
     public String getInvoiceId() {
         return invoiceId;
     }
@@ -110,6 +106,7 @@ public class InvoiceJsonSimple {
         int result = 1;
         result = prime * result + ((amount == null) ? 0 : amount.hashCode());
         result = prime * result + ((balance == null) ? 0 : balance.hashCode());
+        result = prime * result + ((credit == null) ? 0 : credit.hashCode());
         result = prime * result
                 + ((invoiceDate == null) ? 0 : invoiceDate.hashCode());
         result = prime * result
@@ -133,26 +130,37 @@ public class InvoiceJsonSimple {
                 return false;
         } else if (!amount.equals(other.amount))
             return false;
+
         if (balance == null) {
             if (other.balance != null)
                 return false;
         } else if (!balance.equals(other.balance))
             return false;
+
+        if (credit == null) {
+            if (other.credit != null)
+                return false;
+        } else if (!credit.equals(other.credit))
+            return false;
+
         if (invoiceDate == null) {
             if (other.invoiceDate != null)
                 return false;
         } else if (!invoiceDate.equals(other.invoiceDate))
             return false;
+
         if (invoiceId == null) {
             if (other.invoiceId != null)
                 return false;
         } else if (!invoiceId.equals(other.invoiceId))
             return false;
+
         if (invoiceNumber == null) {
             if (other.invoiceNumber != null)
                 return false;
         } else if (!invoiceNumber.equals(other.invoiceNumber))
             return false;
+
         return true;
     }
 }
diff --git a/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonWithBundleKeys.java b/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonWithBundleKeys.java
index 98e2844..f1b0b4a 100644
--- a/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonWithBundleKeys.java
+++ b/jaxrs/src/main/java/com/ning/billing/jaxrs/json/InvoiceJsonWithBundleKeys.java
@@ -24,11 +24,8 @@ import com.ning.billing.invoice.api.Invoice;
  */
 
 public class InvoiceJsonWithBundleKeys extends InvoiceJsonSimple {
-    
-    
     private final String bundleKeys;
 
-
     public InvoiceJsonWithBundleKeys() {
         super();
         this.bundleKeys = null;
@@ -36,13 +33,14 @@ public class InvoiceJsonWithBundleKeys extends InvoiceJsonSimple {
     
     @JsonCreator
     public InvoiceJsonWithBundleKeys(@JsonProperty("amount") BigDecimal amount,
-            @JsonProperty("invoiceId") String invoiceId,
-            @JsonProperty("invoiceDate") DateTime invoiceDate,
-            @JsonProperty("targetDate") DateTime targetDate,            
-            @JsonProperty("invoiceNumber") String invoiceNumber,
-            @JsonProperty("balance") BigDecimal balance,
-            @JsonProperty("externalBundleKeys") String bundleKeys) {
-        super(amount, invoiceId, invoiceDate, targetDate, invoiceNumber, balance);
+                                     @JsonProperty("credit") BigDecimal credit,
+                                     @JsonProperty("invoiceId") String invoiceId,
+                                     @JsonProperty("invoiceDate") DateTime invoiceDate,
+                                     @JsonProperty("targetDate") DateTime targetDate,
+                                     @JsonProperty("invoiceNumber") String invoiceNumber,
+                                     @JsonProperty("balance") BigDecimal balance,
+                                     @JsonProperty("externalBundleKeys") String bundleKeys) {
+        super(amount, credit, invoiceId, invoiceDate, targetDate, invoiceNumber, balance);
         this.bundleKeys = bundleKeys;
     }
 
diff --git a/payment/src/test/java/com/ning/billing/payment/MockInvoice.java b/payment/src/test/java/com/ning/billing/payment/MockInvoice.java
index d195b59..802b49a 100644
--- a/payment/src/test/java/com/ning/billing/payment/MockInvoice.java
+++ b/payment/src/test/java/com/ning/billing/payment/MockInvoice.java
@@ -23,6 +23,7 @@ import java.util.UUID;
 
 import javax.annotation.Nullable;
 
+import com.ning.billing.invoice.api.InvoiceItemType;
 import org.joda.time.DateTime;
 
 import com.ning.billing.catalog.api.Currency;
@@ -178,23 +179,37 @@ public class MockInvoice extends EntityBase implements Invoice {
     }
 
     @Override
-    public BigDecimal getTotalAmount() {
+    public BigDecimal getAmountCharged() {
         BigDecimal result = BigDecimal.ZERO;
     
         for(InvoiceItem i : invoiceItems) {
-            result = result.add(i.getAmount());
+            if (!i.getInvoiceItemType().equals(InvoiceItemType.CREDIT)) {
+                result = result.add(i.getAmount());
+            }
+        }
+        return result;
+    }
+
+    @Override
+    public BigDecimal getAmountCredited() {
+        BigDecimal result = BigDecimal.ZERO;
+
+        for(InvoiceItem i : invoiceItems) {
+            if (i.getInvoiceItemType().equals(InvoiceItemType.CREDIT)) {
+                result = result.add(i.getAmount());
+            }
         }
         return result;
     }
 
     @Override
     public BigDecimal getBalance() {
-        return getTotalAmount().subtract(getAmountPaid());
+        return getAmountCharged().subtract(getAmountPaid().subtract(getAmountCredited()));
     }
 
     @Override
     public boolean isDueForPayment(final DateTime targetDate, final int numberOfDays) {
-        if (getTotalAmount().compareTo(BigDecimal.ZERO) == 0) {
+        if (getBalance().compareTo(BigDecimal.ZERO) == 0) {
             return false;
         }