Replaced multiple IFs in the AccountAppraisalDelegate by implementing…

… State pattern to represent the AccountSide of the Account implementation
ghacupha · Apr 11, 2018 · 6023932 · 6023932
1 parent 5ecf210
commit 6023932
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Showing 7 changed files with 162 additions and 18 deletions.
diff --git a/src/main/java/io/github/ghacupha/keeper/book/api/Account.java b/src/main/java/io/github/ghacupha/keeper/book/api/Account.java
@@ -19,6 +19,7 @@
 import io.github.ghacupha.keeper.book.balance.AccountBalance;
 import io.github.ghacupha.keeper.book.balance.AccountSide;
 import io.github.ghacupha.keeper.book.base.AccountAppraisalDelegate;
+import io.github.ghacupha.keeper.book.base.AccountDetails;
 import io.github.ghacupha.keeper.book.unit.time.TimePoint;
 import io.github.ghacupha.keeper.book.util.MismatchedCurrencyException;
 import io.github.ghacupha.keeper.book.util.UntimelyBookingDateException;
@@ -90,4 +91,8 @@ public interface Account {
      * @return Returns this object's current copy of the {@link Entry} items
      */
     List<Entry> getEntries();
+
+    AccountDetails getAccountDetails();
+
+    void setAccountSide(AccountSide accountSide);
 }
diff --git a/src/main/java/io/github/ghacupha/keeper/book/base/AccountAppraisalDelegate.java b/src/main/java/io/github/ghacupha/keeper/book/base/AccountAppraisalDelegate.java
@@ -20,6 +20,9 @@
 import io.github.ghacupha.keeper.book.api.Entry;
 import io.github.ghacupha.keeper.book.balance.AccountBalance;
 import io.github.ghacupha.keeper.book.balance.AccountSide;
+import io.github.ghacupha.keeper.book.base.state.AccountCreditState;
+import io.github.ghacupha.keeper.book.base.state.AccountDebitState;
+import io.github.ghacupha.keeper.book.base.state.AccountState;
 import io.github.ghacupha.keeper.book.unit.money.Cash;
 import io.github.ghacupha.keeper.book.unit.money.HardCash;
 import io.github.ghacupha.keeper.book.unit.time.DateRange;
@@ -42,9 +45,18 @@ public class AccountAppraisalDelegate {
 
     private final Account account;
 
+    private AccountState accountSideState;
+
+    private final AccountState debitAccountState;
+    private final AccountState creditAccountState;
+
     AccountAppraisalDelegate(Account account) {
 
         this.account = account;
+        debitAccountState = new AccountDebitState(this.account);
+        creditAccountState = new AccountCreditState(this.account);
+
+        this.accountSideState = account.getAccountSide() == DEBIT ? debitAccountState : creditAccountState;
     }
 
     public AccountBalance balance(DateRange dateRange){
@@ -59,24 +71,9 @@ public AccountBalance balance(DateRange dateRange){
             } else if(debits.isZero() && !credits.isZero()){
                 return new AccountBalance(credits, CREDIT);
             }
-        } else if (account.getAccountSide() == DEBIT) {
-
-            if (credits.isMoreThan(debits)) {
-                return new AccountBalance(credits.minus(debits).abs(), CREDIT);
-            }
+        } else {
 
-            if (!credits.isMoreThan(debits)) {
-                return new AccountBalance(credits.minus(debits).abs(), DEBIT);
-            }
-        } else if (account.getAccountSide() == CREDIT) {
-
-            if (debits.isMoreThan(credits)) {
-                return new AccountBalance(debits.minus(credits).abs(), DEBIT);
-            }
-
-            if (!debits.isMoreThan(credits)) {
-                return new AccountBalance(debits.minus(credits).abs(), CREDIT);
-            }
+           return accountSideState.getAccountBalance(debits,credits);
         }
 
         return new AccountBalance(HardCash.of(0.0,account.getCurrency()),account.getAccountSide());

diff --git a/src/main/java/io/github/ghacupha/keeper/book/base/AssignableCollectionAccount.java b/src/main/java/io/github/ghacupha/keeper/book/base/AssignableCollectionAccount.java
@@ -118,4 +118,15 @@ public AccountSide getAccountSide() {
     public List<Entry> getEntries() {
         return null;
     }
+
+    @Override
+    public AccountDetails getAccountDetails() {
+        return accountDetails;
+    }
+
+    @Override
+    public void setAccountSide(final AccountSide accountSide) {
+
+        this.accountSide = accountSide;
+    }
 }
diff --git a/src/main/java/io/github/ghacupha/keeper/book/base/SimpleAccount.java b/src/main/java/io/github/ghacupha/keeper/book/base/SimpleAccount.java
@@ -20,6 +20,7 @@
 import io.github.ghacupha.keeper.book.api.Entry;
 import io.github.ghacupha.keeper.book.balance.AccountBalance;
 import io.github.ghacupha.keeper.book.balance.AccountSide;
+import io.github.ghacupha.keeper.book.base.state.AccountState;
 import io.github.ghacupha.keeper.book.unit.time.DateRange;
 import io.github.ghacupha.keeper.book.unit.time.SimpleDate;
 import io.github.ghacupha.keeper.book.unit.time.TimePoint;
@@ -63,6 +64,8 @@ public final class SimpleAccount implements Account {
     private final AccountDetails accountDetails;
     private volatile AccountSide accountSide;
 
+    private AccountState accountState;
+
     private volatile List<Entry> entries = new CopyOnWriteArrayList<>();
 
     /**
@@ -83,7 +86,7 @@ public final class SimpleAccount implements Account {
         this.entries = entries;
     }
 
-    SimpleAccount(final AccountSide accountSide, Currency currency, AccountDetails accountDetails) {
+    public SimpleAccount(final AccountSide accountSide, Currency currency, AccountDetails accountDetails) {
         this.currency = currency;
         this.accountSide = accountSide;
         this.accountDetails = accountDetails;
@@ -197,4 +200,16 @@ public AccountSide getAccountSide() {
         // The original accountSide remains. No side effects
         return this.accountSide == DEBIT ? DEBIT : CREDIT;
     }
+
+    @Override
+    public AccountDetails getAccountDetails() {
+
+        return accountDetails;
+    }
+
+    @Override
+    public void setAccountSide(final AccountSide accountSide) {
+
+        this.accountSide = accountSide;
+    }
 }
diff --git a/src/main/java/io/github/ghacupha/keeper/book/base/state/AccountCreditState.java b/src/main/java/io/github/ghacupha/keeper/book/base/state/AccountCreditState.java
@@ -0,0 +1,45 @@
+package io.github.ghacupha.keeper.book.base.state;
+
+import io.github.ghacupha.keeper.book.api.Account;
+import io.github.ghacupha.keeper.book.balance.AccountBalance;
+import io.github.ghacupha.keeper.book.balance.AccountSide;
+import io.github.ghacupha.keeper.book.unit.money.Cash;
+
+import static io.github.ghacupha.keeper.book.balance.AccountSide.DEBIT;
+
+public class AccountCreditState implements AccountState {
+
+    private Account account;
+    public AccountCreditState(Account account) {
+        this.account = account;
+    }
+
+    /**
+     * Get AccountBalance given the sum of debits and sum of credits
+     *
+     * @param debits
+     * @param credits
+     * @return
+     */
+    @Override
+    public AccountBalance getAccountBalance(final Cash debits,final Cash credits) {
+
+        if(credits.isMoreThan(debits)){
+            return new AccountBalance(credits.minus(debits).abs(),account.getAccountSide());
+        }
+
+        // The journal side of the account changes to DEBIT
+        account.setAccountSide(DEBIT);
+
+        return new AccountBalance(credits.minus(debits).abs(),DEBIT);
+    }
+
+    /**
+     * @return {@code AccountSide} of the Account
+     */
+    @Override
+    public AccountSide getAccountSide() {
+
+        return account.getAccountSide();
+    }
+}
diff --git a/src/main/java/io/github/ghacupha/keeper/book/base/state/AccountDebitState.java b/src/main/java/io/github/ghacupha/keeper/book/base/state/AccountDebitState.java
@@ -0,0 +1,46 @@
+package io.github.ghacupha.keeper.book.base.state;
+
+import io.github.ghacupha.keeper.book.api.Account;
+import io.github.ghacupha.keeper.book.balance.AccountBalance;
+import io.github.ghacupha.keeper.book.balance.AccountSide;
+import io.github.ghacupha.keeper.book.base.SimpleAccount;
+import io.github.ghacupha.keeper.book.base.state.AccountState;
+import io.github.ghacupha.keeper.book.unit.money.Cash;
+
+import static io.github.ghacupha.keeper.book.balance.AccountSide.CREDIT;
+
+public class AccountDebitState implements AccountState {
+
+    private Account account;
+
+    public AccountDebitState(Account account) {
+        this.account = account;
+    }
+
+    @Override
+    public AccountBalance getAccountBalance(Cash debits, Cash credits) {
+
+        if(debits.isMoreThan(credits)){
+            return new AccountBalance(debits.minus(credits).abs(),account.getAccountSide());
+        }
+
+        account.setAccountSide(CREDIT);
+
+        return new AccountBalance(credits.minus(debits).abs(),CREDIT);
+    }
+
+    @Override
+    public AccountSide getAccountSide() {
+        return account.getAccountSide();
+    }
+
+    @Override
+    public String toString() {
+
+        return "Debit state";
+    }
+
+    public Account getAccount() {
+        return account;
+    }
+}
diff --git a/src/main/java/io/github/ghacupha/keeper/book/base/state/AccountState.java b/src/main/java/io/github/ghacupha/keeper/book/base/state/AccountState.java
@@ -0,0 +1,25 @@
+package io.github.ghacupha.keeper.book.base.state;
+
+import io.github.ghacupha.keeper.book.balance.AccountBalance;
+import io.github.ghacupha.keeper.book.balance.AccountSide;
+import io.github.ghacupha.keeper.book.unit.money.Cash;
+
+/**
+ * Experimental representation of the states of the account
+ */
+public interface AccountState {
+
+    /**
+     * Get AccountBalance given the sum of debits and sum of credits
+     * @param debits
+     * @param credits
+     * @return
+     */
+    AccountBalance getAccountBalance(Cash debits,Cash credits);
+
+    /**
+     *
+     * @return {@code AccountSide} of the Account
+     */
+    AccountSide getAccountSide();
+}