| /* |
| * Copyright (c) 2010, Rickard Öberg. All Rights Reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| package org.qi4j.dci.moneytransfer.context; |
| |
| import org.qi4j.api.injection.scope.This; |
| import org.qi4j.api.mixin.Mixins; |
| import org.qi4j.dci.moneytransfer.domain.data.BalanceData; |
| |
| /** |
| * Context for transfer of money between two accounts. Roles are defined within the context, |
| * and only the role maps know about them outside of this context. |
| */ |
| public class TransferMoneyContext |
| { |
| // Object->Role mappings |
| public SourceAccountRole sourceAccount; |
| public DestinationAccountRole destinationAccount; |
| |
| // Context setup |
| // Objects are specified using their data interface, and then cast to the role interfaces |
| public TransferMoneyContext bind( BalanceData source, BalanceData destination ) |
| { |
| this.sourceAccount = (SourceAccountRole) source; |
| this.destinationAccount = (DestinationAccountRole) destination; |
| return this; |
| } |
| |
| // Interactions |
| public Integer availableFunds() |
| { |
| return sourceAccount.availableFunds(); |
| } |
| |
| public void transfer( int amount ) |
| throws IllegalArgumentException |
| { |
| sourceAccount.transfer( amount, destinationAccount ); |
| } |
| |
| // More interactions could go here... |
| |
| // Roles defined by this context, with default implementations |
| @Mixins( SourceAccountRole.Mixin.class ) |
| public interface SourceAccountRole |
| { |
| // Role Methods |
| public void transfer( int amount, DestinationAccountRole destinationAccount ) |
| throws IllegalArgumentException; |
| |
| Integer availableFunds(); |
| |
| // Default implementation |
| |
| class Mixin |
| implements SourceAccountRole |
| { |
| @This |
| BalanceData data; |
| |
| public Integer availableFunds() |
| { |
| // Could be balance, or balance - non-confirmed transfers, or somesuch |
| return data.getBalance(); |
| } |
| |
| public void transfer( int amount, DestinationAccountRole destinationAccount ) |
| throws IllegalArgumentException |
| { |
| // Validate command |
| if( !( data.getBalance() >= amount ) ) |
| { |
| throw new IllegalArgumentException( "Not enough available funds" ); |
| } |
| |
| // Command is ok - create events in the data |
| data.decreasedBalance( amount ); |
| |
| // Look up the destination account from the current transfer context |
| destinationAccount.deposit( amount ); |
| } |
| } |
| } |
| |
| @Mixins( DestinationAccountRole.Mixin.class ) |
| public interface DestinationAccountRole |
| { |
| public void deposit( int amount ); |
| |
| class Mixin |
| implements DestinationAccountRole |
| { |
| @This |
| BalanceData data; |
| |
| public void deposit( int amount ) |
| { |
| data.increasedBalance( amount ); |
| } |
| } |
| } |
| } |