1 /* 2 * Copyright (C) 2019 The Dagger Authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package dagger.example.atm; 18 19 import java.math.BigDecimal; 20 21 /** 22 * Abstract {@link Command} that expects a single argument that can be converted to {@link 23 * BigDecimal}. 24 */ 25 abstract class BigDecimalCommand extends SingleArgCommand { 26 27 private final Outputter outputter; 28 BigDecimalCommand(Outputter outputter)29 protected BigDecimalCommand(Outputter outputter) { 30 this.outputter = outputter; 31 } 32 33 @Override handleArg(String arg)34 protected final Result handleArg(String arg) { 35 BigDecimal amount = tryParse(arg); 36 if (amount == null) { 37 outputter.output(arg + " is not a valid number"); 38 } else if (amount.signum() <= 0) { 39 outputter.output("amount must be positive"); 40 } else { 41 handleAmount(amount); 42 } 43 return Result.handled(); 44 } 45 tryParse(String arg)46 private static BigDecimal tryParse(String arg) { 47 try { 48 return new BigDecimal(arg); 49 } catch (NumberFormatException e) { 50 return null; 51 } 52 } 53 54 /** Handles the given (positive) {@code amount} of money. */ handleAmount(BigDecimal amount)55 protected abstract void handleAmount(BigDecimal amount); 56 } 57