1 /* 2 * Copyright (C) 2012 Google Inc. 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 com.google.inject.throwingproviders; 18 19 import com.google.inject.Binder; 20 import com.google.inject.TypeLiteral; 21 import com.google.inject.internal.Annotations; 22 import com.google.inject.internal.Errors; 23 import com.google.inject.spi.Message; 24 import java.lang.annotation.Annotation; 25 import java.lang.reflect.AnnotatedElement; 26 import java.lang.reflect.Constructor; 27 28 /** 29 * Utilities for the throwing provider module. 30 * 31 * @author sameb@google.com (Sam Berlin) 32 */ 33 class CheckedProvideUtils { 34 CheckedProvideUtils()35 private CheckedProvideUtils() {} 36 37 private static final String CONSTRUCTOR_RULES = 38 "Classes must have either one (and only one) constructor annotated with @ThrowingInject."; 39 40 @SuppressWarnings("unchecked") // safe because it's a constructor of the typeLiteral findThrowingConstructor( TypeLiteral<? extends T> typeLiteral, Binder binder)41 static <T> Constructor<? extends T> findThrowingConstructor( 42 TypeLiteral<? extends T> typeLiteral, Binder binder) { 43 44 Class<?> rawType = typeLiteral.getRawType(); 45 Errors errors = new Errors(rawType); 46 Constructor<?> cxtor = null; 47 for (Constructor<?> constructor : rawType.getDeclaredConstructors()) { 48 if (constructor.isAnnotationPresent(ThrowingInject.class)) { 49 if (cxtor != null) { 50 errors.addMessage( 51 "%s has more than one constructor annotated with @ThrowingInject. " 52 + CONSTRUCTOR_RULES, 53 rawType); 54 } 55 56 cxtor = constructor; 57 Annotation misplacedBindingAnnotation = 58 Annotations.findBindingAnnotation( 59 errors, cxtor, ((AnnotatedElement) cxtor).getAnnotations()); 60 if (misplacedBindingAnnotation != null) { 61 errors.misplacedBindingAnnotation(cxtor, misplacedBindingAnnotation); 62 } 63 } 64 } 65 66 if (cxtor == null) { 67 errors.addMessage( 68 "Could not find a suitable constructor in %s. " + CONSTRUCTOR_RULES, rawType); 69 } 70 71 for (Message msg : errors.getMessages()) { 72 binder.addError(msg); 73 } 74 return (Constructor<? extends T>) cxtor; 75 } 76 77 /** Adds errors to the binder if the exceptions aren't valid. */ validateExceptions( Binder binder, Iterable<TypeLiteral<?>> actualExceptionTypes, Iterable<Class<? extends Throwable>> expectedExceptionTypes, Class<? extends CheckedProvider> checkedProvider)78 static void validateExceptions( 79 Binder binder, 80 Iterable<TypeLiteral<?>> actualExceptionTypes, 81 Iterable<Class<? extends Throwable>> expectedExceptionTypes, 82 Class<? extends CheckedProvider> checkedProvider) { 83 // Validate the exceptions in the method match the exceptions 84 // in the CheckedProvider. 85 for (TypeLiteral<?> exType : actualExceptionTypes) { 86 Class<?> exActual = exType.getRawType(); 87 // Ignore runtime exceptions & errors. 88 if (RuntimeException.class.isAssignableFrom(exActual) 89 || Error.class.isAssignableFrom(exActual)) { 90 continue; 91 } 92 93 boolean notAssignable = true; 94 for (Class<? extends Throwable> exExpected : expectedExceptionTypes) { 95 if (exExpected.isAssignableFrom(exActual)) { 96 notAssignable = false; 97 break; 98 } 99 } 100 if (notAssignable) { 101 binder.addError( 102 "%s is not compatible with the exceptions (%s) declared in " 103 + "the CheckedProvider interface (%s)", 104 exActual, expectedExceptionTypes, checkedProvider); 105 } 106 } 107 } 108 } 109