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