1 /* 2 * Copyright 2013 Google LLC 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 package com.google.auto.factory.processor; 17 18 import static com.google.auto.common.MoreElements.isAnnotationPresent; 19 import static com.google.common.base.Preconditions.checkArgument; 20 import static javax.tools.Diagnostic.Kind.ERROR; 21 22 import com.google.auto.factory.AutoFactory; 23 import com.google.auto.factory.Provided; 24 import javax.annotation.processing.Messager; 25 import javax.lang.model.element.Element; 26 import javax.lang.model.element.ExecutableElement; 27 import javax.lang.model.element.VariableElement; 28 import javax.lang.model.util.ElementKindVisitor6; 29 import org.checkerframework.checker.nullness.qual.Nullable; 30 31 final class ProvidedChecker { 32 private final Messager messager; 33 ProvidedChecker(Messager messager)34 ProvidedChecker(Messager messager) { 35 this.messager = messager; 36 } 37 checkProvidedParameter(Element element)38 void checkProvidedParameter(Element element) { 39 checkArgument( 40 isAnnotationPresent(element, Provided.class), "%s not annoated with @Provided", element); 41 element.accept( 42 new ElementKindVisitor6<@Nullable Void, @Nullable Void>() { 43 @Override 44 protected @Nullable Void defaultAction(Element e, @Nullable Void p) { 45 throw new AssertionError("Provided can only be applied to parameters"); 46 } 47 48 @Override 49 public @Nullable Void visitVariableAsParameter( 50 VariableElement providedParameter, @Nullable Void p) { 51 providedParameter 52 .getEnclosingElement() 53 .accept( 54 new ElementKindVisitor6<@Nullable Void, @Nullable Void>() { 55 @Override 56 protected @Nullable Void defaultAction(Element e, @Nullable Void p) { 57 raiseError( 58 providedParameter, "@%s may only be applied to constructor parameters"); 59 return null; 60 } 61 62 @Override 63 public @Nullable Void visitExecutableAsConstructor( 64 ExecutableElement constructor, @Nullable Void p) { 65 if (!(annotatedWithAutoFactory(constructor) 66 || annotatedWithAutoFactory(constructor.getEnclosingElement()))) { 67 raiseError( 68 providedParameter, 69 "@%s may only be applied to constructors requesting an auto-factory"); 70 } 71 return null; 72 } 73 }, 74 p); 75 return null; 76 } 77 }, 78 null); 79 } 80 raiseError(VariableElement providedParameter, String messageFormat)81 private void raiseError(VariableElement providedParameter, String messageFormat) { 82 messager.printMessage( 83 ERROR, 84 String.format(messageFormat, Provided.class.getSimpleName()), 85 providedParameter, 86 Mirrors.getAnnotationMirror(providedParameter, Provided.class).get()); 87 } 88 annotatedWithAutoFactory(Element e)89 private static boolean annotatedWithAutoFactory(Element e) { 90 return isAnnotationPresent(e, AutoFactory.class); 91 } 92 } 93