| 1 | /** |
| 2 | * Licensed to jclouds, Inc. (jclouds) under one or more |
| 3 | * contributor license agreements. See the NOTICE file |
| 4 | * distributed with this work for additional information |
| 5 | * regarding copyright ownership. jclouds licenses this file |
| 6 | * to you under the Apache License, Version 2.0 (the |
| 7 | * "License"); you may not use this file except in compliance |
| 8 | * with the License. You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, |
| 13 | * software distributed under the License is distributed on an |
| 14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | * KIND, either express or implied. See the License for the |
| 16 | * specific language governing permissions and limitations |
| 17 | * under the License. |
| 18 | */ |
| 19 | package org.jclouds.logging.config; |
| 20 | |
| 21 | import static com.google.common.collect.Sets.filter; |
| 22 | |
| 23 | import java.lang.annotation.Annotation; |
| 24 | import java.lang.reflect.Field; |
| 25 | import java.util.Arrays; |
| 26 | import java.util.HashSet; |
| 27 | import java.util.Set; |
| 28 | |
| 29 | import javax.annotation.Resource; |
| 30 | import javax.inject.Inject; |
| 31 | import javax.inject.Named; |
| 32 | |
| 33 | import org.jclouds.logging.Logger; |
| 34 | import org.jclouds.logging.Logger.LoggerFactory; |
| 35 | |
| 36 | import com.google.common.annotations.VisibleForTesting; |
| 37 | import com.google.common.base.Predicate; |
| 38 | import com.google.inject.ProvisionException; |
| 39 | import com.google.inject.TypeLiteral; |
| 40 | import com.google.inject.spi.InjectionListener; |
| 41 | import com.google.inject.spi.TypeEncounter; |
| 42 | import com.google.inject.spi.TypeListener; |
| 43 | |
| 44 | /** |
| 45 | * TypeListener that will bind {@link org.jclouds.logging.Logger} to members annotated with |
| 46 | * {@link javax.annotation.Resource} |
| 47 | * <p/> |
| 48 | * This class is a TypeListener so that it can create a logger whose category is |
| 49 | * the same as the name of the injected instance's class. |
| 50 | * <p/> |
| 51 | * Note that this occurs post-object construction through |
| 52 | * {@link com.google.inject.Binder#bindListener}. |
| 53 | * <p/> |
| 54 | * Here's an example usage: |
| 55 | * <pre> |
| 56 | * class A { |
| 57 | * @Resource private Logger logger = Logger.NULL; |
| 58 | * } |
| 59 | * <p/> |
| 60 | * Injector i = Guice.createInjector(new AbstractModule() { |
| 61 | * @Override protected void configure() { |
| 62 | * bindListener(any(), new |
| 63 | * BindLoggersAnnotatedWithResource( new |
| 64 | * JDKLogger.JDKLoggerFactory())); |
| 65 | * } |
| 66 | * }); |
| 67 | * <p/> |
| 68 | * A = i.getInstance(A.class); |
| 69 | * // A will now have a logger associated with it |
| 70 | * </pre> |
| 71 | * |
| 72 | * @author Adrian Cole |
| 73 | */ |
| 74 | public class BindLoggersAnnotatedWithResource implements TypeListener { |
| 75 | |
| 76 | static class AssignLoggerToField<I> implements InjectionListener<I> { |
| 77 | private final Logger logger; |
| 78 | private final Field field; |
| 79 | |
| 80 | AssignLoggerToField(Logger logger, Field field) { |
| 81 | this.logger = logger; |
| 82 | this.field = field; |
| 83 | } |
| 84 | |
| 85 | public void afterInjection(I injectee) { |
| 86 | try { |
| 87 | field.setAccessible(true); |
| 88 | field.set(injectee, logger); |
| 89 | } catch (IllegalAccessException e) { |
| 90 | throw new ProvisionException(e.getMessage(), e); |
| 91 | } |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | static class LoggerFieldsAnnotatedWithResource implements |
| 96 | Predicate<Field> { |
| 97 | public boolean apply(Field from) { |
| 98 | Annotation inject = from.getAnnotation(Resource.class); |
| 99 | return (inject != null && from.getType().isAssignableFrom(Logger.class)); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | private final LoggerFactory loggerFactory; |
| 104 | |
| 105 | @Inject |
| 106 | public BindLoggersAnnotatedWithResource(LoggerFactory loggerFactory) { |
| 107 | this.loggerFactory = loggerFactory; |
| 108 | } |
| 109 | |
| 110 | public <I> void hear(TypeLiteral<I> injectableType, |
| 111 | TypeEncounter<I> encounter) { |
| 112 | |
| 113 | Class<? super I> type = injectableType.getRawType(); |
| 114 | Set<Field> loggerFields = getLoggerFieldsAnnotatedWithResource(type); |
| 115 | if (loggerFields.size() == 0) |
| 116 | return; |
| 117 | |
| 118 | Logger logger = loggerFactory.getLogger(type.getName()); |
| 119 | |
| 120 | for (Field field : loggerFields) { |
| 121 | if (field.isAnnotationPresent(Named.class)){ |
| 122 | Named name = field.getAnnotation(Named.class); |
| 123 | encounter.register(new AssignLoggerToField<I>(loggerFactory.getLogger(name.value()), field)); |
| 124 | } else { |
| 125 | encounter.register(new AssignLoggerToField<I>(logger, field)); |
| 126 | } |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | @VisibleForTesting |
| 131 | Set<Field> getLoggerFieldsAnnotatedWithResource(Class<?> declaredType) { |
| 132 | Set<Field> fields = new HashSet<Field>(); |
| 133 | Class<?> type = declaredType; |
| 134 | while (type != null) { |
| 135 | fields.addAll(Arrays.asList(type.getDeclaredFields())); |
| 136 | type = type.getSuperclass(); |
| 137 | } |
| 138 | return filter(fields, new LoggerFieldsAnnotatedWithResource()); |
| 139 | } |
| 140 | } |