| /** |
| * Copyright (C) 2007 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.inject.assistedinject; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| |
| import com.google.inject.ConfigurationException; |
| import com.google.inject.Injector; |
| import com.google.inject.Key; |
| import com.google.inject.Provider; |
| import com.google.inject.internal.Annotations; |
| |
| import java.lang.annotation.Annotation; |
| import java.lang.reflect.ParameterizedType; |
| import java.lang.reflect.Type; |
| |
| /** |
| * Models a method or constructor parameter. |
| * |
| * @author jmourits@google.com (Jerome Mourits) |
| * @author jessewilson@google.com (Jesse Wilson) |
| */ |
| class Parameter { |
| |
| private final Type type; |
| private final boolean isAssisted; |
| private final Annotation bindingAnnotation; |
| private final boolean isProvider; |
| |
| private volatile Provider<? extends Object> provider; |
| |
| public Parameter(Type type, Annotation[] annotations) { |
| this.type = type; |
| this.bindingAnnotation = getBindingAnnotation(annotations); |
| this.isAssisted = hasAssistedAnnotation(annotations); |
| this.isProvider = isProvider(type); |
| } |
| |
| public boolean isProvidedByFactory() { |
| return isAssisted; |
| } |
| |
| public Type getType() { |
| return type; |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder result = new StringBuilder(); |
| if (isAssisted) { |
| result.append("@Assisted "); |
| } |
| if (bindingAnnotation != null) { |
| result.append(bindingAnnotation).append(" "); |
| } |
| return result.append(type).toString(); |
| } |
| |
| private boolean hasAssistedAnnotation(Annotation[] annotations) { |
| for (Annotation annotation : annotations) { |
| if (annotation.annotationType().equals(Assisted.class)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Returns the Guice {@link Key} for this parameter. |
| */ |
| public Object getValue(Injector injector) { |
| if (null == provider) { |
| synchronized (this) { |
| if (null == provider) { |
| provider = isProvider |
| ? injector.getProvider(getBindingForType(getProvidedType(type))) |
| : injector.getProvider(getPrimaryBindingKey()); |
| } |
| } |
| } |
| |
| return isProvider ? provider : provider.get(); |
| } |
| |
| public boolean isBound(Injector injector) { |
| return isBound(injector, getPrimaryBindingKey()) |
| || isBound(injector, fixAnnotations(getPrimaryBindingKey())); |
| } |
| |
| private boolean isBound(Injector injector, Key<?> key) { |
| // This method is particularly lame - we really need an API that can test |
| // for any binding, implicit or explicit |
| try { |
| return injector.getBinding(key) != null; |
| } catch (ConfigurationException e) { |
| return false; |
| } |
| } |
| |
| /** |
| * Replace annotation instances with annotation types, this is only |
| * appropriate for testing if a key is bound and not for injecting. |
| * |
| * See Guice bug 125, |
| * http://code.google.com/p/google-guice/issues/detail?id=125 |
| */ |
| public Key<?> fixAnnotations(Key<?> key) { |
| return key.getAnnotation() == null |
| ? key |
| : Key.get(key.getTypeLiteral(), key.getAnnotation().annotationType()); |
| } |
| |
| Key<?> getPrimaryBindingKey() { |
| return isProvider |
| ? getBindingForType(getProvidedType(type)) |
| : getBindingForType(type); |
| } |
| |
| private Type getProvidedType(Type type) { |
| return ((ParameterizedType) type).getActualTypeArguments()[0]; |
| } |
| |
| private boolean isProvider(Type type) { |
| return type instanceof ParameterizedType |
| && ((ParameterizedType) type).getRawType() == Provider.class; |
| } |
| |
| private Key<?> getBindingForType(Type type) { |
| return bindingAnnotation != null |
| ? Key.get(type, bindingAnnotation) |
| : Key.get(type); |
| } |
| |
| /** |
| * Returns the unique binding annotation from the specified list, or |
| * {@code null} if there are none. |
| * |
| * @throws IllegalStateException if multiple binding annotations exist. |
| */ |
| private Annotation getBindingAnnotation(Annotation[] annotations) { |
| Annotation bindingAnnotation = null; |
| for (Annotation annotation : annotations) { |
| if (Annotations.isBindingAnnotation(annotation.annotationType())) { |
| checkArgument(bindingAnnotation == null, |
| "Parameter has multiple binding annotations: %s and %s", bindingAnnotation, annotation); |
| bindingAnnotation = annotation; |
| } |
| } |
| return bindingAnnotation; |
| } |
| } |