1 /** 2 * Copyright (C) 2008 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.internal; 18 19 import com.google.inject.spi.Dependency; 20 21 /** 22 * Resolves a single parameter, to be used in a constructor or method invocation. 23 */ 24 final class SingleParameterInjector<T> { 25 private static final Object[] NO_ARGUMENTS = {}; 26 27 private final Dependency<T> dependency; 28 private final BindingImpl<? extends T> binding; 29 30 SingleParameterInjector(Dependency<T> dependency, BindingImpl<? extends T> binding) { 31 this.dependency = dependency; 32 this.binding = binding; 33 } 34 35 private T inject(Errors errors, InternalContext context) throws ErrorsException { 36 Dependency previous = context.pushDependency(dependency, binding.getSource()); 37 try { 38 return binding.getInternalFactory().get(errors.withSource(dependency), context, dependency, false); 39 } finally { 40 context.popStateAndSetDependency(previous); 41 } 42 } 43 44 /** 45 * Returns an array of parameter values. 46 */ 47 static Object[] getAll(Errors errors, InternalContext context, 48 SingleParameterInjector<?>[] parameterInjectors) throws ErrorsException { 49 if (parameterInjectors == null) { 50 return NO_ARGUMENTS; 51 } 52 53 int numErrorsBefore = errors.size(); 54 55 int size = parameterInjectors.length; 56 Object[] parameters = new Object[size]; 57 58 // optimization: use manual for/each to save allocating an iterator here 59 for (int i = 0; i < size; i++) { 60 SingleParameterInjector<?> parameterInjector = parameterInjectors[i]; 61 try { 62 parameters[i] = parameterInjector.inject(errors, context); 63 } catch (ErrorsException e) { 64 errors.merge(e.getErrors()); 65 } 66 } 67 68 errors.throwIfNewErrors(numErrorsBefore); 69 return parameters; 70 } 71 } 72
