/**
* Copyright (C) 2008 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.internal;
import com.google.inject.spi.Dependency;
/**
* Resolves a single parameter, to be used in a constructor or method invocation.
*/
final class SingleParameterInjector<T> {
private static final Object[] NO_ARGUMENTS = {};
private final Dependency<T> dependency;
private final InternalFactory<? extends T> factory;
SingleParameterInjector(Dependency<T> dependency, InternalFactory<? extends T> factory) {
this.dependency = dependency;
this.factory = factory;
}
private T inject(Errors errors, InternalContext context) throws ErrorsException {
Dependency previous = context.setDependency(dependency);
try {
return factory.get(errors.withSource(dependency), context, dependency);
} finally {
context.setDependency(previous);
}
}
/**
* Returns an array of parameter values.
*/
static Object[] getAll(Errors errors, InternalContext context,
SingleParameterInjector<?>[] parameterInjectors) throws ErrorsException {
if (parameterInjectors == null) {
return NO_ARGUMENTS;
}
int numErrorsBefore = errors.size();
int size = parameterInjectors.length;
Object[] parameters = new Object[size];
// optimization: use manual for/each to save allocating an iterator here
for (int i = 0; i < size; i++) {
SingleParameterInjector<?> parameterInjector = parameterInjectors[i];
try {
parameters[i] = parameterInjector.inject(errors, context);
} catch (ErrorsException e) {
errors.merge(e.getErrors());
}
}
errors.throwIfNewErrors(numErrorsBefore);
return parameters;
}
}