/**

  Licensed to the Apache Software Foundation (ASF) under one or more

  contributor license agreements.  See the NOTICE file distributed with

  this work for additional information regarding copyright ownership.

  The ASF licenses this file to You 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 org.apache.commons.inject.impl;

 import org.apache.commons.inject.api.IBinding;

 import org.apache.commons.inject.api.IInjector;

 import org.apache.commons.inject.api.IKey;

 import org.apache.commons.inject.api.Key;

 import org.apache.commons.inject.api.NoSuchBindingException;

 /**

  * Abstract implementation of an {@link IInjector injector}.

  */

 public abstract class AbstractInjector implements IInjector {

         protected abstract <T> IBinding<T> getBinding(IKey<T> pKey);

         protected abstract <T> IBinding<T> requireBinding(IKey<T> pKey);

         @Override

         public <T> T getInstance(Class<T> pType) {

                 final IKey<T> key = new Key<T>(pType);

                 return getInstance(key);

         }

         @Override

         public <T> T getInstance(Class<T> pType, String pName) {

                 final IKey<T> key = new Key<T>(pType, pName);

                 return getInstance(key);

         }

         @Override

         public <T> T getInstance(IKey<T> pKey) {

                 final IBinding<T> binding = getBinding(pKey);

                 if (binding == null) {

                         return null;

                 } else {

                         return binding.getProvider().get();

                 }

         }

         @Override

         public <T> T requireInstance(Class<T> pType) throws NoSuchBindingException {

                 final IKey<T> key = new Key<T>(pType);

                 return requireInstance(key);

         }

         @Override

         public <T> T requireInstance(Class<T> pType, String pName)

                         throws NoSuchBindingException {

                 final IKey<T> key = new Key<T>(pType, pName);

                 return requireInstance(key);

         }

         @Override

         public <T> T requireInstance(IKey<T> pKey) throws NoSuchBindingException {

                 final IBinding<T> binding = getBinding(pKey);

                 if (binding == null) {

                         throw new NoSuchBindingException("No binding registered for key: " + pKey);

                 } else {

                         return binding.getProvider().get();

                 }

         }

         @Override

         public void injectMembers(Object pInstance) {

                 if (pInstance == null) {

                         throw new NullPointerException("The instance must not be null.");

                 }

                 @SuppressWarnings("unchecked")

                 final Class<Object> cl = (Class<Object>) pInstance.getClass();

                 final IKey<Object> key = new Key<Object>(cl);

                 IBinding<Object> binding = requireBinding(key);

                 binding.getPoint().injectTo(pInstance, this);

         }

 }