001    /**
002     Licensed to the Apache Software Foundation (ASF) under one or more
003     contributor license agreements.  See the NOTICE file distributed with
004     this work for additional information regarding copyright ownership.
005     The ASF licenses this file to You under the Apache License, Version 2.0
006     (the "License"); you may not use this file except in compliance with
007     the License.  You may obtain a copy of the License at
008    
009          http://www.apache.org/licenses/LICENSE-2.0
010    
011     Unless required by applicable law or agreed to in writing, software
012     distributed under the License is distributed on an "AS IS" BASIS,
013     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     See the License for the specific language governing permissions and
015     limitations under the License.
016    */
017    package org.apache.commons.inject.impl;
018    
019    import org.apache.commons.inject.api.IBinding;
020    import org.apache.commons.inject.api.IInjector;
021    import org.apache.commons.inject.api.IKey;
022    import org.apache.commons.inject.api.Key;
023    import org.apache.commons.inject.api.NoSuchBindingException;
024    
025    /**
026     * Abstract implementation of an {@link IInjector injector}.
027     */
028    public abstract class AbstractInjector implements IInjector {
029            protected abstract <T> IBinding<T> getBinding(IKey<T> pKey);
030            protected abstract <T> IBinding<T> requireBinding(IKey<T> pKey);
031    
032            @Override
033            public <T> T getInstance(Class<T> pType) {
034                    final IKey<T> key = new Key<T>(pType);
035                    return getInstance(key);
036            }
037    
038            @Override
039            public <T> T getInstance(Class<T> pType, String pName) {
040                    final IKey<T> key = new Key<T>(pType, pName);
041                    return getInstance(key);
042            }
043    
044            @Override
045            public <T> T getInstance(IKey<T> pKey) {
046                    final IBinding<T> binding = getBinding(pKey);
047                    if (binding == null) {
048                            return null;
049                    } else {
050                            return binding.getProvider().get();
051                    }
052            }
053    
054            @Override
055            public <T> T requireInstance(Class<T> pType) throws NoSuchBindingException {
056                    final IKey<T> key = new Key<T>(pType);
057                    return requireInstance(key);
058            }
059    
060            @Override
061            public <T> T requireInstance(Class<T> pType, String pName)
062                            throws NoSuchBindingException {
063                    final IKey<T> key = new Key<T>(pType, pName);
064                    return requireInstance(key);
065            }
066    
067            @Override
068            public <T> T requireInstance(IKey<T> pKey) throws NoSuchBindingException {
069                    final IBinding<T> binding = getBinding(pKey);
070                    if (binding == null) {
071                            throw new NoSuchBindingException("No binding registered for key: " + pKey);
072                    } else {
073                            return binding.getProvider().get();
074                    }
075            }
076    
077            @Override
078            public void injectMembers(Object pInstance) {
079                    if (pInstance == null) {
080                            throw new NullPointerException("The instance must not be null.");
081                    }
082                    @SuppressWarnings("unchecked")
083                    final Class<Object> cl = (Class<Object>) pInstance.getClass();
084                    final IKey<Object> key = new Key<Object>(cl);
085                    IBinding<Object> binding = requireBinding(key);
086                    binding.getPoint().injectTo(pInstance, this);
087            }
088    }