001    /*****************************************************************************
002     * Copyright (C) PicoContainer Organization. All rights reserved.            *
003     * ------------------------------------------------------------------------- *
004     * The software in this package is published under the terms of the BSD      *
005     * style license a copy of which has been included with this distribution in *
006     * the LICENSE.txt file.                                                     *
007     *                                                                           *
008     * Original code by Paul Hammant                                             *
009     *****************************************************************************/
010    package org.picocontainer.alternatives;
011    
012    import java.io.Serializable;
013    import java.util.Collections;
014    import java.util.Collection;
015    import java.util.List;
016    import org.picocontainer.PicoContainer;
017    import org.picocontainer.PicoVisitor;
018    import org.picocontainer.ComponentAdapter;
019    
020    /**
021     * empty pico container serving as recoil damper in situations where you 
022     * do not like to check whether container reference suplpied to you 
023     * is null or not
024     * @author  Konstantin Pribluda 
025     * @since 1.1
026    */
027    public class EmptyPicoContainer implements PicoContainer, Serializable {
028        public Object getComponentInstance(Object componentKey) {
029            return null;
030        }
031       
032        public Object getComponentInstanceOfType(Class componentType) {
033            return null;
034        }
035        public List getComponentInstances() {
036            return Collections.EMPTY_LIST;
037        }
038        
039        public PicoContainer getParent() {
040            return null;
041        }
042        public ComponentAdapter getComponentAdapter(Object componentKey) {
043            return null;
044        }
045        
046        public ComponentAdapter getComponentAdapterOfType(Class componentType) {
047            return null;
048        }
049       
050        public Collection getComponentAdapters() {
051            return Collections.EMPTY_LIST;
052        }
053        
054        public List getComponentAdaptersOfType(Class componentType) {
055            return Collections.EMPTY_LIST;
056        }
057        
058        public void verify()  {}
059        
060        public void accept(PicoVisitor visitor) { }
061        
062        public List getComponentInstancesOfType(Class componentType) {
063            return Collections.EMPTY_LIST;
064        }
065    
066        public void start() {}
067        public void stop() {}
068        public void dispose() {}
069    }