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 *
009 *****************************************************************************/
010 package org.picocontainer.adapters;
011
012 import org.picocontainer.*;
013 import org.picocontainer.adapters.AbstractAdapter;
014 import org.picocontainer.lifecycle.NullLifecycleStrategy;
015 import org.picocontainer.monitors.NullComponentMonitor;
016
017 import java.lang.reflect.Type;
018
019 /**
020 * <p>
021 * Component adapter which wraps a component instance.
022 * </p>
023 * <p>
024 * This component adapter supports both a {@link Behavior Behavior} and a
025 * {@link org.picocontainer.LifecycleStrategy LifecycleStrategy} to control the lifecycle of the component.
026 * The lifecycle manager methods simply delegate to the lifecycle strategy methods
027 * on the component instance.
028 * </p>
029 *
030 * @author Aslak Hellesøy
031 * @author Paul Hammant
032 * @author Mauro Talevi
033 */
034 @SuppressWarnings("serial")
035 public final class InstanceAdapter<T> extends AbstractAdapter<T> implements ComponentLifecycle<T>, LifecycleStrategy {
036
037 /**
038 * The actual instance of the component.
039 */
040 private final T componentInstance;
041
042 /**
043 * Lifecycle Strategy for the component adpater.
044 */
045 private final LifecycleStrategy lifecycleStrategy;
046 private boolean started;
047
048
049 public InstanceAdapter(Object componentKey, T componentInstance, LifecycleStrategy lifecycleStrategy, ComponentMonitor componentMonitor) throws PicoCompositionException {
050 super(componentKey, getInstanceClass(componentInstance), componentMonitor);
051 this.componentInstance = componentInstance;
052 this.lifecycleStrategy = lifecycleStrategy;
053 }
054
055 public InstanceAdapter(Object componentKey, T componentInstance) {
056 this(componentKey, componentInstance, new NullLifecycleStrategy(), new NullComponentMonitor());
057 }
058
059 public InstanceAdapter(Object componentKey, T componentInstance, LifecycleStrategy lifecycleStrategy) {
060 this(componentKey, componentInstance, lifecycleStrategy, new NullComponentMonitor());
061 }
062
063 public InstanceAdapter(Object componentKey, T componentInstance, ComponentMonitor componentMonitor) {
064 this(componentKey, componentInstance, new NullLifecycleStrategy(), componentMonitor);
065 }
066
067 private static Class getInstanceClass(Object componentInstance) {
068 if (componentInstance == null) {
069 throw new NullPointerException("componentInstance cannot be null");
070 }
071 return componentInstance.getClass();
072 }
073
074 public T getComponentInstance(PicoContainer container, Type into) {
075 return componentInstance;
076 }
077
078 public void verify(PicoContainer container) {
079 }
080
081 public String getDescriptor() {
082 return "Instance-";
083 }
084
085 public void start(PicoContainer container) {
086 start(componentInstance);
087 }
088
089 public void stop(PicoContainer container) {
090 stop(componentInstance);
091 }
092
093 public void dispose(PicoContainer container) {
094 dispose(componentInstance);
095 }
096
097 public boolean componentHasLifecycle() {
098 return hasLifecycle(componentInstance.getClass());
099 }
100
101 public boolean isStarted() {
102 return started;
103 }
104
105 // ~~~~~~~~ LifecycleStrategy ~~~~~~~~
106
107 public void start(Object component) {
108 lifecycleStrategy.start(componentInstance);
109 started = true;
110 }
111
112 public void stop(Object component) {
113 lifecycleStrategy.stop(componentInstance);
114 started = false;
115 }
116
117 public void dispose(Object component) {
118 lifecycleStrategy.dispose(componentInstance);
119 }
120
121 public boolean hasLifecycle(Class<?> type) {
122 return lifecycleStrategy.hasLifecycle(type);
123 }
124
125 public boolean isLazy(ComponentAdapter<?> adapter) {
126 return lifecycleStrategy.isLazy(adapter);
127 }
128 }