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.Behavior;
013 import org.picocontainer.PicoContainer;
014 import org.picocontainer.LifecycleStrategy;
015 import org.picocontainer.ComponentMonitor;
016 import org.picocontainer.PicoCompositionException;
017 import org.picocontainer.ComponentLifecycle;
018 import org.picocontainer.adapters.AbstractAdapter;
019 import org.picocontainer.lifecycle.NullLifecycleStrategy;
020 import org.picocontainer.monitors.NullComponentMonitor;
021
022 import java.lang.reflect.Type;
023
024 /**
025 * <p>
026 * Component adapter which wraps a component instance.
027 * </p>
028 * <p>
029 * This component adapter supports both a {@link Behavior Behavior} and a
030 * {@link org.picocontainer.LifecycleStrategy LifecycleStrategy} to control the lifecycle of the component.
031 * The lifecycle manager methods simply delegate to the lifecycle strategy methods
032 * on the component instance.
033 * </p>
034 *
035 * @author Aslak Hellesøy
036 * @author Paul Hammant
037 * @author Mauro Talevi
038 */
039 @SuppressWarnings("serial")
040 public final class InstanceAdapter<T> extends AbstractAdapter<T> implements ComponentLifecycle<T>, LifecycleStrategy {
041
042 /**
043 * The actual instance of the component.
044 */
045 private final T componentInstance;
046
047 /**
048 * Lifecycle Strategy for the component adpater.
049 */
050 private final LifecycleStrategy lifecycleStrategy;
051 private boolean started;
052
053
054 public InstanceAdapter(Object componentKey, T componentInstance, LifecycleStrategy lifecycleStrategy, ComponentMonitor componentMonitor) throws PicoCompositionException {
055 super(componentKey, getInstanceClass(componentInstance), componentMonitor);
056 this.componentInstance = componentInstance;
057 this.lifecycleStrategy = lifecycleStrategy;
058 }
059
060 public InstanceAdapter(Object componentKey, T componentInstance) {
061 this(componentKey, componentInstance, new NullLifecycleStrategy(), new NullComponentMonitor());
062 }
063
064 public InstanceAdapter(Object componentKey, T componentInstance, LifecycleStrategy lifecycleStrategy) {
065 this(componentKey, componentInstance, lifecycleStrategy, new NullComponentMonitor());
066 }
067
068 public InstanceAdapter(Object componentKey, T componentInstance, ComponentMonitor componentMonitor) {
069 this(componentKey, componentInstance, new NullLifecycleStrategy(), componentMonitor);
070 }
071
072 private static Class getInstanceClass(Object componentInstance) {
073 if (componentInstance == null) {
074 throw new NullPointerException("componentInstance cannot be null");
075 }
076 return componentInstance.getClass();
077 }
078
079 public T getComponentInstance(PicoContainer container, Type into) {
080 return componentInstance;
081 }
082
083 public void verify(PicoContainer container) {
084 }
085
086 public String getDescriptor() {
087 return "Instance-";
088 }
089
090 public void start(PicoContainer container) {
091 start(componentInstance);
092 }
093
094 public void stop(PicoContainer container) {
095 stop(componentInstance);
096 }
097
098 public void dispose(PicoContainer container) {
099 dispose(componentInstance);
100 }
101
102 public boolean componentHasLifecycle() {
103 return hasLifecycle(componentInstance.getClass());
104 }
105
106 public boolean isStarted() {
107 return started;
108 }
109
110 // ~~~~~~~~ LifecycleStrategy ~~~~~~~~
111
112 public void start(Object component) {
113 lifecycleStrategy.start(componentInstance);
114 started = true;
115 }
116
117 public void stop(Object component) {
118 lifecycleStrategy.stop(componentInstance);
119 started = false;
120 }
121
122 public void dispose(Object component) {
123 lifecycleStrategy.dispose(componentInstance);
124 }
125
126 public boolean hasLifecycle(Class<?> type) {
127 return lifecycleStrategy.hasLifecycle(type);
128 }
129
130
131 }