org.picocontainer.adapters.AbstractAdapter Maven / Gradle / Ivy
/*****************************************************************************
* Copyright (C) PicoContainer Organization. All rights reserved. *
* ------------------------------------------------------------------------- *
* The software in this package is published under the terms of the BSD *
* style license a copy of which has been included with this distribution in *
* the LICENSE.txt file. *
* *
* Original code by *
*****************************************************************************/
package org.picocontainer.adapters;
import org.picocontainer.ComponentMonitor;
import org.picocontainer.PicoVisitor;
import org.picocontainer.ComponentAdapter;
import org.picocontainer.ComponentMonitorStrategy;
import org.picocontainer.PicoContainer;
import org.picocontainer.PicoCompositionException;
import org.picocontainer.injectors.ProviderAdapter;
import org.picocontainer.injectors.Provider;
import org.picocontainer.monitors.AbstractComponentMonitor;
import org.picocontainer.monitors.NullComponentMonitor;
import java.io.Serializable;
/**
* Base class for a ComponentAdapter with general functionality.
* This implementation provides basic checks for a healthy implementation of a ComponentAdapter.
* It does not allow to use null
for the component key or the implementation,
* ensures that the implementation is a concrete class and that the key is assignable from the
* implementation if the key represents a type.
*
* @author Paul Hammant
* @author Aslak Hellesøy
* @author Jon Tirsén
*/
public abstract class AbstractAdapter implements ComponentAdapter, ComponentMonitorStrategy, Serializable {
private Object componentKey;
private Class componentImplementation;
private ComponentMonitor componentMonitor;
/**
* Constructs a new ComponentAdapter for the given key and implementation.
* @param componentKey the search key for this implementation
* @param componentImplementation the concrete implementation
*/
public AbstractAdapter(Object componentKey, Class componentImplementation) {
this(componentKey, componentImplementation, new AbstractComponentMonitor());
this.componentMonitor = new NullComponentMonitor();
}
/**
* Constructs a new ComponentAdapter for the given key and implementation.
* @param componentKey the search key for this implementation
* @param componentImplementation the concrete implementation
* @param monitor the component monitor used by this ComponentAdapter
*/
public AbstractAdapter(Object componentKey, Class componentImplementation, ComponentMonitor monitor) {
if (monitor == null) {
throw new NullPointerException("ComponentMonitor==null");
}
this.componentMonitor = monitor;
if (componentImplementation == null) {
throw new NullPointerException("componentImplementation");
}
this.componentKey = componentKey;
this.componentImplementation = componentImplementation;
checkTypeCompatibility();
}
/**
* {@inheritDoc}
* @see org.picocontainer.ComponentAdapter#getComponentKey()
*/
public Object getComponentKey() {
if (componentKey == null) {
throw new NullPointerException("componentKey");
}
return componentKey;
}
/**
* {@inheritDoc}
* @see org.picocontainer.ComponentAdapter#getComponentImplementation()
*/
public Class extends T> getComponentImplementation() {
return componentImplementation;
}
protected void checkTypeCompatibility() {
if (componentKey instanceof Class) {
Class> componentType = (Class) componentKey;
if (Provider.class.isAssignableFrom(componentImplementation)) {
if (!componentType.isAssignableFrom(ProviderAdapter.getProvideMethod(componentImplementation).getReturnType())) {
throw newCCE(componentType);
}
} else {
if (!componentType.isAssignableFrom(componentImplementation)) {
throw newCCE(componentType);
}
}
}
}
private ClassCastException newCCE(Class> componentType) {
return new ClassCastException(componentImplementation.getName() + " is not a " + componentType.getName());
}
public T getComponentInstance(PicoContainer container) throws PicoCompositionException {
return getComponentInstance(container, null);
}
/**
* @return Returns the ComponentAdapter's class name and the component's key.
* @see java.lang.Object#toString()
*/
public String toString() {
return getDescriptor() + getComponentKey();
}
public void accept(PicoVisitor visitor) {
visitor.visitComponentAdapter(this);
}
public void changeMonitor(ComponentMonitor monitor) {
this.componentMonitor = monitor;
}
/**
* Returns the monitor currently used
* @return The ComponentMonitor currently used
*/
public ComponentMonitor currentMonitor(){
return componentMonitor;
}
public final ComponentAdapter getDelegate() {
return null;
}
public final U findAdapterOfType(Class adapterType) {
if (adapterType.isAssignableFrom(this.getClass())) {
return (U) this;
} else if (getDelegate() != null) {
return getDelegate().findAdapterOfType(adapterType);
}
return null;
}
}