PicoContainer example source code file (AbstractAdapter.java)

This example PicoContainer source code file (AbstractAdapter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - PicoContainer tags/keywords

abstractadapter, abstractadapter, abstractcomponentmonitor, class, class, componentmonitor, componentmonitor, componentmonitor==null, componentmonitorstrategy, io, nullpointerexception, nullpointerexception, object, serializable, string

The PicoContainer AbstractAdapter.java source code

/*****************************************************************************
 * 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.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 <code>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
 * @version $Revision: 3619 $
 */
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
     */
    protected AbstractAdapter(Object componentKey, Class componentImplementation) {
        this(componentKey, componentImplementation, new AbstractComponentMonitor());
        this.componentMonitor = NullComponentMonitor.getInstance();
    }

    /**
     * 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
     */
    protected 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 getComponentImplementation() {
        return componentImplementation;
    }

    protected void checkTypeCompatibility() {
        if (componentKey instanceof Class) {
            Class componentType = (Class) componentKey;
            if (!componentType.isAssignableFrom(componentImplementation)) {
                throw new ClassCastException(componentImplementation.getName() + " is not a " + componentType.getName());
            }
        }
    }

    /**
     * @return Returns the ComponentAdapter's class name and the component's key.
     * @see java.lang.Object#toString()
     */
    public String toString() {
        return getClass().getName() + "[" + 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;
    }


}