PicoContainer example source code file (ComponentAdapter.java)

This example PicoContainer source code file (ComponentAdapter.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

class, class, componentadapter, object, object, picocompositionexception, picocompositionexception, t, t

The PicoContainer ComponentAdapter.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.                                                     *
 *****************************************************************************/
package org.picocontainer;

import org.picocontainer.behaviors.CachingBehavior;

/**
 * A component adapter is responsible for providing a specific component instance. An instance of an implementation of
 * this interface is used inside a {@link PicoContainer} for every registered component or instance.  Each
 * <code>ComponentAdapter instance has to have a key which is unique within that container. The key itself is
 * either a class type (normally an interface) or an identifier.
 *
 * @author Jon Tirsén
 * @author Paul Hammant
 * @author Aslak Hellesøy
 * @version $Revision: 3602 $
 * @see MutablePicoContainer an extension of the PicoContainer interface which allows you to modify the contents of the
 *      container.
 */
public interface ComponentAdapter<T> {
    /**
     * Retrieve the key associated with the component.
     *
     * @return the component's key. Should either be a class type (normally an interface) or an identifier that is
     *         unique (within the scope of the current PicoContainer).
     */
    Object getComponentKey();

    /**
     * Retrieve the class of the component.
     *
     * @return the component's implementation class. Should normally be a concrete class (ie, a class that can be
     *         instantiated).
     */
    Class<T> getComponentImplementation();

    /**
     * Retrieve the component instance. This method will usually create a new instance each time it is called, but that
     * is not required. For example, {@link CachingBehavior} will always return the
     * same instance.
     *
     * @param container the {@link PicoContainer}, that is used to resolve any possible dependencies of the instance.
     * @return the component instance.
     * @throws PicoCompositionException if the component could not be instantiated.
     * @throws PicoCompositionException  if the component has dependencies which could not be resolved, or
     *                                     instantiation of the component lead to an ambigous situation within the
     *                                     container.
     */
    T getComponentInstance(PicoContainer container) throws PicoCompositionException;

    /**
     * Verify that all dependencies for this adapter can be satisifed. Normally, the adapter should verify this by
     * checking that the associated PicoContainer contains all the needed dependnecies.
     *
     * @param container the {@link PicoContainer}, that is used to resolve any possible dependencies of the instance.
     * @throws PicoCompositionException if one or more dependencies cannot be resolved.
     */
    void verify(PicoContainer container) throws PicoCompositionException;

    /**
     * Accepts a visitor for this ComponentAdapter. The method is normally called by visiting a {@link PicoContainer}, that
     * cascades the visitor also down to all its ComponentAdapter instances.
     *
     * @param visitor the visitor.
     */
    void accept(PicoVisitor visitor);
}