MentaContainer

package org.mentacontainer;

/**
 * A very simple container that provides:
 * <ul>
 *   <li> Bean instantiation (duh!)</li>
 *   <li> Constructor injection for bean setup</li>
 *   <li> Setter injection for bean setup</li>
 *   <li> Auto-wiring based on name and type</li>
 *   <li> Singleton</li>
 *   <li> Wiring of external beans with the beans configured in this container</li>
 *   <li> Annotation and XML free (programmatic configuration is the way to go!)
 * </ul>
 *
 * It does not get much simpler than that.
 *
 * @author sergio.oliveira.jr@gmail.com
 *
 */
public interface Container {
       
        /**
         * Get an instance from the container.
         *
         * The instance will be fully initialized (constructor and/or setters) and fully wired.
         *
         * @param key The key representing the bean to return. The name of the bean in the container.
         * @return The fully initialized and wired bean.
         */
        public <T> T get(String key);
       
        /**
         * Configure a bean to be returned with the given implementation when {@link #get(String)} is called.
         *
         * @param key The key representing the bean to return. The name of the bean in the container.
         * @param klass The class used to instantiate the bean, in other words, its implementation.
         * @param singleton A boolean to indicate if this bean will be a singleton.
         * @return The component created. (Fluent API)
         */
        public Component ioc(String key, Class<? extends Object> klass, boolean singleton);
       
        /**
         * Same as {@link #ioc(String, Class, boolean)} except that it assumes
         * singleton is false.
         *
         * @param key
         * @param klass
         * @return The component created. (Fluent API)
         */
        public Component ioc(String key, Class<?extends Object> klass);
       
        /**
         * Set up IoC based on the component passed.
         *
         * @param key The key representing the bean to return. The name of the bean in the container.
         * @param component The component for the IoC.
         * @return The component passed as a parameter. (Fluent API)
         * @see Component
         */
        public Component ioc(String key, Component component);
       
        /**
         * Configure a bean dependency to be auto-wired by the container. In general you want the
         * type of the dependency to be an interface, for loosely couple dependencies. It works like that:<br/><br/>
         *
         * Whenever the container returns a bean, it checks to see if it has a property named <i>property</i>
         * and if the type of the property is <i>klass</i>. If it does, then it looks for a bean named
         * <i>source</i> and injects it inside the first bean it is returning. This approach is recursive
         * so all properties are checked up the class hierarchy, until it reaches Object.
         *
         * @param property a bean property that will require another bean, in other words, the required
         *                                 bean will be injected in the property of the bean been requested from the container. (auto-wiring by name)
         * @param klass the type of the dependency, in other words, the type of the auto-wiring. (auto-wiring by type)
         * @param source The dependency itself, coming from the container as well, in other words, the bean that will be injected in the original bean
         * @return The container itself. (Fluent API)
         */
        public Dependency autowire(String property, Class<? extends Object> klass, String source);
       
        /**
         * Same as {@link #autowire(String, Class, String)} except that it assumes that the property name will be the source name, in other words,
         * the property name is the same as the bean name that will be injected as the dependency.
         *
         * @param property
         * @param klass
         * @return The container itself. (Fluent API)
         */
        public Dependency autowire(String property, Class<? extends Object> klass);
       
        /**
         * Setup a dependency.
         *
         * @param dependency The dependency to setup
         * @return The dependency itself. (Fluent API)
         * @see Dependency
         */
        public Dependency autowire(Dependency dependency);
       
        /**
         * Take a given bean and populate its properties with other beans coming from this container. Perhaps you can call this auto-wiring.
         * You basically checking properties of the given bean and looking for values (by name and type!) inside the container. And injecting
         * in the given bean, in other words, populating it.
         *
         * @param bean The bean to be populated with other beans from the container.
         * @return The container itself. (Fluent API)
         */
        public Container populate(Object bean);
       
        /**
         * Check whether the container is configured to provide a bean with name 'key'.
         *
         * @param key The key representing the bean inside the container.
         * @return true if the container contains this bean.
         */
        public boolean contains(String key);
}