/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.xml.impl;

import java.util.Map;

import org.picocontainer.ComponentAdapter;
import org.picocontainer.MutablePicoContainer;
import org.picocontainer.defaults.ConstructorInjectionComponentAdapter;
import org.picocontainer.defaults.DefaultPicoContainer;
import org.picocontainer.defaults.DuplicateComponentKeyRegistrationException;
import org.picocontainer.defaults.InstanceComponentAdapter;

import javax.xml.namespace.QName;
import org.geotools.xml.Binding;


public class BindingLoader {
    
    Map bindings;
    
    public BindingLoader( Map bindings ) {
        this.bindings = bindings;
    }

    /**
     * Loads a binding with a specifc QName into a context.
     *
     * @param qName The qualified name of the type of the binding object.
     * @param context The context which is to contain the binding.
     *
     * @return The binding object of the associated type, otherwise null if
     * no such binding could be created.
     *
     */
    public Binding loadBinding(QName qName, MutablePicoContainer context) {
        Object o = bindings.get( qName );
        if ( o == null ) {
            return null;
        }
        if ( o instanceof ComponentAdapter ) {
            return (Binding) ((ComponentAdapter)o).getComponentInstance( context );
        }
        
        if ( o instanceof Class ) {
            return loadBinding(qName, (Class)o, context);
        }
        
        return (Binding) o;
    }

    /**
     * Loads a binding with a specifc class into a context.
     *
     * @param bindingClass The class of the binding.
     * @param context The context which is to contain the binding.
     *
     * @return The binding object of the associated type, otherwise null if
     * no such binding could be created.
     *
     */
    public Binding loadBinding(QName qName, Class bindingClass, MutablePicoContainer context) {
        //instantiate within the given context
        ComponentAdapter adapter = 
            new ConstructorInjectionComponentAdapter( qName, bindingClass );
        return (Binding) adapter.getComponentInstance( context );
    }

    /**
     * Returns the component adapter for a binding with the specified name.
     *
     * @param type The qualified name of the type of the binding.
     *
     * @return The binding class, or null if no such class exists.
     */
    protected ComponentAdapter getBinding(QName type) {
        Object o = bindings.get( type );
        if ( o == null ) {
            return null;
        }
        
        if ( o instanceof ComponentAdapter ) {
            return (ComponentAdapter) o; 
        }
        
        if ( o instanceof Class ) {
            return new ConstructorInjectionComponentAdapter( null, (Class) o ); 
        }
        
        return new InstanceComponentAdapter( null, o );
    }
}