core/runtime/src/main/java/org/qi4j/runtime/activation/ActivatorModel.java

/*
 * Copyright (c) 2014, Paul Merlin. All Rights Reserved.
 *
 * Licensed  under the  Apache License,  Version 2.0  (the "License");
 * you may not use  this file  except in  compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed  under the  License is distributed on an "AS IS" BASIS,
 * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
 * implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.qi4j.runtime.activation;

import org.qi4j.api.activation.Activator;
import org.qi4j.api.activation.ActivatorDescriptor;
import org.qi4j.api.common.ConstructionException;
import org.qi4j.functional.HierarchicalVisitor;
import org.qi4j.functional.VisitableHierarchy;
import org.qi4j.runtime.composite.ConstructorsModel;
import org.qi4j.runtime.injection.InjectedFieldsModel;
import org.qi4j.runtime.injection.InjectedMethodsModel;
import org.qi4j.runtime.injection.InjectionContext;

/**
 * Model for a single Activator.
 *
 * @param <ActivateeType> Type of the activation target
 */
public class ActivatorModel<ActivateeType>
    implements ActivatorDescriptor, VisitableHierarchy<Object, Object>
{
    private final Class<? extends Activator<ActivateeType>> activatorType;
    private final ConstructorsModel constructorsModel;
    private final InjectedFieldsModel injectedFieldsModel;
    private final InjectedMethodsModel injectedMethodsModel;

    public ActivatorModel( Class<? extends Activator<ActivateeType>> activatorType )
    {
        this.activatorType = activatorType;
        this.constructorsModel = new ConstructorsModel( activatorType );
        this.injectedFieldsModel = new InjectedFieldsModel( activatorType );
        this.injectedMethodsModel = new InjectedMethodsModel( activatorType );
    }

    @Override
    public <ThrowableType extends Throwable> boolean accept( HierarchicalVisitor<? super Object, ? super Object, ThrowableType> visitor )
        throws ThrowableType
    {
        if( visitor.visitEnter( this ) )
        {
            if( constructorsModel.accept( visitor ) )
            {
                if( injectedFieldsModel.accept( visitor ) )
                {
                    injectedMethodsModel.accept( visitor );
                }
            }
        }
        return visitor.visitLeave( this );
    }

    public Activator<ActivateeType> newInstance()
    {
        try
        {
            return activatorType.newInstance();
        }
        catch( InstantiationException | IllegalAccessException ex )
        {
            throw new ConstructionException( "Could not instantiate " + activatorType.getName(), ex );
        }
    }

    @SuppressWarnings( "unchecked" )
    public Activator<ActivateeType> newInstance( InjectionContext injectionContext )
    {
        try
        {
            Activator<ActivateeType> instance = (Activator<ActivateeType>) constructorsModel.newInstance( injectionContext );
            injectionContext = new InjectionContext( injectionContext.module(), injectionContext.uses(), instance );
            inject( injectionContext, instance );
            return instance;
        }
        catch( Exception ex )
        {
            throw new ConstructionException( "Could not instantiate " + activatorType.getName(), ex );
        }
    }

    public void inject( InjectionContext injectionContext, Activator<ActivateeType> instance )
    {
        injectedFieldsModel.inject( injectionContext, instance );
        injectedMethodsModel.inject( injectionContext, instance );
    }

    @Override
    public String toString()
    {
        return activatorType.getName();
    }

}