# CompositeModel.java

    /*
     * Copyright (c) 2008, Rickard Öberg. 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.composite;

    import java.lang.reflect.Constructor;
    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.util.LinkedHashSet;
    import java.util.Set;
    import org.qi4j.api.common.ConstructionException;
    import org.qi4j.api.common.MetaInfo;
    import org.qi4j.api.common.Visibility;
    import org.qi4j.api.composite.Composite;
    import org.qi4j.api.composite.CompositeDescriptor;
    import org.qi4j.api.composite.InvalidCompositeException;
    import org.qi4j.api.structure.Module;
    import org.qi4j.functional.HierarchicalVisitor;
    import org.qi4j.functional.Iterables;
    import org.qi4j.functional.VisitableHierarchy;
    import org.qi4j.runtime.injection.Dependencies;
    import org.qi4j.runtime.injection.DependencyModel;
    import org.qi4j.runtime.structure.ModuleInstance;
    import org.qi4j.spi.module.ModuleSpi;

    import static java.lang.reflect.Proxy.newProxyInstance;
    import static org.qi4j.functional.Iterables.first;
    import static org.qi4j.functional.Iterables.toList;

    /**
     * JAVADOC
     */
    public abstract class CompositeModel
        implements VisitableHierarchy<Object, Object>, Dependencies, CompositeDescriptor
    {
        protected final MixinsModel mixinsModel;
        protected final CompositeMethodsModel compositeMethodsModel;
        private final Set<Class<?>> types;
        private final Visibility visibility;
        private final MetaInfo metaInfo;
        protected final StateModel stateModel;
        protected Class<? extends Composite> proxyClass;
        protected Constructor<? extends Composite> proxyConstructor;

        protected CompositeModel( final Iterable<Class<?>> types,
                                  final Visibility visibility,
                                  final MetaInfo metaInfo,
                                  final MixinsModel mixinsModel,
                                  final StateModel stateModel,
                                  final CompositeMethodsModel compositeMethodsModel
        )
        {
            this.types = Iterables.addAll( new LinkedHashSet<Class<?>>(), types );
            this.visibility = visibility;
            this.metaInfo = metaInfo;
            this.stateModel = stateModel;
            this.compositeMethodsModel = compositeMethodsModel;
            this.mixinsModel = mixinsModel;

            // Create proxy class
            createProxyClass();
        }

        // Model
        @Override
        public Iterable<Class<?>> types()
        {
            return types;
        }

        public StateModel state()
        {
            return stateModel;
        }

        @Override
        public <T> T metaInfo( Class<T> infoType )
        {
            return metaInfo.get( infoType );
        }

        @Override
        public Visibility visibility()
        {
            return visibility;
        }

        @Override
        public boolean isAssignableTo( Class<?> type )
        {
            for( Class<?> aClass : types )
            {
                if( type.isAssignableFrom( aClass ) )
                {
                    return true;
                }
            }
            return false;
        }

        public MixinsModel mixinsModel()
        {
            return mixinsModel;
        }

        @Override
        @SuppressWarnings( { "raw", "unchecked" } )
        public Class<?> primaryType()
        {
            Class primaryType = null;
            for( Class type : mixinTypes() )
            {
                if( type.getName().equals( "scala.ScalaObject" ) )
                {
                    continue;
                }
                if( primaryType == null )
                {
                    primaryType = type;
                }
                else if( primaryType.isAssignableFrom( type ) )
                {
                    primaryType = type;
                }
            }
            return primaryType;
        }

        @Override
        public Iterable<Class<?>> mixinTypes()
        {
            return mixinsModel.mixinTypes();
        }

        @Override
        public Iterable<DependencyModel> dependencies()
        {
            return Iterables.flatten( mixinsModel.dependencies(), compositeMethodsModel.dependencies() );
        }

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

        @SuppressWarnings( { "raw", "unchecked" } )
        private void createProxyClass()
        {
            Class<?> mainType = first( types );
            if( mainType.isInterface() )
            {
                ClassLoader proxyClassloader = mainType.getClassLoader();

                Class<?>[] interfaces = Iterables.toArray( Class.class, Iterables.<Class>cast( types ) );
                proxyClass = (Class<? extends Composite>) ProxyGenerator.createProxyClass( proxyClassloader, interfaces );

                try
                {
                    proxyConstructor = proxyClass.getConstructor( InvocationHandler.class );
                }
                catch( NoSuchMethodException e )
                {
                    throw (InvalidCompositeException) new InvalidCompositeException( "Could not get proxy constructor" ).initCause( e );
                }
                proxyConstructor.setAccessible( true );
            }
            else
            {
                try
                {
                    proxyClass = new TransientClassLoader( getClass().getClassLoader() ).loadFragmentClass( mainType );
                    proxyConstructor = (Constructor<? extends Composite>) proxyClass.getConstructors()[ 0 ];
                }
                catch( ClassNotFoundException e )
                {
                    throw (InvalidCompositeException) new InvalidCompositeException( "Could not get proxy constructor" ).initCause( e );
                }
            }
        }

        // Context
        public final Object invoke( MixinsInstance mixins,
                                    Object proxy,
                                    Method method,
                                    Object[] args,
                                    ModuleSpi moduleInstance
        )
            throws Throwable
        {
            return compositeMethodsModel.invoke( mixins, proxy, method, args, moduleInstance );
        }

        public Composite newProxy( InvocationHandler invocationHandler )
            throws ConstructionException
        {
            Class<?> mainType = first( types() );
            if( mainType.isInterface() )
            {

                try
                {
                    return Composite.class.cast( proxyConstructor.newInstance( invocationHandler ) );
                }
                catch( Exception e )
                {
                    throw new ConstructionException( e );
                }
            }
            else
            {
                try
                {
                    Object[] args = new Object[ proxyConstructor.getParameterTypes().length ];
                    Composite composite = Composite.class.cast( proxyConstructor.newInstance( args ) );
                    proxyClass.getField( "_instance" ).set( composite, invocationHandler );
                    return composite;
                }
                catch( Exception e )
                {
                    throw new ConstructionException( e );
                }
            }
        }

        @SuppressWarnings( "raw" )
        public <T> T newProxy( InvocationHandler invocationHandler, Class<T> mixinType )
            throws IllegalArgumentException
        {

    //        if (!matchesAny( isAssignableFrom( mixinType ), types ))
            if( !mixinsModel.isImplemented( mixinType ) )
            {
                String message = "Composite " + primaryType().getName() + " does not implement type " + mixinType.getName();
                throw new IllegalArgumentException( message );
            }

            // Instantiate proxy for given mixin interface
            return mixinType.cast( newProxyInstance( mixinType.getClassLoader(), new Class[]{ mixinType }, invocationHandler ) );
        }

        @Override
        public String toString()
        {
            return toList( types ).toString();
        }
    }