# ValueBuilderInstance.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.value;

    import org.qi4j.api.association.AssociationStateHolder;
    import org.qi4j.api.common.ConstructionException;
    import org.qi4j.api.composite.Composite;
    import org.qi4j.api.value.NoSuchValueException;
    import org.qi4j.api.value.ValueBuilder;
    import org.qi4j.runtime.composite.StateResolver;
    import org.qi4j.spi.module.ModelModule;
    import org.qi4j.runtime.structure.ModuleInstance;

    import static org.qi4j.functional.Iterables.first;

    /**
     * Implementation of ValueBuilder
     */
    public final class ValueBuilderInstance<T>
        implements ValueBuilder<T>
    {

        private final ModuleInstance currentModule;
        private final ValueInstance prototypeInstance;

        public ValueBuilderInstance( ModelModule<ValueModel> compositeModelModule, ModuleInstance currentModule, StateResolver stateResolver )
        {
            ValueStateInstance state = new ValueStateInstance( compositeModelModule, currentModule, stateResolver );
            prototypeInstance = compositeModelModule.model().newValueInstance( compositeModelModule.module(), state );
            prototypeInstance.prepareToBuild();
            this.currentModule = currentModule;
        }

        @Override
        public T prototype()
        {
            return prototypeInstance.<T>proxy();
        }

        @Override
        public AssociationStateHolder state()
        {
            return prototypeInstance.state();
        }

        @Override
        public <K> K prototypeFor( Class<K> mixinType )
        {
            return prototypeInstance.newProxy( mixinType );
        }

        @Override
        @SuppressWarnings( "unchecked" )
        public T newInstance()
            throws ConstructionException
        {
            Class<Composite> valueType = (Class<Composite>) first( prototypeInstance.types() );

            ModelModule<ValueModel> valueModel = currentModule.typeLookup().lookupValueModel( valueType );

            if( valueModel == null )
            {
                throw new NoSuchValueException( valueType.getName(), currentModule.name() );
            }
            return new ValueBuilderWithPrototype<>( valueModel, currentModule, prototype() ).newInstance();
        }

    }