# LibraryMixin.java

    /*
     * Copyright 2009 Niclas Hedhman.
     *
     * 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.tutorials.services.step2;

    import org.qi4j.api.injection.scope.Structure;
    import org.qi4j.api.value.ValueBuilder;
    import org.qi4j.api.value.ValueBuilderFactory;

    public class LibraryMixin
        implements Library
    {
        @Structure
        ValueBuilderFactory factory;

        @Override
        public Book borrowBook( String author, String title )
        {
            ValueBuilder<Book> builder = factory.newValueBuilder( Book.class );
            Book prototype = builder.prototype();
            prototype.author().set( author );
            prototype.title().set( title );
            Book book = builder.newInstance();
            System.out.println( "Book borrowed: " + book.title().get() + " by " + book.author().get() );
            return book;
        }

        @Override
        public void returnBook( Book book )
        {
            System.out.println( "Book returned: " + book.title().get() + " by " + book.author().get() );
        }
    }