# RuntimeFactory.java

    /*
     * Licensed to the Apache Software Foundation (ASF) under one
     * or more contributor license agreements.  See the NOTICE file
     * distributed with this work for additional information
     * regarding copyright ownership.  The ASF licenses this file
     * to you 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.bootstrap;

    /**
     * Zest runtime factory.
     */
    public interface RuntimeFactory
    {
        Qi4jRuntime createRuntime();

        /**
         * Standalone application Zest runtime factory.
         */
        public final class StandaloneApplicationRuntimeFactory
            implements RuntimeFactory
        {
            @Override
            public Qi4jRuntime createRuntime()
            {
                ClassLoader loader = getClass().getClassLoader();
                try
                {
                    Class<? extends Qi4jRuntime> runtimeClass = loadRuntimeClass( loader );
                    return runtimeClass.newInstance();
                }
                catch( ClassNotFoundException e )
                {
                    System.err.println( "Zest Runtime jar is not present in the classpath." );
                }
                catch( InstantiationException | IllegalAccessException e )
                {
                    System.err.println( "Invalid Zest Runtime class. If you are providing your own Zest Runtime, please " +
                                        "contact qi4j-dev at Google Groups for assistance." );
                }
                return null;
            }

            @SuppressWarnings( { "unchecked" } )
            private Class<? extends Qi4jRuntime> loadRuntimeClass( ClassLoader loader )
                throws ClassNotFoundException
            {
                return (Class<? extends Qi4jRuntime>) loader.loadClass( "org.qi4j.runtime.Qi4jRuntimeImpl" );
            }
        }
    }