# QueryBuilderFactoryImpl.java

    /*
     * Copyright 2007-2009 Niclas Hedhman.
     * Copyright 2008 Alin Dreghiciu.
     *
     * 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.query;

    import org.qi4j.api.query.NotQueryableException;
    import org.qi4j.api.query.QueryBuilder;
    import org.qi4j.api.query.QueryBuilderFactory;
    import org.qi4j.api.service.NoSuchServiceException;
    import org.qi4j.api.service.ServiceFinder;
    import org.qi4j.api.service.ServiceReference;
    import org.qi4j.api.util.NullArgumentException;
    import org.qi4j.spi.query.EntityFinder;

    /**
     * Default implementation of {@link QueryBuilderFactory}
     */
    public final class QueryBuilderFactoryImpl
        implements QueryBuilderFactory
    {
        private ServiceFinder finder;

        /**
         * Constructor.
         *
         * @param finder The ServiceFinder of the Module this QueryBuilderFactory belongs to.
         */
        public QueryBuilderFactoryImpl( ServiceFinder finder )
        {
            NullArgumentException.validateNotNull( "ServiceFinder", finder );
            this.finder = finder;
        }

        /**
         * @see QueryBuilderFactory#newQueryBuilder(Class)
         */
        @Override
        public <T> QueryBuilder<T> newQueryBuilder( final Class<T> resultType )
        {
            NotQueryableException.throwIfNotQueryable( resultType );

            final ServiceReference<EntityFinder> serviceReference;
            try
            {
                serviceReference = finder.findService( EntityFinder.class );
                return new QueryBuilderImpl<T>( serviceReference.get(), resultType, null );
            }
            catch( NoSuchServiceException e )
            {
                return new QueryBuilderImpl<T>( null, resultType, null );
            }
        }
    }