# NoSuchEntityException.java

    /*
     * Copyright (c) 2008-2013, Niclas Hedhman. 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.api.unitofwork;

    import org.qi4j.api.entity.EntityReference;
    import org.qi4j.api.usecase.Usecase;
    import org.qi4j.functional.Function;
    import org.qi4j.functional.Iterables;

    /**
     * This exception indicates that the requested Entity with the given
     * identity does not exist.
     */
    public class NoSuchEntityException
        extends UnitOfWorkException
    {
        private final EntityReference identity;
        private final Usecase usecase;
        private final Class<?>[] mixinTypes;

        public NoSuchEntityException( EntityReference identity, Class<?> mixinType, Usecase usecase )
        {
            super( "Could not find entity (" + identity + ") of type " + mixinType.getName() + " in usecase '" + usecase.name() + "'" );
            this.identity = identity;
            this.usecase = usecase;
            this.mixinTypes = new Class<?>[]{ mixinType };
        }

        public NoSuchEntityException( EntityReference identity, Class<?>[] mixinTypes, Usecase usecase )
        {
            super( "Could not find entity (" + identity + ") of type " + toString( mixinTypes ) + " in usecase '" + usecase.name() + "'" );
            this.identity = identity;
            this.mixinTypes = mixinTypes;
            this.usecase = usecase;
        }

        public NoSuchEntityException( EntityReference identity, Iterable<Class<?>> types, Usecase usecase )
        {
            this( identity, castToArray( types ), usecase );
        }

        public EntityReference identity()
        {
            return identity;
        }

        public Class<?>[] mixinTypes()
        {
            return mixinTypes;
        }

        public Usecase usecase()
        {
            return usecase;
        }

        private static Class<?>[] castToArray( Iterable<Class<?>> iterableClasses )
        {
            Iterable<Class> types = Iterables.cast( iterableClasses );
            return Iterables.toArray( Class.class, types );
        }

        private static String toString( Class<?>[] mixinTypes )
        {
            Iterable<String> map = Iterables.map( new Function<Class<?>, String>()
            {
                @Override
                public String map( Class<?> item )
                {
                    return item.getName();
                }
            }, Iterables.iterable( mixinTypes ) );
            return Iterables.fold( new Function<String, String>()
            {
                StringBuilder result;
                boolean first = true;

                {
                    result = new StringBuilder();
                    result.append( "[" );
                }

                @Override
                public String map( String strings )
                {
                    if( !first )
                    {
                        result.append( ',' );
                    }
                    first = false;
                    result.append( strings );
                    return result.toString() + "]";
                }
            }, map );
        }
    }