# CollectionType.java

    /*
     * Copyright (c) 2009, 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.api.type;

    import java.lang.reflect.Type;
    import java.util.Collection;
    import java.util.List;
    import java.util.Set;
    import org.qi4j.api.util.Classes;

    /**
     * Collection ValueType.
     * <p>This handles Collection, List and Set types.</p>
     */
    public final class CollectionType
        extends ValueType
    {

        public static boolean isCollection( Type type )
        {
            Class<?> cl = Classes.RAW_CLASS.map( type );
            return cl.equals( Collection.class ) || cl.equals( List.class ) || cl.equals( Set.class );
        }

        public static CollectionType collectionOf( Class<?> collectedType )
        {
            return new CollectionType( Collection.class, ValueType.of( collectedType ) );
        }

        public static CollectionType listOf( Class<?> collectedType )
        {
            return new CollectionType( List.class, ValueType.of( collectedType ) );
        }

        public static CollectionType setOf( Class<?> collectedType )
        {
            return new CollectionType( Set.class, ValueType.of( collectedType ) );
        }
        private ValueType collectedType;

        public CollectionType( Class<?> type, ValueType collectedType )
        {
            super( type );
            this.collectedType = collectedType;
            if( !isCollection( type ) )
            {
                throw new IllegalArgumentException( type + " is not a Collection, List or Set." );
            }
        }

        public ValueType collectedType()
        {
            return collectedType;
        }

        @Override
        public String toString()
        {
            return super.toString() + "<" + collectedType + ">";
        }
    }