# InstanceOfConstraint.java

    /*
     * Copyright (c) 2007, 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.library.constraints;

    import org.qi4j.api.constraint.Constraint;
    import org.qi4j.library.constraints.annotation.InstanceOf;

    /**
     * Implement @InstanceOf constraint.
     */
    public class InstanceOfConstraint
        implements Constraint<InstanceOf, Object>
    {

        private static final long serialVersionUID = 1L;

        @Override
        public boolean isValid( InstanceOf annotation, Object parameter )
            throws NullPointerException
        {
            if( parameter != null )
            {
                for( Class aClass : annotation.value() )
                {
                    if( !aClass.isInstance( parameter ) )
                    {
                        return false;
                    }
                }
            }
            return true;
        }

    }