# ConstraintsInstance.java

    /*
     * Copyright (c) 2008, Rickard Öberg. All Rights Reserved.
     * Copyright (c) 2009, 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.runtime.composite;

    import java.lang.reflect.Method;
    import java.util.ArrayList;
    import java.util.List;
    import org.qi4j.api.composite.Composite;
    import org.qi4j.api.composite.CompositeInstance;
    import org.qi4j.api.constraint.ConstraintViolation;
    import org.qi4j.api.constraint.ConstraintViolationException;

    import static org.qi4j.functional.Iterables.iterable;

    /**
     * JAVADOC
     */
    public final class ConstraintsInstance
    {
        private final List<ValueConstraintsInstance> valueConstraintsInstances;

        public ConstraintsInstance( List<ValueConstraintsInstance> parameterConstraints )
        {
            valueConstraintsInstances = parameterConstraints;
        }

        @SuppressWarnings( "unchecked" )
        public void checkValid( Object instance, Method method, Object[] params )
            throws ConstraintViolationException
        {
            if( valueConstraintsInstances.isEmpty() )
            {
                return; // No constraints to check
            }

            // Check constraints
            List<ConstraintViolation> violations = null;
            for( int i = 0; i < params.length; i++ )
            {
                Object param = params[ i ];
                List<ConstraintViolation> paramViolations = valueConstraintsInstances.get( i ).checkConstraints( param );
                if( !paramViolations.isEmpty() )
                {
                    if( violations == null )
                    {
                        violations = new ArrayList<>();
                    }
                    violations.addAll( paramViolations );
                }
            }

            // Check if any constraint failed
            if( violations != null )
            {
                if( instance instanceof Composite )
                {
                    throw new ConstraintViolationException( (Composite) instance, method, violations );
                }
                if( instance instanceof CompositeInstance )
                {
                    throw new ConstraintViolationException( (Composite) ( (CompositeInstance) instance ).proxy(), method, violations );
                }
                Iterable<? extends Class<?>> types = iterable( instance.getClass() );
                throw new ConstraintViolationException( instance.toString(), (Iterable<Class<?>>) types, method, violations );
            }
        }
    }