001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one
003     *  or more contributor license agreements.  See the NOTICE file
004     *  distributed with this work for additional information
005     *  regarding copyright ownership.  The ASF licenses this file
006     *  to you under the Apache License, Version 2.0 (the
007     *  "License"); you may not use this file except in compliance
008     *  with the License.  You may obtain a copy of the License at
009     *
010     *        http://www.apache.org/licenses/LICENSE-2.0
011     *
012     *  Unless required by applicable law or agreed to in writing,
013     *  software distributed under the License is distributed on an
014     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     *  KIND, either express or implied.  See the License for the
016     *  specific language governing permissions and limitations
017     *  under the License.
018     */
019    
020    package org.apache.isis.core.progmodel.facets.object.validperspec;
021    
022    import java.util.ArrayList;
023    import java.util.List;
024    
025    import org.apache.isis.applib.annotation.MustSatisfy;
026    import org.apache.isis.applib.spec.Specification;
027    import org.apache.isis.core.metamodel.facetapi.Facet;
028    import org.apache.isis.core.metamodel.facetapi.FacetHolder;
029    import org.apache.isis.core.metamodel.facetapi.FacetUtil;
030    import org.apache.isis.core.metamodel.facetapi.FeatureType;
031    import org.apache.isis.core.metamodel.facets.AnnotationBasedFacetFactoryAbstract;
032    
033    public class MustSatisfySpecificationOnTypeFacetFactory extends AnnotationBasedFacetFactoryAbstract {
034    
035        public MustSatisfySpecificationOnTypeFacetFactory() {
036            super(FeatureType.OBJECTS_ONLY);
037        }
038    
039        @Override
040        public void process(final ProcessClassContext processClassContaxt) {
041            FacetUtil.addFacet(create(processClassContaxt.getCls(), processClassContaxt.getFacetHolder()));
042        }
043    
044        private Facet create(final Class<?> clazz, final FacetHolder holder) {
045            return create(getAnnotation(clazz, MustSatisfy.class), holder);
046        }
047    
048        private static Facet create(final MustSatisfy annotation, final FacetHolder holder) {
049            if (annotation == null) {
050                return null;
051            }
052            final Class<?>[] values = annotation.value();
053            final List<Specification> specifications = new ArrayList<Specification>();
054            for (final Class<?> value : values) {
055                final Specification specification = newSpecificationElseNull(value);
056                if (specification != null) {
057                    specifications.add(specification);
058                }
059            }
060            return specifications.size() > 0 ? new MustSatisfySpecificationOnTypeFacet(specifications, holder) : null;
061        }
062    
063        private static Specification newSpecificationElseNull(final Class<?> value) {
064            if (!(Specification.class.isAssignableFrom(value))) {
065                return null;
066            }
067            try {
068                return (Specification) value.newInstance();
069            } catch (final InstantiationException e) {
070                return null;
071            } catch (final IllegalAccessException e) {
072                return null;
073            }
074        }
075    
076    }