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
020package org.apache.isis.core.progmodel.facets.param.describedas.staticmethod;
021
022import java.lang.reflect.Method;
023import java.util.List;
024
025import org.apache.isis.core.commons.lang.MethodExtensions;
026import org.apache.isis.core.commons.lang.StringExtensions;
027import org.apache.isis.core.metamodel.exceptions.MetaModelException;
028import org.apache.isis.core.metamodel.facetapi.Facet;
029import org.apache.isis.core.metamodel.facetapi.FacetUtil;
030import org.apache.isis.core.metamodel.facetapi.FeatureType;
031import org.apache.isis.core.metamodel.facets.FacetedMethod;
032import org.apache.isis.core.metamodel.facets.FacetedMethodParameter;
033import org.apache.isis.core.metamodel.methodutils.MethodScope;
034import org.apache.isis.core.progmodel.facets.MethodFinderUtils;
035import org.apache.isis.core.progmodel.facets.MethodPrefixBasedFacetFactoryAbstract;
036import org.apache.isis.core.progmodel.facets.MethodPrefixConstants;
037import org.apache.isis.core.progmodel.facets.members.describedas.staticmethod.DescribedAsFacetViaMethod;
038
039public class ActionParameterDescriptionsMethodFacetFactory extends MethodPrefixBasedFacetFactoryAbstract {
040
041    private static final String[] PREFIXES = { MethodPrefixConstants.DESCRIPTION_PREFIX };
042
043    /**
044     * Note that the {@link Facet}s registered are the generic ones from
045     * noa-architecture (where they exist)
046     */
047    public ActionParameterDescriptionsMethodFacetFactory() {
048        super(FeatureType.ACTIONS_ONLY, OrphanValidation.VALIDATE, PREFIXES);
049    }
050
051    // ///////////////////////////////////////////////////////
052    // Actions
053    // ///////////////////////////////////////////////////////
054
055    @Override
056    public void process(final ProcessMethodContext processMethodContext) {
057
058        final FacetedMethod facetedMethod = processMethodContext.getFacetHolder();
059        final List<FacetedMethodParameter> holderList = facetedMethod.getParameters();
060
061        attachDescribedAsFacetForParametersIfParameterDescriptionsMethodIsFound(processMethodContext, holderList);
062    }
063
064    private static void attachDescribedAsFacetForParametersIfParameterDescriptionsMethodIsFound(final ProcessMethodContext processMethodContext, final List<FacetedMethodParameter> parameters) {
065
066        if (parameters.isEmpty()) {
067            return;
068        }
069
070        final Method actionMethod = processMethodContext.getMethod();
071
072        final String capitalizedName = StringExtensions.asCapitalizedName(actionMethod.getName());
073
074        final Class<?> cls = processMethodContext.getCls();
075        final Method descriptionMethod = MethodFinderUtils.findMethod(cls, MethodScope.CLASS, MethodPrefixConstants.DESCRIPTION_PREFIX + capitalizedName, String[].class, new Class[0]);
076        if (descriptionMethod == null) {
077            return;
078        }
079        processMethodContext.removeMethod(descriptionMethod);
080
081        final String[] descriptions = invokeDescriptionsMethod(descriptionMethod, parameters.size());
082        for (int i = 0; i < descriptions.length; i++) {
083            // add facets directly to parameters, not to actions
084            FacetUtil.addFacet(new DescribedAsFacetViaMethod(descriptions[i], descriptionMethod, parameters.get(i)));
085        }
086    }
087
088    private static String[] invokeDescriptionsMethod(final Method descriptionMethod, final int numElementsRequired) {
089        String[] descriptions = null;
090        try {
091            descriptions = (String[]) MethodExtensions.invokeStatic(descriptionMethod, new Object[0]);
092        } catch (final ClassCastException ex) {
093            // ignore
094        }
095        if (descriptions == null || descriptions.length != numElementsRequired) {
096            throw new MetaModelException(descriptionMethod + " must return an String[] array of same size as number of parameters of action");
097        }
098        return descriptions;
099    }
100
101}