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.named.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.named.staticmethod.NamedFacetViaMethod;
038
039/**
040 * Sets up all the {@link Facet}s for an action in a single shot.
041 */
042public class ActionParameterNamesMethodFacetFactory extends MethodPrefixBasedFacetFactoryAbstract {
043
044    private static final String[] PREFIXES = { MethodPrefixConstants.NAME_PREFIX };
045
046    /**
047     * Note that the {@link Facet}s registered are the generic ones from
048     * noa-architecture (where they exist)
049     */
050    public ActionParameterNamesMethodFacetFactory() {
051        super(FeatureType.ACTIONS_ONLY, OrphanValidation.VALIDATE, PREFIXES);
052    }
053
054    // ///////////////////////////////////////////////////////
055    // Actions
056    // ///////////////////////////////////////////////////////
057
058    @Override
059    public void process(final ProcessMethodContext processMethodContext) {
060
061        final FacetedMethod facetedMethod = processMethodContext.getFacetHolder();
062        final List<FacetedMethodParameter> holderList = facetedMethod.getParameters();
063
064        attachNamedFacetForParametersIfParameterNamesMethodIsFound(processMethodContext, holderList);
065    }
066
067    private static void attachNamedFacetForParametersIfParameterNamesMethodIsFound(final ProcessMethodContext processMethodContext, final List<FacetedMethodParameter> parameters) {
068
069        if (parameters.isEmpty()) {
070            return;
071        }
072
073        final Method actionMethod = processMethodContext.getMethod();
074        final String capitalizedName = StringExtensions.asCapitalizedName(actionMethod.getName());
075
076        final Class<?> cls = processMethodContext.getCls();
077        final Method namesMethod = MethodFinderUtils.findMethod(cls, MethodScope.CLASS, MethodPrefixConstants.NAME_PREFIX + capitalizedName, String[].class, new Class[0]);
078        if (namesMethod == null) {
079            return;
080        }
081        try {
082            final String[] names = invokeNamesMethod(namesMethod, parameters.size());
083            for (int i = 0; i < names.length; i++) {
084                // add facets directly to parameters, not to actions
085                FacetUtil.addFacet(new NamedFacetViaMethod(names[i], namesMethod, parameters.get(i)));
086            }
087        } finally {
088            processMethodContext.removeMethod(namesMethod);
089        }
090    }
091
092    private static String[] invokeNamesMethod(final Method namesMethod, final int numElementsRequired) {
093        String[] names = null;
094        try {
095            names = (String[]) MethodExtensions.invokeStatic(namesMethod, new Object[0]);
096        } catch (final ClassCastException ex) {
097            // ignore
098        }
099        if (names == null || names.length != numElementsRequired) {
100            throw new MetaModelException(namesMethod + " must return an String[] array of same size as number of parameters of action");
101        }
102        return names;
103    }
104}