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.object.defaults;
021
022import org.apache.isis.applib.adapters.DefaultsProvider;
023import org.apache.isis.applib.adapters.EncoderDecoder;
024import org.apache.isis.core.commons.lang.ClassExtensions;
025import org.apache.isis.core.metamodel.facetapi.FacetAbstract;
026import org.apache.isis.core.metamodel.facetapi.FacetHolder;
027import org.apache.isis.core.metamodel.runtimecontext.ServicesInjector;
028
029public abstract class DefaultedFacetAbstract extends FacetAbstract implements DefaultedFacet {
030
031    private final Class<?> defaultsProviderClass;
032
033    // to delegate to
034    private final DefaultedFacetUsingDefaultsProvider defaultedFacetUsingDefaultsProvider;
035
036    private final ServicesInjector dependencyInjector;
037
038    public DefaultedFacetAbstract(final String candidateEncoderDecoderName, final Class<?> candidateEncoderDecoderClass, final FacetHolder holder, final ServicesInjector dependencyInjector) {
039        super(DefaultedFacet.class, holder, Derivation.NOT_DERIVED);
040
041        this.defaultsProviderClass = DefaultsProviderUtil.defaultsProviderOrNull(candidateEncoderDecoderClass, candidateEncoderDecoderName);
042        this.dependencyInjector = dependencyInjector;
043        if (isValid()) {
044            final DefaultsProvider<?> defaultsProvider = (DefaultsProvider<?>) ClassExtensions.newInstance(defaultsProviderClass, FacetHolder.class, holder);
045            this.defaultedFacetUsingDefaultsProvider = new DefaultedFacetUsingDefaultsProvider(defaultsProvider, holder, getDependencyInjector());
046        } else {
047            this.defaultedFacetUsingDefaultsProvider = null;
048        }
049    }
050
051    /**
052     * Discover whether either of the candidate defaults provider name or class
053     * is valid.
054     */
055    public boolean isValid() {
056        return defaultsProviderClass != null;
057    }
058
059    /**
060     * Guaranteed to implement the {@link EncoderDecoder} class, thanks to
061     * generics in the applib.
062     */
063    public Class<?> getDefaultsProviderClass() {
064        return defaultsProviderClass;
065    }
066
067    @Override
068    public Object getDefault() {
069        return defaultedFacetUsingDefaultsProvider.getDefault();
070    }
071
072    @Override
073    protected String toStringValues() {
074        return defaultsProviderClass.getName();
075    }
076
077    // //////////////////////////////////////////////////////
078    // Dependencies (from constructor)
079    // //////////////////////////////////////////////////////
080
081    private ServicesInjector getDependencyInjector() {
082        return dependencyInjector;
083    }
084
085}