1 /**
2 * This file Copyright (c) 2016-2018 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.ui.framework.ioc;
35
36 import info.magnolia.objectfactory.guice.GuiceComponentProvider;
37 import info.magnolia.objectfactory.guice.GuiceUtils;
38 import info.magnolia.ui.api.ioc.AdminCentral;
39 import info.magnolia.ui.datasource.DatasourceDefinition;
40 import info.magnolia.ui.framework.ioc.DatasourceComponent.DatasourceComponentImpl;
41
42 import java.util.Optional;
43
44 import javax.inject.Inject;
45
46 import com.google.inject.Injector;
47 import com.google.inject.Key;
48 import com.google.inject.Provider;
49 import com.google.inject.name.Names;
50
51 /**
52 * <p>
53 * Special {@link Provider} implementation which is used
54 * when a certain type is bound differently in different contexts.
55 * </p>
56 * <p>
57 * This would be the case when e.g. app <b>bar</b> configures a type
58 * {@code Foo} to be implemented by {@code FooBarImpl} and app
59 * <b>baz</b> has a binding of {@code Foo} to {@code FooBazImpl}.
60 * </p>
61 * <p>
62 * In order to support such cases we assume that {@code Foo} is bound
63 * in a special way. It is expected that two concrete implementations
64 * of it are bound using a {@link com.google.inject.BindingAnnotation
65 * binding annotation} such as e.g.
66 * {@link info.magnolia.ui.api.ioc.App App}.
67 * </p>
68 * <p>
69 * By binding the un-annotated type to this provider we allow the developers
70 * to inject types like {@code Foo} without explicitly
71 * mentioning the binding annotations.
72 * This provider will use {@link CurrentUiContextReference} to fetch all the
73 * relevant UI contexts and will produce the possible Guice {@link Key keys}.
74 * The most suitable key is then picked, i.e. we pick the binding
75 * which is closest to the current UI context.
76 * </p>
77 *
78 * <p>
79 * For more information on binding annotations, see
80 * <a href="https://github.com/google/guice/wiki/BindingAnnotations">Guice Binding Annotations tutorial</a>.
81 * </p>
82 *
83 * @param <T> type of the provided instance.
84 *
85 * @see UiContextReference
86 * @see UiContextBoundComponentProvider
87 */
88 class UiContextApplyingProvider<T> implements Provider<T> {
89
90 public static <U> UiContextApplyingProvider<U> of(Class<U> type) {
91 return new UiContextApplyingProvider<>(type);
92 }
93
94 private @Inject Injector injector;
95
96 private final Class<T> type;
97
98 UiContextApplyingProvider(Class<T> type) {
99 this.type = type;
100 }
101
102 @Override
103 public T get() {
104 UiContextBoundComponentProvider componentProvider = injector.getInstance(UiContextBoundComponentProvider.class);
105 // get all the UI contexts that are reachable from the current one
106 Key<T> boundKey = componentProvider.getReachableUiContextReferences()
107 // produce a Guice type Key relevant to the UI context
108 .map(uiContextReference -> Key.get(type, uiContextReference.getAnnotation()))
109 // check whether such Key is bound to anything
110 .filter(key -> GuiceUtils.hasExplicitBindingFor(injector, key))
111 .findFirst()
112 .orElseGet(() -> resolveRelatedDataSourceContextKey(type).orElse(null));
113
114 if (boundKey == null) {
115 return getDefault(componentProvider.getComponent(CurrentUiContextReference.class));
116 }
117
118 if (boundKey.getAnnotation() instanceof AdminCentral) {
119 return resolveRelatedDataSourceContextKey(type).map(injector::getInstance).orElseGet(() -> injector.getInstance(boundKey));
120 }
121
122 return injector.getInstance(boundKey);
123
124 }
125
126 private Optional<Key<T>> resolveRelatedDataSourceContextKey(Class<T> type) {
127 return Optional.ofNullable(injector.getInstance(DatasourceDefinition.class))
128 .map(DatasourceDefinition::getName)
129 .map(dsName -> Key.get(type, new DatasourceComponentImpl(dsName)))
130 .filter(key -> GuiceUtils.hasExplicitBindingFor(injector, key));
131 }
132
133
134 private T getDefault(CurrentUiContextReference context) {
135 return Optional.ofNullable(
136 SessionStore.access().getBeanStore(context.getUiContextReference()).get(type))
137 .orElseGet(() -> {
138 try {
139 return this.injector.getInstance(GuiceComponentProvider.class).newInstance(type);
140 } catch (Exception e) {
141 return this.injector.getInstance(Key.get(GuiceComponentProvider.class, Names.named("main"))).getComponent(type);
142 }
143 });
144 }
145 }