1 /**
2 * This file Copyright (c) 2017-2018 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.i18nsystem.util.AnnotationUtils;
37 import info.magnolia.objectfactory.Components;
38 import info.magnolia.objectfactory.annotation.LazySingleton;
39
40 import java.lang.annotation.Annotation;
41 import java.util.ArrayList;
42 import java.util.HashMap;
43 import java.util.List;
44 import java.util.Map;
45
46 import javax.inject.Singleton;
47
48 import com.google.inject.AbstractModule;
49 import com.google.inject.Binding;
50 import com.google.inject.Module;
51 import com.google.inject.spi.Element;
52 import com.google.inject.spi.Elements;
53
54 /**
55 * Detects the bindings which involve types annotated with {@link Singleton} and
56 * {@link info.magnolia.objectfactory.annotation.LazySingleton} and will suppress their impact by driving the bindings
57 * to more narrow UI-related scopes.
58 * <p>
59 * E.g. we have a class Foo implemented by FooImpl and FooImpl is marked with @Singleton
60 * annotation. With old ways in Magnolia @Singleton might mean that Foo is an app/sub-app/...
61 * component depending on how foo interface is configured in module descriptor. However,
62 * in the realm where there's just one Injector for the whole UI singleton means singleton
63 * for the whole web-app. Since the singleton-ness is enforced with annotation it is not easy
64 * to suppress it. However, there is a way.
65 * </p>
66 * <p>
67 * Guice allows sort of chaining the bindings, meaning that if Foo is bound to FooImpl and FooImpl
68 * in turn is bound to FooOtherImpl, the FooOtherImpl will be used when injecting Foo.
69 * Similar trick can be done with the scopes. Scope specified with module API overrides the
70 * scope coming from annotation. Using this capability we will drop the misleading singleton
71 * scope by explicitly mapping impl types (and providers) to the according UI scopes.
72 * </p>
73 */
74 class EliminateRedundantSingletonAnnotations extends AbstractModule {
75
76 private final Module sourceModule;
77
78 EliminateRedundantSingletonAnnotations(Module module) {
79 this.sourceModule = module;
80 }
81
82 @Override
83 protected void configure() {
84
85 // First - collect all the linked bindings (interface <-> impl) and provider bindings
86 // which have the implementations marked with @Singleton
87 final Map<Class, Binding> faultySingletons = new HashMap<>();
88 final List<Element> sourceElements = Elements.getElements(sourceModule);
89
90 // Store elements (bindings) that will have to be re-applied as is
91 final List<Element> elementsToWrite = new ArrayList<>(sourceElements);
92
93 // Inspect linked key bindings and provider key bindings, search for the @Singleton
94 // @LazySingleton annotated types. Aggregate such bindings
95 GuiceSpi.getBindings(sourceElements).forEach(binding ->
96 GuiceSpi.<Class>inspect(binding)
97 .onLinkedBinding(linkedKeyBinding -> linkedKeyBinding.getLinkedKey().getTypeLiteral().getRawType())
98 .onProviderKeyBinding(providerKeyBinding -> providerKeyBinding.getProviderKey().getTypeLiteral().getRawType())
99 .visit()
100 .filter(this::isAnnotatedSingleton)
101 .ifPresent(type -> faultySingletons.put(type, binding)));
102
103 // Suppress the @Singleton and @LazySingleton effect
104 faultySingletons.forEach((type, binding) -> {
105 final UiContextAnnotation uiContextAnnotation = UiAnnotations.cast(binding.getKey().getAnnotation());
106
107 final Class<? extends Annotation> relatedScope = uiContextAnnotation.getRelatedScopeAnnotation(isEagerSingleton(type));
108 GuiceSpi.<Void>inspect(binding)
109
110 .consumeProviderKeyBinding(providerKeyBinding -> {
111 // For singleton provider bound types: explicitly bind the provider to the
112 // appropriate UI scope
113 bind(providerKeyBinding.getProviderKey()).in(relatedScope);
114 // Then bind the key to such provider in the same scope
115 bind(providerKeyBinding.getKey()).toProvider(providerKeyBinding.getProviderKey()).in(relatedScope);
116 })
117
118 .consumeLinkedBinding(linkedKeyBinding -> {
119 // For type <-> impl bindings, use #newInstance-flavored provider to
120 // mascarade the singleton scope
121 // TODO - probably ConstructorBinding would be more appropriate here?
122 bind(linkedKeyBinding.getKey())
123 .toProvider(() -> Components.newInstance(linkedKeyBinding.getLinkedKey().getTypeLiteral().getRawType()))
124 .in(relatedScope);
125 })
126
127 .visit();
128 });
129
130 elementsToWrite.removeAll(faultySingletons.values());
131 elementsToWrite.forEach(element -> element.applyTo(binder()));
132 }
133
134 private boolean isEagerSingleton(Class type) {
135 return AnnotationUtils.hasAnnotationOn(type, com.google.inject.Singleton.class) ||
136 AnnotationUtils.hasAnnotationOn(type, Singleton.class);
137 }
138
139 private boolean isAnnotatedSingleton(Class targetType) {
140 return AnnotationUtils.hasAnnotationOn(targetType, com.google.inject.Singleton.class) ||
141 AnnotationUtils.hasAnnotationOn(targetType, Singleton.class) ||
142 AnnotationUtils.hasAnnotationOn(targetType, LazySingleton.class);
143 }
144 }