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/****************************************************************************
* Sangria *
* Copyright (C) 2014 Tavian Barnes <tavianator@tavianator.com> *
* *
* Licensed under the Apache License, Version 2.0 (the "License"); *
* you may not use this file except in compliance with the License. *
* You may obtain a copy of the License at *
* *
* http://www.apache.org/licenses/LICENSE-2.0 *
* *
* Unless required by applicable law or agreed to in writing, software *
* distributed under the License is distributed on an "AS IS" BASIS, *
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
* See the License for the specific language governing permissions and *
* limitations under the License. *
****************************************************************************/
package com.tavianator.sangria.lazy;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.*;
import javax.inject.Inject;
import javax.inject.Qualifier;
import javax.inject.Singleton;
import com.google.inject.AbstractModule;
import com.google.inject.Binding;
import com.google.inject.CreationException;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Module;
import com.google.inject.ProvidedBy;
import com.google.inject.Provider;
import com.google.inject.spi.DefaultBindingTargetVisitor;
import com.google.inject.spi.Element;
import com.google.inject.spi.Elements;
import com.google.inject.util.Providers;
import org.junit.Test;
import static com.tavianator.sangria.test.SangriaMatchers.*;
import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;
/**
* Tests for {@link Lazy} injection.
*
* @author Tavian Barnes (tavianator@tavianator.com)
* @version 1.3
* @since 1.2
*/
public class LazyTest {
@Retention(RetentionPolicy.RUNTIME)
@Qualifier
private @interface Simple {
}
@ProvidedBy(CountingProvider.class)
private interface Abstract {
}
@Singleton
private static class CountingProvider implements Provider<Abstract> {
int count = 0;
private final Provider<Abstract> impl;
@Inject
CountingProvider() {
this.impl = new Provider<Abstract>() {
@Override
public Abstract get() {
return new Abstract() { };
}
};
}
CountingProvider(Abstract instance) {
this.impl = Providers.of(instance);
}
@Override
public Abstract get() {
++count;
return impl.get();
}
}
private static class HasLazy {
final Lazy<Abstract> lazy;
@Inject
HasLazy(Lazy<Abstract> lazy) {
this.lazy = lazy;
}
}
private static class HasSimpleLazy extends HasLazy {
@Inject
HasSimpleLazy(@Simple Lazy<Abstract> lazy) {
super(lazy);
}
}
private void test(Injector injector, Class<? extends HasLazy> type) {
CountingProvider provider = injector.getInstance(CountingProvider.class);
HasLazy hasLazy = injector.getInstance(type);
assertThat(provider.count, equalTo(0));
Abstract a = hasLazy.lazy.get();
assertThat(provider.count, equalTo(1));
assertThat(hasLazy.lazy.get(), sameInstance(a));
assertThat(provider.count, equalTo(1));
hasLazy = injector.getInstance(type);
assertThat(provider.count, equalTo(1));
a = hasLazy.lazy.get();
assertThat(provider.count, equalTo(2));
assertThat(hasLazy.lazy.get(), sameInstance(a));
assertThat(provider.count, equalTo(2));
}
@Test
public void testJustInTime() {
test(Guice.createInjector(), HasLazy.class);
}
private static final Module EXPLICIT_MODULE = new AbstractModule() {
@Override
protected void configure() {
bind(Abstract.class)
.toProvider(CountingProvider.class);
LazyBinder.create(binder())
.bind(Abstract.class);
bind(HasLazy.class);
}
};
@Test
public void testExplicitBindings() {
test(Guice.createInjector(EXPLICIT_MODULE), HasLazy.class);
}
private static final Module BIND_SEPARATELY_MODULE = new AbstractModule() {
@Override
protected void configure() {
bind(Abstract.class)
.annotatedWith(Simple.class)
.toProvider(CountingProvider.class);
LazyBinder.create(binder())
.bind(Abstract.class)
.annotatedWith(Simple.class);
bind(HasSimpleLazy.class);
}
};
@Test
public void testBindSeparately() {
test(Guice.createInjector(BIND_SEPARATELY_MODULE), HasSimpleLazy.class);
}
private static final Module BIND_TOGETHER_MODULE = new AbstractModule() {
@Override
protected void configure() {
LazyBinder.create(binder())
.bind(Abstract.class)
.annotatedWith(Simple.class)
.toProvider(CountingProvider.class);
bind(HasSimpleLazy.class);
}
};
@Test
public void testBindTogether() {
test(Guice.createInjector(BIND_TOGETHER_MODULE), HasSimpleLazy.class);
}
@Test
public void testBestPractices() {
Module module = new AbstractModule() {
@Override
protected void configure() {
install(EXPLICIT_MODULE);
install(BIND_SEPARATELY_MODULE);
install(BIND_TOGETHER_MODULE);
}
};
assertThat(module, is(atomic()));
assertThat(module, followsBestPractices());
}
@Test
public void testNull() {
Module module = new AbstractModule() {
@Override
protected void configure() {
bind(CountingProvider.class)
.toInstance(new CountingProvider(null));
}
};
test(Guice.createInjector(module), HasLazy.class);
}
@Test(expected = CreationException.class)
public void testMissingBinding() {
Guice.createInjector(new AbstractModule() {
@Override
protected void configure() {
LazyBinder.create(binder())
.bind(Abstract.class)
.annotatedWith(Simple.class);
}
});
}
private static class TestVisitor<T> extends DefaultBindingTargetVisitor<T, Boolean> implements LazyBindingVisitor<T, Boolean> {
@Override
public Boolean visit(LazyBinding<? extends T> binding) {
assertThat(binding.getTargetKey().equals(new Key<Abstract>(Simple.class) { }), is(true));
return true;
}
@Override
protected Boolean visitOther(Binding<? extends T> binding) {
return false;
}
}
private <T> boolean visit(Binding<T> binding) {
return binding.acceptTargetVisitor(new TestVisitor<T>());
}
@Test
public void testExtensionSpi() {
Module module = new AbstractModule() {
@Override
protected void configure() {
// TODO: Expose the SPI for unqualified bindings
LazyBinder.create(binder())
.bind(Abstract.class)
.annotatedWith(Simple.class)
.toProvider(CountingProvider.class);
}
};
List<Element> elements = Elements.getElements(module);
int passed = 0;
for (Element element : elements) {
if (element instanceof Binding) {
if (visit((Binding<?>)element)) {
++passed;
}
}
}
assertThat(passed, equalTo(1));
Injector injector = Guice.createInjector(Elements.getModule(elements));
assertThat(visit(injector.getBinding(new Key<Lazy<Abstract>>(Simple.class) { })), is(true));
assertThat(visit(injector.getBinding(new Key<Abstract>(Simple.class) { })), is(false));
}
}
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