| /** |
| * Copyright (C) 2008 Google Inc. |
| * |
| * 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.google.inject.util; |
| |
| import com.google.inject.AbstractModule; |
| import com.google.inject.Binder; |
| import com.google.inject.Binding; |
| import com.google.inject.Key; |
| import com.google.inject.Module; |
| import com.google.inject.Scope; |
| import com.google.inject.PrivateBinder; |
| import com.google.inject.internal.ImmutableSet; |
| import com.google.inject.internal.Lists; |
| import com.google.inject.internal.Maps; |
| import com.google.inject.internal.Sets; |
| import com.google.inject.spi.DefaultBindingScopingVisitor; |
| import com.google.inject.spi.DefaultElementVisitor; |
| import com.google.inject.spi.Element; |
| import com.google.inject.spi.Elements; |
| import com.google.inject.spi.ScopeBinding; |
| import com.google.inject.spi.PrivateElements; |
| import java.lang.annotation.Annotation; |
| import java.util.Arrays; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * Static utility methods for creating and working with instances of {@link Module}. |
| * |
| * @author jessewilson@google.com (Jesse Wilson) |
| * @since 2.0 |
| */ |
| public final class Modules { |
| private Modules() {} |
| |
| public static final Module EMPTY_MODULE = new Module() { |
| public void configure(Binder binder) {} |
| }; |
| |
| /** |
| * Returns a builder that creates a module that overlays override modules over the given |
| * modules. If a key is bound in both sets of modules, only the binding from the override modules |
| * is kept. This can be used to replace the bindings of a production module with test bindings: |
| * <pre> |
| * Module functionalTestModule |
| * = Modules.override(new ProductionModule()).with(new TestModule()); |
| * </pre> |
| * |
| * <p>Prefer to write smaller modules that can be reused and tested without overrides. |
| * |
| * @param modules the modules whose bindings are open to be overridden |
| */ |
| public static OverriddenModuleBuilder override(Module... modules) { |
| return new RealOverriddenModuleBuilder(Arrays.asList(modules)); |
| } |
| |
| /** |
| * Returns a builder that creates a module that overlays override modules over the given |
| * modules. If a key is bound in both sets of modules, only the binding from the override modules |
| * is kept. This can be used to replace the bindings of a production module with test bindings: |
| * <pre> |
| * Module functionalTestModule |
| * = Modules.override(getProductionModules()).with(getTestModules()); |
| * </pre> |
| * |
| * <p>Prefer to write smaller modules that can be reused and tested without overrides. |
| * |
| * @param modules the modules whose bindings are open to be overridden |
| */ |
| public static OverriddenModuleBuilder override(Iterable<? extends Module> modules) { |
| return new RealOverriddenModuleBuilder(modules); |
| } |
| |
| /** |
| * Returns a new module that installs all of {@code modules}. |
| */ |
| public static Module combine(Module... modules) { |
| return combine(ImmutableSet.of(modules)); |
| } |
| |
| /** |
| * Returns a new module that installs all of {@code modules}. |
| */ |
| public static Module combine(Iterable<? extends Module> modules) { |
| final Set<Module> modulesSet = ImmutableSet.copyOf(modules); |
| return new Module() { |
| public void configure(Binder binder) { |
| binder = binder.skipSources(getClass()); |
| for (Module module : modulesSet) { |
| binder.install(module); |
| } |
| } |
| }; |
| } |
| |
| /** |
| * See the EDSL example at {@link Modules#override(Module[]) override()}. |
| */ |
| public interface OverriddenModuleBuilder { |
| |
| /** |
| * See the EDSL example at {@link Modules#override(Module[]) override()}. |
| */ |
| Module with(Module... overrides); |
| |
| /** |
| * See the EDSL example at {@link Modules#override(Module[]) override()}. |
| */ |
| Module with(Iterable<? extends Module> overrides); |
| } |
| |
| private static final class RealOverriddenModuleBuilder implements OverriddenModuleBuilder { |
| private final ImmutableSet<Module> baseModules; |
| |
| private RealOverriddenModuleBuilder(Iterable<? extends Module> baseModules) { |
| this.baseModules = ImmutableSet.copyOf(baseModules); |
| } |
| |
| public Module with(Module... overrides) { |
| return with(Arrays.asList(overrides)); |
| } |
| |
| public Module with(final Iterable<? extends Module> overrides) { |
| return new AbstractModule() { |
| @Override |
| public void configure() { |
| final List<Element> elements = Elements.getElements(baseModules); |
| final List<Element> overrideElements = Elements.getElements(overrides); |
| |
| final Set<Key<?>> overriddenKeys = Sets.newHashSet(); |
| final Set<Class<? extends Annotation>> overridesScopeAnnotations = Sets.newHashSet(); |
| |
| // execute the overrides module, keeping track of which keys and scopes are bound |
| new ModuleWriter(binder()) { |
| @Override public <T> Void visit(Binding<T> binding) { |
| overriddenKeys.add(binding.getKey()); |
| return super.visit(binding); |
| } |
| |
| @Override public Void visit(ScopeBinding scopeBinding) { |
| overridesScopeAnnotations.add(scopeBinding.getAnnotationType()); |
| return super.visit(scopeBinding); |
| } |
| |
| @Override public Void visit(PrivateElements privateElements) { |
| overriddenKeys.addAll(privateElements.getExposedKeys()); |
| return super.visit(privateElements); |
| } |
| }.writeAll(overrideElements); |
| |
| // execute the original module, skipping all scopes and overridden keys. We only skip each |
| // overridden binding once so things still blow up if the module binds the same thing |
| // multiple times. |
| final Map<Scope, Object> scopeInstancesInUse = Maps.newHashMap(); |
| final List<ScopeBinding> scopeBindings = Lists.newArrayList(); |
| new ModuleWriter(binder()) { |
| @Override public <T> Void visit(Binding<T> binding) { |
| if (!overriddenKeys.remove(binding.getKey())) { |
| super.visit(binding); |
| |
| // Record when a scope instance is used in a binding |
| Scope scope = getScopeInstanceOrNull(binding); |
| if (scope != null) { |
| scopeInstancesInUse.put(scope, binding.getSource()); |
| } |
| } |
| |
| return null; |
| } |
| |
| void rewrite(Binder binder, PrivateElements privateElements, Set<Key<?>> keysToSkip) { |
| PrivateBinder privateBinder = binder.withSource(privateElements.getSource()) |
| .newPrivateBinder(); |
| |
| Set<Key<?>> skippedExposes = Sets.newHashSet(); |
| |
| for (Key<?> key : privateElements.getExposedKeys()) { |
| if (keysToSkip.remove(key)) { |
| skippedExposes.add(key); |
| } else { |
| privateBinder.withSource(privateElements.getExposedSource(key)).expose(key); |
| } |
| } |
| |
| for (Element element : privateElements.getElements()) { |
| if (element instanceof Binding |
| && skippedExposes.remove(((Binding) element).getKey())) { |
| continue; |
| } |
| if (element instanceof PrivateElements) { |
| rewrite(privateBinder, (PrivateElements) element, skippedExposes); |
| continue; |
| } |
| element.applyTo(privateBinder); |
| } |
| } |
| |
| @Override public Void visit(PrivateElements privateElements) { |
| rewrite(binder, privateElements, overriddenKeys); |
| return null; |
| } |
| |
| @Override public Void visit(ScopeBinding scopeBinding) { |
| scopeBindings.add(scopeBinding); |
| return null; |
| } |
| }.writeAll(elements); |
| |
| // execute the scope bindings, skipping scopes that have been overridden. Any scope that |
| // is overridden and in active use will prompt an error |
| new ModuleWriter(binder()) { |
| @Override public Void visit(ScopeBinding scopeBinding) { |
| if (!overridesScopeAnnotations.remove(scopeBinding.getAnnotationType())) { |
| super.visit(scopeBinding); |
| } else { |
| Object source = scopeInstancesInUse.get(scopeBinding.getScope()); |
| if (source != null) { |
| binder().withSource(source).addError( |
| "The scope for @%s is bound directly and cannot be overridden.", |
| scopeBinding.getAnnotationType().getSimpleName()); |
| } |
| } |
| return null; |
| } |
| }.writeAll(scopeBindings); |
| |
| // TODO: bind the overridden keys using multibinder |
| } |
| |
| private Scope getScopeInstanceOrNull(Binding<?> binding) { |
| return binding.acceptScopingVisitor(new DefaultBindingScopingVisitor<Scope>() { |
| public Scope visitScope(Scope scope) { |
| return scope; |
| } |
| }); |
| } |
| }; |
| } |
| } |
| |
| private static class ModuleWriter extends DefaultElementVisitor<Void> { |
| protected final Binder binder; |
| |
| ModuleWriter(Binder binder) { |
| this.binder = binder; |
| } |
| |
| @Override protected Void visitOther(Element element) { |
| element.applyTo(binder); |
| return null; |
| } |
| |
| void writeAll(Iterable<? extends Element> elements) { |
| for (Element element : elements) { |
| element.acceptVisitor(this); |
| } |
| } |
| } |
| } |