dagger2.internal.codegen.ContributionBinding.java Source code

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Here is the source code for dagger2.internal.codegen.ContributionBinding.java

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/*
 * Copyright (C) 2014 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 dagger2.internal.codegen;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableListMultimap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;
import java.util.EnumSet;
import java.util.Set;
import javax.inject.Provider;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.DeclaredType;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

/**
 * An abstract class for a value object representing the mechanism by which a {@link Key} can be
 * contributed to a dependency graph.
 *
 * @author Jesse Beder
 * @since 2.0
 */
abstract class ContributionBinding extends Binding {
    static enum BindingType {
        /** Represents map bindings. */
        MAP,
        /** Represents set bindings. */
        SET,
        /** Represents a valid non-collection binding. */
        UNIQUE;

        boolean isMultibinding() {
            return !this.equals(UNIQUE);
        }
    }

    abstract BindingType bindingType();

    /** Returns the type that specifies this' nullability, absent if not nullable. */
    abstract Optional<DeclaredType> nullableType();

    /**
     * If this is a provision request from an {@code @Provides} or {@code @Produces} method, this will
     * be the element that contributed it. In the case of subclassed modules, this may differ than the
     * binding's enclosed element, as this will return the subclass whereas the enclosed element will
     * be the superclass.
     */
    abstract Optional<TypeElement> contributedBy();

    /**
     * Returns whether this binding is synthetic, i.e., not explicitly tied to code, but generated
     * implicitly by the framework.
     */
    // TODO(user): Remove the SYNTHETIC enums from ProvisionBinding and ProductionBinding and make
    // this field the source of truth for synthetic bindings.
    abstract boolean isSyntheticBinding();

    /**
     * Returns the framework class associated with this binding, e.g., {@link Provider} for a
     * ProvisionBinding.
     */
    abstract Class<?> frameworkClass();

    /**
     * Returns the set of {@link BindingType} enum values implied by a given
     * {@link ContributionBinding} collection.
     */
    static <B extends ContributionBinding> ImmutableListMultimap<BindingType, B> bindingTypesFor(
            Iterable<? extends B> bindings) {
        ImmutableListMultimap.Builder<BindingType, B> builder = ImmutableListMultimap.builder();
        builder.orderKeysBy(Ordering.<BindingType>natural());
        for (B binding : bindings) {
            builder.put(binding.bindingType(), binding);
        }
        return builder.build();
    }

    /**
     * Returns a single {@code BindingsType} represented by a given collection of
     * {@code ContributionBindings} or throws an IllegalArgumentException if the given bindings
     * are not all of one type.
     */
    static BindingType bindingTypeFor(Iterable<? extends ContributionBinding> bindings) {
        checkNotNull(bindings);
        checkArgument(!Iterables.isEmpty(bindings), "no bindings");
        Set<BindingType> types = EnumSet.noneOf(BindingType.class);
        for (ContributionBinding binding : bindings) {
            types.add(binding.bindingType());
        }
        if (types.size() > 1) {
            throw new IllegalArgumentException(String.format(ErrorMessages.MULTIPLE_BINDING_TYPES_FORMAT, types));
        }
        return Iterables.getOnlyElement(types);
    }
}