com.google.inject.multibindings.MultibinderBinding Maven / Gradle / Ivy

Go to download
package com.google.inject.multibindings;

import com.google.inject.Binding;
import com.google.inject.Key;
import com.google.inject.TypeLiteral;
import com.google.inject.spi.Element;
import com.google.inject.spi.Elements;

import java.util.List;
import java.util.Set;

/**
 * A binding for a Multibinder.
 *
 * @param  The fully qualified type of the set, including Set. For example:
 *            MultibinderBinding<Set<Boolean>>
 */
public interface MultibinderBinding {

    /**
     * Returns the key for the set.
     */
    Key getSetKey();

    /**
     * Returns the keys of other bindings that represent this set. This will return an entry for
     * {@code Collection>} and {@code
     * Collection>}.
     */
    Set> getAlternateSetKeys();

    /**
     * Returns the TypeLiteral that describes the type of elements in the set.
     * 
     * The elements will always match the type Set's generic type. For example, if getSetKey returns a
     * key of Set<String>, then this will always return a
     * TypeLiteral<String>.
     */
    TypeLiteral getElementTypeLiteral();

    /**
     * Returns all bindings that make up the set. This is only supported on bindings returned from an
     * injector. This will throw {@link UnsupportedOperationException} if it is called on an element
     * retrieved from {@link Elements#getElements}.
     * 

     * The elements will always match the type Set's generic type. For example, if getSetKey returns a
     * key of Set<String>, then this will always return a list of type
     * List<Binding<String>>.
     */
    List> getElements();

    /**
     * Returns true if the multibinder permits duplicates. This is only supported on bindings returned
     * from an injector. This will throw {@link UnsupportedOperationException} if it is called on a
     * MultibinderBinding retrieved from {@link Elements#getElements}.
     */
    boolean permitsDuplicates();

    /**
     * Returns true if this Multibinder uses the given Element. This will be true for bindings that
     * derive the elements of the set and other bindings that Multibinder uses internally. This will
     * work for MultibinderBindings retrieved from an injector and {@link Elements#getElements}.
     * Usually this is only necessary if you are working with elements retrieved from modules (without
     * an Injector), otherwise {@link #getElements} and {@link #permitsDuplicates} are better options.
     * 
     * If you need to introspect the details of the set, such as the values or if it permits
     * duplicates, it is necessary to pass the elements through an Injector and use
     * {@link #getElements()} and {@link #permitsDuplicates()}.
     */
    boolean containsElement(Element element);
}