core-common/src/main/java/org/glassfish/jersey/internal/inject/AbstractBinder.java

/*
 * Copyright (c) 2017, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.jersey.internal.inject;

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Objects;
import java.util.function.Supplier;
import java.util.stream.Collectors;

import javax.ws.rs.core.GenericType;

import javax.inject.Provider;

import org.glassfish.jersey.internal.LocalizationMessages;

/**
 * Implementation of {@link Binder} interface dedicated to keep some level of code compatibility between previous HK2
 * implementation and new DI SPI.
 * <p>
 * Currently, there are supported only bind method and more complicated method where HK2 interfaces are required were omitted.
 *
 * @author Petr Bouda
 */
public abstract class AbstractBinder implements Binder {

    private List<Binding> internalBindings = new ArrayList<>();

    private List<AbstractBinder> installed = new ArrayList<>();

    private InjectionManager injectionManager;

    private boolean configured = false;

    /**
     * Implement to provide binding definitions using the exposed binding methods.
     */
    protected abstract void configure();

    /**
     * Sets {@link InjectionManager} to be able to create instance providers using the injection manager. {@code InjectionManager}
     * should be called before the invocation of {@link #configure()}, otherwise immediate invocation {@link Provider#get()}
     * returns
     *
     * @param injectionManager injection manager to create a provider.
     */
    void setInjectionManager(InjectionManager injectionManager) {
        this.injectionManager = injectionManager;
    }

    /**
     * Creates a new instance of {@link Provider} which is able to retrieve a managed instance registered in
     * {@link InjectionManager}. If {@code InjectionManager} is {@code null} at the time of calling {@link Provider#get()} then
     * {@link IllegalStateException} is thrown.
     *
     * @param clazz class of managed instance.
     * @param <T>   type of the managed instance returned using provider.
     * @return provider with instance of managed instance.
     */
    protected final <T> Provider<T> createManagedInstanceProvider(Class<T> clazz) {
        return () -> {
            if (injectionManager == null) {
                throw new IllegalStateException(LocalizationMessages.INJECTION_MANAGER_NOT_PROVIDED());
            }
            return injectionManager.getInstance(clazz);
        };
    }

    /**
     * Start building a new class-based service binding.
     * <p>
     * Does NOT bind the service type itself as a contract type.
     *
     * @param <T>         service type.
     * @param serviceType service class.
     * @return initialized binding builder.
     */
    public <T> ClassBinding<T> bind(Class<T> serviceType) {
        ClassBinding<T> binding = Bindings.service(serviceType);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Binds the provided binding and return the same instance.
     *
     * @param binding binding.
     * @return the same provided binding.
     */
    public Binding bind(Binding binding) {
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new class-based service binding.
     * <p>
     * Binds the service type itself as a contract type.
     *
     * @param <T>         service type.
     * @param serviceType service class.
     * @return initialized binding builder.
     */
    public <T> ClassBinding<T> bindAsContract(Class<T> serviceType) {
        ClassBinding<T> binding = Bindings.serviceAsContract(serviceType);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new generic type-based service binding.
     * <p>
     * Binds the generic service type itself as a contract type.
     *
     * @param <T>         service type.
     * @param serviceType generic service type information.
     * @return initialized binding builder.
     */
    public <T> ClassBinding<T> bindAsContract(GenericType<T> serviceType) {
        ClassBinding<T> binding = Bindings.service(serviceType);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new generic type-based service binding.
     * <p>
     * Binds the generic service type itself as a contract type.
     *
     * @param serviceType generic service type information.
     * @return initialized binding builder.
     */
    public ClassBinding<Object> bindAsContract(Type serviceType) {
        ClassBinding<Object> binding = Bindings.serviceAsContract(serviceType);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new instance-based service binding. The binding is naturally
     * considered to be a {@link javax.inject.Singleton singleton-scoped}.
     * <p>
     * Does NOT bind the service type itself as a contract type.
     *
     * @param <T>     service type.
     * @param service service instance.
     * @return initialized binding builder.
     */
    public <T> InstanceBinding<T> bind(T service) {
        InstanceBinding<T> binding = Bindings.service(service);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new supplier class-based service binding.
     *
     * @param <T>           service type.
     * @param supplierType  service supplier class.
     * @param supplierScope factory scope.
     * @return initialized binding builder.
     */
    public <T> SupplierClassBinding<T> bindFactory(
            Class<? extends Supplier<T>> supplierType, Class<? extends Annotation> supplierScope) {
        SupplierClassBinding<T> binding = Bindings.supplier(supplierType, supplierScope);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new supplier class-based service binding.
     * <p>
     * The supplier itself is bound in a per-lookup scope.
     *
     * @param <T>          service type.
     * @param supplierType service supplier class.
     * @return initialized binding builder.
     */
    public <T> SupplierClassBinding<T> bindFactory(Class<? extends Supplier<T>> supplierType) {
        SupplierClassBinding<T> binding = Bindings.supplier(supplierType);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new supplier instance-based service binding.
     *
     * @param <T>     service type.
     * @param factory service instance.
     * @return initialized binding builder.
     */
    public <T> SupplierInstanceBinding<T> bindFactory(Supplier<T> factory) {
        SupplierInstanceBinding<T> binding = Bindings.supplier(factory);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Start building a new injection resolver binding. The injection resolver is naturally
     * considered to be a {@link javax.inject.Singleton singleton-scoped}.
     * <p>
     * There is no need to provide any additional information. Other method on {@link Binding}
     * will be ignored.
     *
     * @param <T>      type of the injection resolver.
     * @param resolver injection resolver instance.
     * @return initialized binding builder.
     */
    public <T extends InjectionResolver> InjectionResolverBinding<T> bind(T resolver) {
        InjectionResolverBinding<T> binding = Bindings.injectionResolver(resolver);
        internalBindings.add(binding);
        return binding;
    }

    /**
     * Adds all binding definitions from the binders to the binding configuration.
     *
     * @param binders binders whose binding definitions should be configured.
     */
    public final void install(AbstractBinder... binders) {
        Arrays.stream(binders)
                .filter(Objects::nonNull)
                .forEach(installed::add);
    }

    @Override
    public Collection<Binding> getBindings() {
        invokeConfigure();
        List<Binding> bindings = installed.stream()
                .flatMap(binder -> Bindings.getBindings(injectionManager, binder).stream())
                .collect(Collectors.toList());
        bindings.addAll(internalBindings);
        return bindings;
    }

    private void invokeConfigure() {
        if (!configured) {
            configure();
            configured = true;
        }
    }
}