org.springframework.boot.BootstrapContext Maven / Gradle / Ivy
/*
* Copyright 2012-2020 the original author or authors.
*
* 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
*
* https://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 org.springframework.boot;
import java.util.function.Supplier;
import org.springframework.context.ApplicationContext;
import org.springframework.core.env.Environment;
/**
* A simple bootstrap context that is available during startup and {@link Environment}
* post-processing up to the point that the {@link ApplicationContext} is prepared.
*
* Provides lazy access to singletons that may be expensive to create, or need to be
* shared before the {@link ApplicationContext} is available.
*
* @author Phillip Webb
* @since 2.4.0
*/
public interface BootstrapContext {
/**
* Return an instance from the context if the type has been registered. The instance
* will be created it if it hasn't been accessed previously.
* @param the instance type
* @param type the instance type
* @return the instance managed by the context
* @throws IllegalStateException if the type has not been registered
*/
T get(Class type) throws IllegalStateException;
/**
* Return an instance from the context if the type has been registered. The instance
* will be created it if it hasn't been accessed previously.
* @param the instance type
* @param type the instance type
* @param other the instance to use if the type has not been registered
* @return the instance
*/
T getOrElse(Class type, T other);
/**
* Return an instance from the context if the type has been registered. The instance
* will be created it if it hasn't been accessed previously.
* @param the instance type
* @param type the instance type
* @param other a supplier for the instance to use if the type has not been registered
* @return the instance
*/
T getOrElseSupply(Class type, Supplier other);
/**
* Return an instance from the context if the type has been registered. The instance
* will be created it if it hasn't been accessed previously.
* @param the instance type
* @param the exception to throw if the type is not registered
* @param type the instance type
* @param exceptionSupplier the supplier which will return the exception to be thrown
* @return the instance managed by the context
* @throws X if the type has not been registered
* @throws IllegalStateException if the type has not been registered
*/
T getOrElseThrow(Class type, Supplier exceptionSupplier) throws X;
/**
* Return if a registration exists for the given type.
* @param the instance type
* @param type the instance type
* @return {@code true} if the type has already been registered
*/
boolean isRegistered(Class type);
}