AuthenticationManagerSupplier

AuthenticationManagerSupplier.java

/*
 * Copyright 2020-2021 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.
 */

import org.springframework.boot.context.event.ApplicationStartedEvent;
import org.springframework.context.event.EventListener;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.stereotype.Component;

import java.util.function.Supplier;

/**
 * @author Steve Riesenberg
 */
@Component
public class AuthenticationManagerSupplier implements Supplier<AuthenticationManager> {
    private final AuthenticationManagerBuilder authenticationManagerBuilder;
    private AuthenticationManager authenticationManager;

    public AuthenticationManagerSupplier(AuthenticationManagerBuilder authenticationManagerBuilder) {
        this.authenticationManagerBuilder = authenticationManagerBuilder;
    }

    @EventListener
    public void onApplicationStarted(ApplicationStartedEvent event) {
        this.authenticationManager = this.authenticationManagerBuilder.getObject();
    }

    @Override
    public AuthenticationManager get() {
        if (this.authenticationManager == null) {
            throw new IllegalStateException(
                    "Application has not yet started. Please wait for application to start before accessing the AuthenticationManager.");
        }

        return this.authenticationManager;
    }
}