/*
* Copyright 2012-2019 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.cloud;
import org.springframework.core.env.Environment;
/**
* Simple detection for well known cloud platforms. For more advanced cloud provider
* integration consider the Spring Cloud project.
*
* @author Phillip Webb
* @since 1.3.0
* @see "https://cloud.spring.io"
*/
public enum CloudPlatform {
/**
* Cloud Foundry platform.
*/
CLOUD_FOUNDRY {
@Override
public boolean isActive(Environment environment) {
return environment.containsProperty("VCAP_APPLICATION") || environment.containsProperty("VCAP_SERVICES");
}
},
/**
* Heroku platform.
*/
HEROKU {
@Override
public boolean isActive(Environment environment) {
return environment.containsProperty("DYNO");
}
};
/**
* Determines if the platform is active (i.e. the application is running in it).
* @param environment the environment
* @return if the platform is active.
*/
public abstract boolean isActive(Environment environment);
/**
* Returns if the platform is behind a load balancer and uses
* {@literal X-Forwarded-For} headers.
* @return if {@literal X-Forwarded-For} headers are used
*/
public boolean isUsingForwardHeaders() {
return true;
}
/**
* Returns the active {@link CloudPlatform} or {@code null} if one cannot be deduced.
* @param environment the environment
* @return the {@link CloudPlatform} or {@code null}
*/
public static CloudPlatform getActive(Environment environment) {
if (environment != null) {
for (CloudPlatform cloudPlatform : values()) {
if (cloudPlatform.isActive(environment)) {
return cloudPlatform;
}
}
}
return null;
}
}
枚举型中的实例隐式地用static final修饰过。
枚举型作为某个类中的成员字段也隐式地用static final修饰过。
