zipkin2.Component Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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
*
* http://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 zipkin2;
import java.io.Closeable;
import java.io.IOException;
/**
* Components are object graphs used to compose a zipkin service or client. For example, a storage
* component might return a query api.
*
* Components are lazy with regards to I/O. They can be injected directly to other components so
* as to avoid crashing the application graph if a network service is unavailable.
*/
public abstract class Component implements Closeable {
/**
* Answers the question: Are operations on this component likely to succeed?
*
*
Implementations should initialize the component if necessary. It should test a remote
* connection, or consult a trusted source to derive the result. They should use least resources
* possible to establish a meaningful result, and be safe to call many times, even concurrently.
*
* @see CheckResult#OK
*/
public CheckResult check() {
return CheckResult.OK;
}
/**
* Closes any network resources created implicitly by the component.
*
*
For example, if this created a connection, it would close it. If it was provided one, this
* would close any sessions, but leave the connection open.
*/
@Override public void close() throws IOException {
}
}